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Table of Content
28 April 2022, Volume 44 Issue 4
    Photoacoustic detection of follicular thyroid carcinoma using targeted Nano-Au-Tripods
    Yang Gui, Kai Cheng, Ruojiao Wang, Sirui Liu, Chenyang Zhao, Rui Zhang, Ming Wang, Zhen Cheng, Meng Yang
    2022, 44(4):  1-7.  doi:10.1016/j.cjche.2021.06.013
    Abstract ( 39 )   PDF (4012KB) ( 47 )  
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    Follicular thyroid carcinoma (FTC) is the second most common form of thyroid malignancy, and it is associated with more aggressive growth and worse long-term survival outcomes relative to papillary thyroid carcinoma (PTC). Reliable approaches to preoperative FTC detection, however, remain to be established. Herein, a targeted Affibody-Au-Tripod nanoprobe was developed and successfully utilized to facilitate the targeted photoacoustic imaging (PAI) of epidermal growth factor receptor (EGFR)-positive cells and tumors. These Affibody-Au-Tripods were found to be highly sensitive and specific for cells expressing EGFR when used as a PA contrast agent in vitro, and studies conducted in an FTC-133 subcutaneous tumor model system in mice further revealed that these Affibody-Au-Tripods were able to specifically target these EGFR-expressing tumors while providing a strong photoacoustic signal in vivo. Importantly, these nanoprobes exhibited negligible cytotoxicity and robust chemical and physical stability, making Affibody-Au-Tripods promising candidates for targeted PAI-based FTC diagnosis. In addition, these nanoprobes have the potential to facilitate the individualized treatment of patients harboring EGFR-positive tumors.
    Effect of inlet area on the performance of a two-stage cyclone separator
    Jihe Chen, Zhongan Jiang, Bin Yang, Yapeng Wang, Fabin Zeng
    2022, 44(4):  8-19.  doi:10.1016/j.cjche.2021.06.003
    Abstract ( 42 )   PDF (7798KB) ( 29 )  
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    The cyclone separator is an important separation device. This paper presents a new type of embedded two-stage cyclone, which includes a 2nd-stage cyclone (internal traditional cyclone) with multiple inlets and a 1st-stage cyclone (outer cylinder) that unifies the 2nd-stage cyclone inlets into one inlet. The Taguchi experimental method was used to study the two-stage cyclone separator's inlet area on its performance. Studies have shown that the increase of the 1st-stage cyclone inlet area and the increase in the number of 2nd-stage cyclone inlets (N) positively affect reducing the pressure drop and a negative effect on efficiency. It is recommended to use 2S (the original 1st-stage cyclone inlet area) of the 1st-stage cyclone inlet area and 2N of the 2nd-stage cyclone inlets when separating fine particles. Compared with a traditional cyclone, the pressure drop is reduced by 1303 Pa, the mass separation efficiency (Eq) is increased by 0.56%, and the number separation efficiency (En) is increased by 2.05%. When separating larger particles, it is recommended to use 2S of the 1st-stage cyclone inlet area and 4N of the 2nd-stage cyclone inlets. Compared with a traditional cyclone, although En decreases slightly, the pressure drop is reduced by 3055 Pa, and the Eq is increased by 0.56%. The research results provide new insight into the design of the cyclone.
    Recovery of lithium using H4Mn3.5Ti1.5O12/reduced graphene oxide/polyacrylamide composite hydrogel from brine by Ads-ESIX process
    Jingsi Cui, Huanxi Xu, Yanfeng Ding, Jingjing Tian, Xu Zhang, Guanping Jin
    2022, 44(4):  20-28.  doi:10.1016/j.cjche.2021.05.009
    Abstract ( 27 )   PDF (5039KB) ( 59 )  
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    Powdery Li+-imprinted manganese oxides adsorbent was widely used to the recovery of Li+, but there are some difficulties, such as poor stability in acid solution, inconvenience of operation and separation. In this work, a useful hydrogel composite based H4Mn3.5Ti1.5O12/reduced graphene oxide/polyacrylamide (HMTO-rGO/PAM) was fabricated by thermal initiation method with promising stable, conductive and selective properties. The resulting materials were characterized by field emission scanning electron microscope, infrared absorption spectrum, X-ray diffraction, X-ray photoelectron spectroscopy and electrochemical techniques. The recovery of Li+ was investigated using HMTO-rGO/PAM from brine by a separated two-stage sorption statically and electrically switched ion exchange desorption process. The adsorption capacity of 51.5 mg·g-1 could be achieved with an initial Li+ concentration of 200 mg·L-1 in pH 10, at 45 ℃ for 12 h. Li+ ions could be quickly desorbed by cyclic voltammetry (CV) in pH 3, 0.1 mol·L-1 HCl/NH4Cl accompanying the exchange of Li+ and H+(NH4+) and the transfer of LMTO-rGO/PAM to HMTO-rGO/PAM.
    Three-scale integrated optimization model of furnace simulation, cyclic scheduling, and supply chain of ethylene plants
    Kexin Bi, Mingyu Yan, Shuyuan Zhang, Tong Qiu
    2022, 44(4):  29-40.  doi:10.1016/j.cjche.2021.03.038
    Abstract ( 26 )   PDF (6871KB) ( 116 )  
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    In order to explore the potential of profit margin improvement, a novel three-scale integrated optimization model of furnace simulation, cyclic scheduling, and supply chain of ethylene plants is proposed and evaluated. A decoupling strategy is proposed for the solution of the three-scale model, which uses our previously proposed reactor scale model for operation optimization and then transfers the obtained results as a parameter table in the joint MILP optimization of plant-supply chain scale for cyclic scheduling. This optimization framework simplifies the fundamental mixed-integer nonlinear programming (MINLP) into several sub-models, and improves the interpretability and extendibility. In the evaluation of an industrial case, a profit increase at a percentage of 3.25% is attained in optimization compared to the practical operations. Further sensitivity analysis is carried out for strategy evolving study when price policy, supply chain, and production requirement parameters are varied. These results could provide useful suggestions for petrochemical enterprises on thermal cracking production.
    Insights into biobased epoxidized fatty acid isobutyl esters from biodiesel: Preparation and application as plasticizer
    Xiaojiang Liang, Fengjiao Wu, Qinglong Xie, Zhenyu Wu, Jinjin Cai, Congwen Zheng, Junhong Fu, Yong Nie
    2022, 44(4):  41-50.  doi:10.1016/j.cjche.2021.03.048
    Abstract ( 31 )   PDF (6673KB) ( 114 )  
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    Biodiesel was used to prepare epoxidized fatty acid isobutyl esters (Ep-FABEs) as a biobased plasticizer in this work. Transesterification of biodiesel with isobutanol catalyzed by tetrabutyl titanate was carried out in a gas-liquid tower reactor. The conversion achieved nearly 100% within 5 h under the reaction temperature, the mass ratio of catalyst to fatty acid methyl esters (FAMEs), and isobutanol to FAMEs total molar ratio of 180 ℃, 0.4 %(mass), and 5.4:1, respectively. In addition, kinetic model of the transesterification reaction was developed at 150–190 ℃. The calculated activation energy was 48.93 kJ·mol-1. Then, the epoxidation of obtained fatty acid isobutyl esters (FABEs) was conducted in the presence of formic acid and hydrogen peroxide. The Ep-FABEs was further analyzed for its plasticizing effectiveness to replace dioctyl phthalate (DOP) and compared with conventional epoxy plasticizer epoxidized fatty acid methyl esters (Ep-FAMEs). The results indicated that the thermal stability and mechanical properties of PVC films with Ep-FABEs plasticizer were significantly improved compared with those plasticized with DOP. In addition, the extraction resistance and migration stability of Ep-FABEs were better than those of Ep-FAMEs. Overall, the prepared Ep-FABEs via structural modification of biodiesel proved to be a promising biobased plasticizer.
    Influences of fluid physical properties, solid particles, and operating conditions on the hydrodynamics in slurry reactors
    He Yang, Aqiang Chen, Shujun Geng, Jingcai Cheng, Fei Gao, Qingshan Huang, Chao Yang
    2022, 44(4):  51-71.  doi:10.1016/j.cjche.2021.03.045
    Abstract ( 67 )   PDF (7546KB) ( 42 )  
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    Slurry reactors are popular in many industrial processes, involved with numerous chemical and biological mixtures, solid particles with different concentrations and properties, and a wide range of operating conditions. These factors can significantly affect the hydrodynamic in the slurry reactors, having remarkable effects on the design, scale-up, and operation of the slurry reactors. This article reviews the influences of fluid physical properties, solid particles, and operating conditions on the hydrodynamics in slurry reactors. Firstly, the influence of fluid properties, including the density and viscosity of the individual liquid and gas phases and the interfacial tension, has been reviewed. Secondly, the solid particle properties (i.e., concentration, density, size, wettability, and shape) on the hydrodynamics have been discussed in detail, and some vital but often ignored features, especially the influences of particle wettability and shape, as well as the variation of surface tension because of solid concentration alteration, are highlighted in this work. Thirdly, the variations of physical properties of fluids, hydrodynamics, and bubble behavior resulted from the temperature and pressure variations are also summarized, and the indirect influences of pressure on viscosity and surface tension are addressed systematically. Finally, conclusions and perspectives of these notable influences on the design and scale-up of industrial slurry reactors are presented.
    Numerical simulation of local and global mixing/segregation characteristics in a gas–solid fluidized bed
    Zhen Wan, Youjun Lu
    2022, 44(4):  72-86.  doi:10.1016/j.cjche.2021.03.034
    Abstract ( 41 )   PDF (10197KB) ( 30 )  
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    Researches on solids mixing and segregation are of great significance for the operation and design of fluidized bed reactors. In this paper, the local and global mixing and segregation characteristics of binary mixtures were investigated in a gas–solid fluidized bed by computational fluid dynamics-discrete element method (CFD-DEM) coupled approach. A methodology based on solids mixing entropy was developed to quantitatively calculate the mixing degree and time of the bed. The mixing curves of global mixing entropy were acquired, and the distribution maps of local mixing entropy and mixing time were also obtained. By comparing different operating conditions, the effects of superficial gas velocity, particle density ratio and size ratio on mixing/segregation behavior were discussed. Results showed that for the partial mixing state, the fluidized bed can be divided into three parts along the bed height: complete segregation area, transition area and stable mixing area. These areas showed different mixing/segregation processes. Increasing gas velocity promoted the local and global mixing of binary mixtures. The increase in particle density ratio and size ratio enlarged the complete segregation area, reduced the mixing degree and increased the mixing time in the stable mixing area.
    Nb2O5 promoted Pd/AC catalyst for selective phenol hydrogenation to cyclohexanone
    Chunhua Zhang, Zhengyan Qu, Hong Jiang, Rizhi Chen, Weihong Xing
    2022, 44(4):  87-93.  doi:10.1016/j.cjche.2021.04.038
    Abstract ( 54 )   PDF (2723KB) ( 33 )  
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    Phenol hydrogenation is a green route to prepare cyclohexanone, an intermediate for the production of nylon 66 and nylon 6. The development of high-performance catalysts still keeps a great challenge. Herein, the activated carbon (AC) was modified with an acidic material Nb2O5 to adjust the microstructure and surface properties of AC, and the influences of the calcination temperature and Nb2O5 content on the catalytic performance of the Pd/AC-Nb2O5 catalysts for the phenol hydrogenation to cyclohexanone were investigated. The Nb2O5 with proper content can be highly uniformly distributed on the AC surface, enhancing the acidity of the Pd/AC-Nb2O5 catalysts with comparable specific surface area and Pd dispersion, thereby improving the catalytic activity. The hybrid Pd/AC-10Nb2O5-500 catalyst exhibits the synergistic effect between the Pd nanoparticles and AC-10Nb2O5, which enhances the catalytic activity for the hydrogenation of phenol. Furthermore, the as-prepared Pd/AC-10Nb2O5-500 catalyst shows good reusability during 7 reaction cycles.
    Inhibition of hematite on acid mine drainage caused by chalcopyrite biodissolution
    Baojun Yang, Wen Luo, Maoxin Hong, Jun Wang, Xueduan Liu, Min Gan, Guanzhou Qiu
    2022, 44(4):  94-104.  doi:10.1016/j.cjche.2022.01.001
    Abstract ( 53 )   PDF (8317KB) ( 20 )  
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    Even though biodissolution of chalcopyrite is considered to be one of the key contributors in the formation of acid mine drainage (AMD), there are few studies to control AMD by inhibiting chalcopyrite biodissolution. Therefore, a novel method of using hematite to inhibit chalcopyrite biodissolution was proposed and verified. The results indicated that chalcopyrite biodissolution could be significantly inhibited by hematite, which consequently decreased the formation of AMD. In the presence of hematite, the final biodissolution rate of chalcopyrite decreased from 57.9% to 44.4% at 20 day. This in turn suggested that the formation of AMD was effectively suppressed under such condition. According to the biodissolution results, mineral composition and morphology analyses, and electrochemical analysis, it was shown that hematite promoted the formation and accumulation of passivation substances (jarosite and Cu2-xS) on chalcopyrite surface, thus inhibiting the biodissolution of chalcopyrite and limiting the formation of AMD.
    The high catalytic activity and strong stability of 3%Fe/AC catalysts for catalytic wet peroxide oxidation of m-cresol: The role of surface functional groups and FeOx particles
    Peiwei Han, Chunhua Xu, Yamin Wang, Chenglin Sun, Huangzhao Wei, Haibo Jin, Ying Zhao, Lei Ma
    2022, 44(4):  105-114.  doi:10.1016/j.cjche.2021.04.040
    Abstract ( 36 )   PDF (9991KB) ( 30 )  
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    FeO supported on activated carbon (AC) has been shown to be an ideal catalyst for catalytic wet peroxide oxidation (CWPO) due to its high CWPO reaction activity and stability. Although there have been some studies on the mechanism of Fe/AC catalysis in CWPO, the specific contribution of each component (surface oxygen groups and FeOx on AC) inside an Fe/AC catalyst and their corresponding reaction mechanism remain unclear, and the reaction stability of CWPO catalysts has rarely been discussed. Then the optimal CWPO catalyst in our laboratory, 3%Fe/AC, was selected. (1) By removing certain components on the AC through heat treatment, its contribution to the reaction and the corresponding reaction mechanism were investigated. With the aid of temperature-programmed desorption–mass spectrometry (TPD–MS) and the CWPO reaction, the normalized catalytic contributions of components were shown to be: 37.3% (carboxylic groups), 5.3% (anhydride), 19.3% (ether/hydroxyl), -71.4% (carbonyl groups) and 100% (FeOx), respectively. DFT calculation and EPR analysis confirmed that carboxylic groups and Fe2O3 are able to activate the H2O2 to generate ·OH. (2) The catalysts at were characterized at different reaction times (0 h, 450 h, 900 h, 1350 h, and 1800 h) by TPD–MS and Mössbauer spectroscopy. Results suggested that the number of carboxylic goups gradually increased and the size of paramagnetic Fe2O3 particle crystallites gradually increased as the reactions progressed. The occurrence of strong interactions between metal oxides and AC was also confirmed. Due to these effects, the strong stability of 3%Fe/AC was further improved. Therefore, the reasons for the high activity and strong stability of 3%Fe/AC in CWPO were clearly shown. We believe that this work provides an idea of the removal of cresols from wastewater into the introduction to show the potential applications of CWPO.
    Performance of a synthetic resin for lithium adsorption in waste liquid of extracting aluminum from fly-ash
    Zhengguo Xu, Xiaochong Wang, Shuying Sun
    2022, 44(4):  115-123.  doi:10.1016/j.cjche.2021.03.036
    Abstract ( 35 )   PDF (5912KB) ( 63 )  
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    In this study, we investigated the performance of a synthetic resin for the adsorption of Li from pre-desilicated solution which is the waste liquid produced by extracting aluminum from fly ash. The adsorption kinetics and isotherms of the resin were obtained and analyzed. The saturated adsorption sites of the resin were in agreement with the quasi-second-order kinetic model. Then, the pore diffusion model (PDM) was applied to represent the lithium adsorption kinetics which confirming that the external mass is the limiting step. Moreover, we evaluated the adsorption properties of this resin in fixed-bed mode. We established a feasible extraction process for Li from strong alkaline solutions with low Li concentrations. The process parameters, such as the flow rate, initial adsorption solution concentration, water washing process, desorption agent concentration, and flow rate were studied. The desorption rate of the Li+ ions was directly proportional with the concentration of the desorption agent. The time required to accumulate Li decreased as the hydrochloric acid concentration and flow rate increased. Time of the peak appeared increased from 0.5 bed volume (BV) to 2.5 BV as the concentration was increased from 1 to 3 mol·L-1, and the peak increased from 231 to 394 mg·L-1. The resin presented good selectivity for Li+ ions and could effectively separate impurity ions from the pre-desilication solution.
    Experimental and theoretical study on N-hydroxyphthalimide and its derivatives catalyzed aerobic oxidation of cyclohexylbenzene
    Yufei Yang, Jieyi Ma, Junyan Wu, Weixia Zhu, Yadong Zhang
    2022, 44(4):  124-130.  doi:10.1016/j.cjche.2021.06.017
    Abstract ( 55 )   PDF (1613KB) ( 62 )  
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    The liquid phase oxidation of cyclohexylbenzene (CHB) is a new green synthetic approach to cyclohexylbenzene-1-hydroperoxide (CHBHP), a key intermediate for preparing phenol and cyclohexanone. In this work, aryl-substituted (Cl and Br) derivatives of N-hydroxyphthalimide (NHPI) were synthesized and their catalytic performances for CHB oxidation were studied. In addition, geometric optimization and transition state search were performed using DFT calculations. Both experimental and theoretical studies have proven that chloro-substitution on NHPI can significantly improve its catalytic effects on the oxidation of CHB by oxygen. Compared with NHPI, CHB conversion and selectivity of CHBHP over Cl4NHPI were increased by 10.47% and 13.24%. The strategy of aryl -substituting NHPI with halogen atoms proposed in this study would provide a potential way to the development of new NHPI-based catalysts for aerobic oxidation reactions.
    Measuring absolute adsorption in porous rocks using oscillatory motions of a spring-mass system
    Younki Cho, Ryan Lo, Keerthana Krishnan, Xiaolong Yin, Hossein Kazemi
    2022, 44(4):  131-139.  doi:10.1016/j.cjche.2022.01.002
    Abstract ( 39 )   PDF (2285KB) ( 46 )  
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    We present an oscillation-based method to measure absolute adsorption, or total gas, contained in porous rocks without and with excess adsorption. Experiments conducted with a macroporous Berea sandstone sample in nitrogen where excess adsorption is negligible show that absolute adsorption can be obtained after the added mass of co-accelerated gas outside the sample is subtracted. In experiments conducted in propane with a crushed Niobrara shale sample with micro- and mesopores, absolute adsorption included significant excess adsorption. After subtracting both the added mass outside the sample and the gas that would be in the sample assuming no excess adsorption existed, estimated excess adsorption of propane is in good agreement with that projected based on capillary condensation of propane in the volume of mesopores.
    Enhanced electrochemical performance of garnet-based solid-state lithium metal battery with modified anodic and cathodic interfaces
    Deen Yan, Huangwang Mai, Wen Chen, Wei Yang, Hanbo Zou, Shengzhou Chen
    2022, 44(4):  140-147.  doi:10.1016/j.cjche.2021.03.030
    Abstract ( 46 )   PDF (8583KB) ( 49 )  
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    Due to high ionic conductivity and wide electrochemical window, the garnet solid electrolyte is considered as the most promising candidate electrolyte for solid-state lithium metal batteries. However, the high contact impedance between metallic lithium and the garnet solid electrolyte surface seriously hampers its further application. In this work, a Li-(ZnO)x anode is prepared by the reaction of zinc oxide with metallic lithium and in situ coated on the surface of Li6.8La3Zr1.8Ta0.2O12(LLZTO). The anode can be perfectly bound to the surface of LLZTO solid electrolyte, and the anode/electrolyte interfacial resistance was reduced from 2319 to 33.75 Ω·cm2. The Li-(ZnO)0.15|LLZTO|Li-(ZnO)0.15 symmetric battery exhibits a stable Li striping/plating process during charge-discharging at a constant current density of 0.1 mA·cm-2 for 100 h at room temperature. Moreover, a Li-(ZnO)0.15|LLZTO-SPE|LFP full battery, comprised of a polyethylene oxide-based solid polymer electrolyte (SPE) film as an interlayer between LiFePO4 (LFP) cathode and LLZTO solid electrolyte, presents an excellent performance at 60 ℃. The discharge capacity of the full battery reaches 140 mA·h·g-1 at 0.1 C and the capacity attenuation is less than 3% after 50 cycles.
    Insights into high-efficient removal of tetracycline by a codoped mesoporous carbon adsorbent
    Xinyu Chen, Shuo Shi, Ximei Han, Min Li, Ying Nian, Jing Sun, Wentao Zhang, Tianli Yue, Jianlong Wang
    2022, 44(4):  148-156.  doi:10.1016/j.cjche.2021.07.023
    Abstract ( 36 )   PDF (6385KB) ( 46 )  
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    Adsorbents with simple preparation and high surface area have become increasingly prevalent for the removal of organic contaminants. Herein, a carbon nanoplate codoped by Co and N elements with abundant ordered mesoporous (Co/N-MCs) was applied as an adsorbent for tetracycline removal. Taking integrated advantages of ordered mesopores on carbon-based structures and N-doping inducing the strengthened π–π dispersion and generation of pyridinic N, as well as cobaltic nanoparticles embedded in carbon nanoplates, the Co/N-MCs was tailored for high efficiently absorbing tetracycline via π-π interaction, Lewis acid-base interaction, metal complexation and electrostatic attraction. The Co/N-MCs had the advantages of high surface area, porous structure, plenty adsorption sites, and easy separation. As such, the as-prepared Co/N-MCs adsorbents significantly enhanced tetracycline removal performance with a maximum adsorption capacity of 344.83 mg·g-1 at pH 6 and good reusability, which was finally applied to removal tetracycline from tap water sample. Furthermore, the adsorption process towards tetracycline hydrochloride could be well attributed to the pseudo-second-order kinetic and Langmuir isotherm models. Compared with traditional carbon-based adsorbents, it owns a simpler synthesis method and a higher adsorption capacity, as well as it is a promising candidate for water purification.
    Ternary Ni2P/Bi2MoO6/g-C3N4 composite with Z-scheme electron transfer path for enhanced removal broad-spectrum antibiotics by the synergistic effect of adsorption and photocatalysis
    Feng Guo, Zhihao Chen, Xiliu Huang, Longwen Cao, Xiaofang Cheng, Weilong Shi, Lizhuang Chen
    2022, 44(4):  157-168.  doi:10.1016/j.cjche.2021.08.024
    Abstract ( 65 )   PDF (10719KB) ( 29 )  
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    Constructing the stable, low-cost, efficient, and highly adaptable visible light-driven photocatalyst to implement the synergistic effect of photocatalysis and adsorption has been excavated a promising strategy to deal with antibiotic pollution in water bodies. Herein, a novel 3D ternary Z-scheme heterojunction photocatalyst Ni2P/Bi2MoO6/g-C3N4 (Ni2P/BMO/CN) was fabricated by a simple solvothermal method in which the broad spectrum antibiotics (mainly tetracyclines and supplemented by quinolones) were used as target pollution sources to evaluate its adsorption and photocatalytic performance. Notably, the Z-scheme composite significantly exhibit the enhancement for degradation efficiency of tetracycline and other antibiotic by using Ni2P nanoparticles as electron conductor. Active species capture experiment and electron spin resonance (ESR) technology reveal the mechanism of Z-scheme Ni2P/BMO/CN photocatalytic reaction in detail. In addition, based on the identification of intermediates by liquid chromatography–mass spectroscopy (LC–MS), the possible photocatalytic degradation pathways of TC were proposed.
    Facile synthesis of metal-organic frameworks embedded in interconnected macroporous polymer as a dual acid-base bifunctional catalyst for efficient conversion of cellulose to 5-hydroxymethylfurfural
    Yanan Wei, Yunlei Zhang, Bing Li, Wen Guan, Changhao Yan, Xin Li, Yongsheng Yan
    2022, 44(4):  169-181.  doi:10.1016/j.cjche.2021.06.019
    Abstract ( 39 )   PDF (9242KB) ( 29 )  
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    5-Hydroxymethylfurfural (5-HMF), as a key platform compound for the conversion of biomass to various biomass-derived chemicals and biofuels, has been attracted extensive attention. In this research, using Pickering high internal phase emulsions (Pickering HIPEs) as template and functional metal-organic frameworks (MOFs, UiO-66-SO3H and UiO-66-NH2)/Tween 85 as co-stabilizers to synthesis the dual acid-base bifunctional macroporous polymer catalyst by one-pot process, which has excellent catalytic activity in the cascade reaction of converting cellulose to 5-HMF. The effects of the emulsion parameters including the amount of surfactant (ranging from 0.5% to 2.0% (mass)), the internal phase volume fraction (ranging from 75% to 90%) and the acid/base Pickering particles mass ratio (ranging from 0:6 to 6:0) on the morphology and catalytic performance of solid catalyst were systematically researched. The results of catalytic experiments suggested that the connected large pore size of catalyst can effectively improve the cellulose conversion, and the synergistic effect of acid and base active sites can effectively improve the 5-HMF yield. The highest 5-HMF yield, about 40.5%, can be obtained by using polymer/MOFs composite as catalyst (Poly-P12, the pore size of (53.3 ±11.3) μm, the acid density of 1.99 mmol·g-1 and the base density of 1.13 mol·g-1) under the optimal reaction conditions (130 ℃, 3 h). Herein, the polymer/MOFs composite with open-cell structure was prepared by the Pickering HIPEs templating method, which provided a favorable experimental basis and theoretical reference for achieving efficient production of high added-value product from abundant biomass.
    Component analysis and risk assessment of biogas slurry from biogas plants
    Lanting Ke, Xiaobin Liu, Bingqing Du, Yuanpeng Wang, Yanmei Zheng, Qingbiao Li
    2022, 44(4):  182-191.  doi:10.1016/j.cjche.2021.05.039
    Abstract ( 38 )   PDF (2254KB) ( 86 )  
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    Massive amounts of biogas slurry are produced due to the development of biogas plants. The pollution features and the risk of biogas slurry were fully evaluated in this work. Thirty-one biogas slurry samples were collected from sixteen different cities and five different raw materials biogas plants (e.g. cattle manure, swine manure, straw-manure mixture, kitchen waste and chicken manure). The chemical oxygen demand (COD), ammonia nitrogen (NH4+ - N), anions (e.g. Cl-,SO42-, NO3- and PO4-3), antibiotics (e.g. sulphonamides, quinolones, β2-receptor agonists, macrolides, tetracyclines and crystal violet) and heavy metals (e.g. Cu, Cd, As, Cr, Hg, Zn and Pb) contents from these biogas slurry samples were systematically investigated. On this basis, risk assessment of biogas slurry was also performed. The concentrations of COD, NH4+ and PO4-3 in biogas slurry samples with chicken manure as raw material were significantly higher than those of other raw materials. Therefore, the biogas slurry from chicken manure raw material demonstrated the most serious eutrophication threat. The antibiotic contents in biogas slurry samples from swine manure were the highest among five raw materials, mostly sulphonamides, quinolones and tetracyclines. Biogas slurry revealed particularly serious arsenic contamination and moderate potential ecological risk. The quadratic polynomial stepwise regression model can quantitatively describe the correlation among NH4+ - N, PO4-3 and heavy metals concentration of biogas slurry. This work demonstrated a universal potential threat from biogas slurry that can provide supporting data and theoretical basis for harmless treatment and reuse of biogas slurry.
    Dynamic optimization of 1,3-propanediol fermentation process: A switched dynamical system approach
    Xiang Wu, Yuzhou Hou, Kanjian Zhang, Ming Cheng
    2022, 44(4):  192-204.  doi:10.1016/j.cjche.2021.03.041
    Abstract ( 29 )   PDF (557KB) ( 45 )  
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    This paper considers a dynamic optimization problem (DOP) of 1,3-propanediol fermentation process (1,3-PFP). Our main contributions are as follows. Firstly, the DOP of 1,3-PFP is modeled as an optimal control problem of switched dynamical systems. Unlike the existing switched dynamical system optimal control problem, the state-dependent switching method is applied to design the switching rule. Then, in order to obtain the numerical solution, by introducing a discrete-valued function and using a relaxation technique, this problem is transformed into a nonlinear parameter optimization problem (NPOP). Although the gradient-based algorithm is very efficient for solving NPOPs, the existing algorithm is always trapped in a local minimum for such problems with multiple local minima. Next, in order to overcome this challenge, a gradient-based random search algorithm (GRSA) is proposed based on an improved gradient-based algorithm (IGA) and a novel random search algorithm (NRSA), which cannot usually be trapped in a local minimum. The convergence results are also established, and show that the GRSA is globally convergent. Finally, a DOP of 1,3-PFP is provided to illustrate the effectiveness of the GRSA proposed by this paper.
    Photocatalytic oxidative of Keggin-type polyoxometalate ionic liquid for enhanced extractive desulfurization in binary deep eutectic solvents
    Linlan Wu, Zhengxin Jiao, Suhang Xun, Minqiang He, Lei Fan, Chao Wang, Wenshu Yang, Wenshuai Zhu, Huaming Li
    2022, 44(4):  205-211.  doi:10.1016/j.cjche.2021.04.031
    Abstract ( 38 )   PDF (988KB) ( 31 )  
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    A series of novel binary deep eutectic solvents (DESs) composed of choline chloride (ChCl) and formic acid (HCOOH) with different molar ratios have been successfully synthesized and applied in extractive desulfurization (EDS). Keggin-type polyoxometallate ionic liquid [TTPh]3PW12O40 was prepared and used as catalyst to enhance the EDS capacity by means of photocatalytic oxidative process. Both of the DESs and [TTPh]3PW12O40 ionic liquid catalyst were characterized in detail by Fourier transform infrared spectroscopy spectra (FT-IR), elemental analysis, and X-ray photoelectron spectroscopy (XPS). It was found that the molar ratios of ChCl:HCOOH had a major impact on desulfurization performance, and the optimal desulfurization capacity 96.5% was obtained by ChCl/5HCOOH. Besides dibenzothiophene (DBT), the desulfurization efficiencies of 4-methylbenzothiophene (4-MDBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT), two kinds of DBT derivatives, were also investigated under the same experimental conditions. Moreover, the free radical scavenging experiments manifested that superoxide radical (·O2-) and hole (h+) played important roles in the desulfurization system. After further analysis of the oxidation products by gas chromatography-mass spectrometry (GC–MS), the possible reaction mechanism was proposed. Thus, photocatalytic oxidative has been proved to be one of the efficient approaches for enhancing the extractive desulfurization performance in DES.
    Study of intermolecular interactions in binary mixtures of methyl acrylate with benzene and methyl substituted benzenes at different temperatures: An experimental and theoretical approach
    Anil Kumar Nain
    2022, 44(4):  212-238.  doi:10.1016/j.cjche.2021.05.024
    Abstract ( 33 )   PDF (3804KB) ( 24 )  
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    The ultrasonic speeds, u and viscosities, η of the binary mixtures of methyl acrylate with benzene, toluene, o-xylene, m-xylene, p-xylene, and mesitylene over the whole mole fraction range were measured at six different temperatures and at atmospheric pressure. From the experimental data, the excess isentropic compressibility, KSE, excess ultrasonic speed, uE, excess molar isentropic compressibility, Ks,mE, excess specific impedance, ZEand deviations in viscosity, Δηhave been calculated. The partial molar isentropic compressions, Ks,m,1 and Ks,m,2, and excess partial molar isentropic compressions, ${\mathop K\limits^{ - E}}$s,m,1 and ${\mathop K\limits^{ - E}}$s,m,2 over the whole composition range, partial molar isentropic compressions, and , and excess partial molar isentropic compressions, $\mathop K\limits^{ - \hat E} $s,m,1 and $\mathop K\limits^{ - \hat E} $s,m,2 of the components at infinite dilution have also been calculated. The results specified the existence of weak interactions between unlike molecules, and these interactions follow the order: benzene > toluene > p-xylene > m-xylene > o-xylene > mesitylene. The magnitude of interactions was found to be dependent on the number and position of the methyl groups in these aromatic hydrocarbons.
    Enhanced straw fermentation process based on microbial electrolysis cell coupled anaerobic digestion
    Xinyu Yan, Bobo Wang, Hongxia Liang, Jie Yang, Jie Zhao, Fabrice Ndayisenga, Hongxun Zhang, Zhisheng Yu, Zhi Qian
    2022, 44(4):  239-245.  doi:10.1016/j.cjche.2021.05.020
    Abstract ( 33 )   PDF (3151KB) ( 37 )  
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    The low quality and yield of methane severely hinder the industrial application of straw biogas fermentation, and no effective solution has been found so far. In this study, a novel method was developed when a microbial electrolysis cell (MEC) was coupled with normal anaerobic fermentation to enhance methane yield and purity. The fermentation process achieved a methane purity of more than 85%, which is considerably higher than that of previously published reports. With microbial stimulation and an electric current, the degradation of fibers has been greatly enhanced. The MEC system substantially improved the yield and purity of biogas, bringing a new path to the synthesis of methane by carbon dioxide and hydrogen ions in solution under electron irradiation. Electrochemical index analysis showed extra methane synthesis, due to the external circuit electron transfer. The results of the gas chromatography and solid degradation rate showed that the carbon source of extra methane was CO2 produced during normal fermentation and additional volatile solid degradation. These results show that the MEC considerably enhanced the quality and yield of methane in the straw fermentation process, providing insights into normal anaerobic fermentation.
    Patterned catalyst layer boosts the performance of proton exchange membrane fuel cells by optimizing water management
    Yingjie Zhou, Wenhui Zhang, Shengwei Yu, Haibo Jiang, Chunzhong Li
    2022, 44(4):  246-252.  doi:10.1016/j.cjche.2021.06.001
    Abstract ( 33 )   PDF (10316KB) ( 25 )  
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    Mass transport is crucial to the performance of proton exchange membrane fuel cells, especially at high current densities. Generally, the oxygen and the generated water share same transmission medium but move towards opposite direction, which leads to serious mass transfer problems. Herein, a series of patterned catalyst layer were prepared with a simple one-step impressing method using nylon sieves as templates. With grooves 100 μm in width and 8 μm in depth on the surface of cathode catalyst layer,the maximum power density of fuel cell increases by 10% without any additional durability loss while maintaining a similar electrochemical surface area. The concentration contours calculated by finite element analysis reveal that the grooves built on the surface of catalyst layer serve to accumulate the water nearby while oxygen tends to transfer through relatively convex region, which results from capillary pressure difference caused by the pore structure difference between the two regions. The separation of oxidant gas and generated water avoids mass confliction thus boosts mass transport efficiency.
    Lead removal from aqueous medium using fruit peels and polyaniline composites in aqueous and non-aqueous solvents in the presence of polyethylene glycol
    Iman Farirzadeh, Majid Riahi Samani, Davood Toghraie
    2022, 44(4):  253-259.  doi:10.1016/j.cjche.2020.09.049
    Abstract ( 64 )   PDF (5774KB) ( 45 )  
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    In the present study, composites of Polyaniline and some fruit peels were synthesized in various conditions and used for lead removal from aqueous solutions. Adsorption tests were conducted in batch mode using the most efficient adsorbent, and the effects of medium pH, initial lead concentration, contact time, adsorbent dosage, and adsorption isotherms were investigated. The results showed that all composites were more efficient in lead removal compared to the fruit peels alone. The highest removal percentage was related to the composite of banana peel and Polyaniline that synthesized in the aqueous solution in the presence of 2 g·L-1 Poly ethylene glycol. This composite showed 95.96% lead adsorption at pH = 6, the contact time of 90 min, the initial lead concentration of 25 mg·L-1, and an adsorbent concentration of 8 g·L-1. Adsorption isotherm study showed that adsorption of lead by synthesized composite could be fitted by both Langmuir and Freundlich models, but the Langmuir model was more fitted than Freundlich. Besides, some characteristics of the composites, such as chemical composition (XRD analysis), structure, and morphology (SEM analysis) and functional groups (FTIR analysis), were studied.
    Separation of salidroside from the fermentation broth of engineered Escherichia coli using macroporous adsorbent resins
    Xiaocui Sun, Xue Liu, Guang-Rong Zhao
    2022, 44(4):  260-267.  doi:10.1016/j.cjche.2021.02.019
    Abstract ( 39 )   PDF (1073KB) ( 36 )  
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    Salidroside (8-O-β-D-glucoside of tyrosol), a plant-derived natural product, is used for treatment of hypoxia, fatigue and aging diseases. The availability of salidroside is restricted since it is extracted from 3-5 years old Rhodiola roots, which grow very slowly in the cold region of northern hemisphere of Earth. Our laboratory has constructed an engineered Escherichia coli and established a fermentation process to produce salidroside from glucose. In this article, nine macroporous resins from polarity to non-polarity, including NKA-9, S-8, AB-8, SP825, D101, LSA-8, LX-12, LX-18 and LX-68 resins, were tested to separate salidroside from fermentation broth. After static and dynamic experiments, the weakly polar SP825 resin had a better separation efficiency among nine resins. The adsorption kinetic and isotherm of salidroside on the SP825 resin were determined, and the pseudo-second-order kinetic model and Langmuir model could be fitted well. The effects of the pH on adsorption and ethanol concentration on desorption were investigated, and an optimal separation process was established. The adsorption for salidroside in the SP825 resin column was conducted with loading 150 ml at pH 7, and desorpted by washing 50 ml of 80% ethanol solution. Under the best process conditions, the purity and yield of salidroside in the final product were 91.6% and 74.0%, respectively. The results showed that the macroporous SP825 resin would be feasible and effective to prepare salidroside and has promising application in the downstream process of microbial fermentation.
    Characterization and structure analysis of the heterosolvate of erythromycin thiocyanate
    Yuanjie Li, Qiuxiang Yin, Meijing Zhang, Ying Bao, Baohong Hou, Jingkang Wang, Jiting Huang, Ling Zhou
    2022, 44(4):  268-274.  doi:10.1016/j.cjche.2021.04.005
    Abstract ( 29 )   PDF (5003KB) ( 45 )  
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    Erythromycin thiocyanate is widely used for the production of other macrolide antibiotics. In this work, a novel heterosolvate of this pharmaceutical compound has been obtained and characterized for the first time, which was transformed from the dihydrate form in the acetone solvent through evaporation crystallization. Thermal behavior together with compositional analysis revealed that both water and acetone molecules participated in the formation of the crystal lattice which is rarely reported before. The general chemical name of the heterosolvate may be defined as erythromycin thiocyanate sesquihydrate hemiacetonate. Furthermore, studies on solid-state spectral analysis provided strong evidence of intermolecular hydrogen bonds in heterosolvate crystals. According to the crystal structure determined by single crystal X-ray diffraction, the formation mechanism of the heterosolvate is proposed in which strong multi-hydrogen bondings between water and solute molecules form the layer structure. While acetone molecules form single-hydrogen bonds with solutes and reside in channels between layers. This well explains why acetone solvent is easy to escape from the crystal structure during desolvation.
    Investigation on the effects of fluid intensification based preconditioning process on the decarburization enhancement of fly ash
    Danlong Li, Yannan Liang, Hainan Wang, Ruoqian Zhou, Xiaokang Yan, Lijun Wang, Haijun Zhang
    2022, 44(4):  275-283.  doi:10.1016/j.cjche.2021.03.001
    Abstract ( 29 )   PDF (8321KB) ( 18 )  
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    Fly ash (FA) is a complex and abundant solid waste created by humans, and has caused environmental issues, for which flotation is an effective technique employed before its comprehensive utilization. However, the complex and hydrophilic characteristics of FA particles cannot naturally fulfill the selective separation by common flotation. Therefore, this study aims to provide an insight into fluid intensification effects on flotation to achieve the enhancement of FA surface property and decarburization. The relevant effects and mechanisms are investigated, based on the measurements of zeta potential, infrared spectroscopy, contact/wrap angle, induction time, size distribution and scanning electron microscopy–energy dispersive spectrometry. Experimental results manifested that the maximum unburned carbon recovery (73.25%) and flotation rate (0.2037 s-1) were achieved with preconditioning energy inputs of 14.23 and 6.57 W·kg-1 respectively. With increasing preconditioning energy inputs, fluid intensification effects could promote the inter-particle collision/attrition, detachment of hydrophilic existence and collector adsorption on particles. Correspondingly, absorbance of some hydrophobic and hydrophilic functional groups was strengthened and weakened respectively, which accounted for the improved interfacial properties, reflected as the increased contact and wrap angles, together with declined induction time. Overall, this article revealed the positive influences of fluid intensification based preconditioning process on rendering particle surface hydrophobic and improving separation performance.
    Evolution of copper nanowires through coalescing of copper nanoparticles induced by aliphatic amines and their electrical conductivities in polyester films
    Mingxia Tian, Aili Wang, Hengbo Yin
    2022, 44(4):  284-291.  doi:10.1016/j.cjche.2021.03.003
    Abstract ( 30 )   PDF (6990KB) ( 17 )  
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    Copper nanowires were synthesized by the wet chemical reduction method using copper sulfate as the copper precursor, aliphatic amines (methylamine, ethanediamine, 1,2-propanediamine) as the inducing reagents, and hydrazine hydrate as the reductant through the aging and reduction processes. The high-resolution transmission electron microscopy (HRTEM) images reveal that the copper nanowires were synthesized by coalescing extremely small-sized copper nanoparticles with the particle sizes of 1–6 nm in copper complex micelles. A longer aging time period favored the coalescing of the copper nanoparticles to form thinner copper nanowires in the following reduction process. The coalescing extent of copper nanoparticles in copper nanowires was highly enhanced by ethanediamine and 1,2-propanediamine as compared with that by methylamine. The copper nanowire-filled polyester films had higher electrical conductivity than the copper nanoparticle-filled ones.
    Study on environmentally friendly refrigerant R13I1/R152a as an alternative for R134a in automotive air conditioning system
    Nuochen Zhang, Yuande Dai, Linghao Feng, Biao Li
    2022, 44(4):  292-299.  doi:10.1016/j.cjche.2021.02.028
    Abstract ( 37 )   PDF (3292KB) ( 75 )  
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    Aiming at solving the problem of high global warming potential of R134a, a new mixed refrigerant R13I1/R152a (molar fraction ratio of 35:65) with no ozone depletion potential and low global warming potential was proposed as a substitute for R134a in automotive air conditioning. The computational models for the thermodynamic properties of R13I1/R152a were established by using the PR (Peng-Robinson) equation of state combined with the vdW mixing rule. Based on these models, the cycle performance of this working fluid was calculated, which was also compared with that of R134a and R1234yf under the different operating conditions. The results show that R13I1/R152a is a near azeotropic refrigerant whose temperature glide is approximately 0, and the saturated vapor pressure curve of which is equivalent to that of R134a. Moreover, compared to R134a, R13I1/R152a has an average 5.7% improvement in coefficient of performance as well as similar volumetric cooling capacity. The average coefficient of performance and volumetric cooling capacity of R13I1/R152a are significantly higher than those of R1234yf by 13.8% and 12.0%, respectively. However, the average discharge temperature of R13I1/R152a is approximately 13.3 K higher than that of R134a, but it is also within reasonable limits. Hence, the application of the proposed refrigerant R13I1/R152a in automotive air conditioning system is technically feasible.
    Modification of FCC slurry oil and deoiled asphalt for making high-grade paving asphalt
    Lingrui Cui, Jun Xu, Mannian Ren, Tao Li, Dianhua Liu, Fahai Cao
    2022, 44(4):  300-309.  doi:10.1016/j.cjche.2021.05.040
    Abstract ( 44 )   PDF (2755KB) ( 30 )  
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    With the rapid development of modern industry, high-grade paving asphalt is massively required to meet the demands for modern transportation. As one of additives, natural asphalt is indispensable since it can improve the performance of paving asphalt in all aspects. However, the application of non-renewable natural asphalt is increasingly restricted by its limited reserves. It is imperative to find alternative approaches to produce high-grade paving asphalt. Fluid catalytic cracking (FCC) slurry oil is an ideal soft component for producing paving asphalt due to its high content of aromatics and resins. However, its bad ageing resistance limits its application to only low-grade paving asphalt. In the present work, a novel approach for producing high-grade paving asphalt was investigated using chemically modified FCC slurry oil and deoiled asphalt (DOA). The FT-IR and NMR results showed that dehydrogenation and condensation reaction occurred during the ageing process. From a series of aliphatic alcohols and aldehydes, propanal was selected as a proper modifier to improve the ageing resistance of FCC slurry oil. The propanal-modified slurry oil possessed more substituted aromatic units and less aromatic hydrogen atoms than other modified slurry oils, thus showing better ageing resistance. With the increase of length of aliphatic chains in modifier, the modified slurry oil contained more and longer alkyl substituent group on aromatics. Compared with the cross-linked oil (slurry oil modified by cross-linking agent), modified slurry oil possessed similar ageing resistance but higher flowing ability. Also, the effect of operation conditions on the kinematic viscosity of modified slurry oil were investigated. Blended with modified slurry oil, the penetration ratio of asphalt product increased from 53.7 to 66.2, which met the standard of 70# paving asphalt. Both the microscopic observations and FT-IR results indicated that modification process effectively reduced the oxidation degree of asphalt product, thus increasing the ageing resistance. Consequently, with aid of this process, high-grade paving asphalt was readily produced from low value oil from downstream products of refinery, instead of the depleting natural asphalt.
    Optimization of continuous electrocoagulation-adsorption combined process for the treatment of a textile effluent
    Kamel Hendaoui, Malika Trabelsi-Ayadi, Fadhila Ayari
    2022, 44(4):  310-320.  doi:10.1016/j.cjche.2020.10.047
    Abstract ( 33 )   PDF (5435KB) ( 113 )  
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    The aims of this study is to design and optimize the functioning of a full continuous combined process based on electrocoagulaion-adsorption on crude Tunisian clay to treat a real textile effluent. The clay characterization shows that the used clay is a rich-smectite clay. The response surface methodology (RSM) technique based on Box-Behnken design (BBD) was used to optimize the process. At optimum conditions which are initial pH solution of 8.24, effluent flow rate of 0.5 L·min-1, voltage of 70 V, and added suspension of clay flow rate of 100 ml·min-1 the achieved color, chemical oxygen demand (COD) and total suspended solid (TSS) removal efficiencies were respectively 96.87%, 89.77% and 84.46% with 0.75USD·m-3 as total cost. The additional laboratory experiments at optimum conditions agree with the predicted results, which confirm the accuracy and the capability of RSM to predict results in the defined space. Finally the designed process could be a good eco-friendly alternative to treat and reuse wastewater in industrial process with reasonable cost.
    Fluidization dynamic characteristics of carbon nanotube particles in a tapered fluidized bed
    Wenjuan Bai, Dianming Chu, Yan He
    2022, 44(4):  321-331.  doi:10.1016/j.cjche.2021.03.006
    Abstract ( 32 )   PDF (5891KB) ( 74 )  
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    In this work, a tapered fluidized bed (TFB) without a distributor for fluidizing carbon nanotube (CNT) was applied for improving the dead zone, blockage, and fracture of distributor, which occurred in actual production. Experiments were performed under different superficial gas velocities, static bed heights, CNT agglomerate size, and positions of pressure probe. To obtain multi-perspective and multi-scale understanding of fluidization dynamics of gas–CNT flow in the TFB without a distributor, the standard deviation, skewness, kurtosis, wavelet decompositions and homogeneous index analysis methods were adopted. Some noticeable phenomena were observed. Particle movements including inter-particle, gas–particle and particle–wall dominate dynamic characteristics. The amplitudes of pressure fluctuations of coarse agglomerated multi-walled CNT were more sensitive to the gas velocity than that of fine agglomerated multi-walled CNT. The sensitively of energy contribution of the meso- and macro-structures was that the sensitivity of the measured position was less than the sensitivity of the energy contribution by the changes of particle size, and the sensitivity of the energy contribution by the changes of particle size was less than the energy contribution by the changes of gas velocity. The fluidization quality of coarse agglomerated multi-walled CNT was better than that of fine agglomerated multi-walled CNT, which was verified by the skewness and wavelet analysis.
    Transparent and anti-fogging AlPO4-5 films constructed by oblique oriented nano-flake crystals
    Fei Tong, Jie Gong, Liang Yu, Ming Li, Lixiong Zhang
    2022, 44(4):  332-340.  doi:10.1016/j.cjche.2021.02.004
    Abstract ( 25 )   PDF (7708KB) ( 34 )  
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    In the present work, transparent and anti-fogging AlPO4-5 films were prepared on glass substrates using a novel developed process. The process entails a simple in-situ sol–gel followed by vapor phase transport. The in-situ sol–gel process was implemented by coating the precursor sols for the synthesis of AlPO4-5 on the glass substrates successively using the spin-coating method. The films and powders scribed from the films were characterized by X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), atomic force microscope (AFM), X-ray photoelectron spectroscopy and transmission electron microscope (TEM). The unique films were composed of oblique oriented nano-flake AlPO4-5 crystals with the thickness of about 20 nm. The formation of nano-flake crystals can be ascribed to the high concentration of the precursors, resulting in the formation of a supersaturation system. The obtained films showed high antifogging performance due to the superhydrophilicity with a water contact angle of lower than 1.0°. The silicone oil contact angle was also low about 8.2°. In addition, heteroatom-substituted AlPO4-5 films showing different colors can be obtained easily by simply adding transition metal ions in the phosphate acid solution during the preparation that can extend the application of the method for different coating demand.
    Effect of additives on nickel-phosphorus deposition obtained by electroless plating: Characterization and corrosion resistance in 3%(mass) sodium chloride medium
    N. M'hanni, T. Anik, R. Touir, M. Galai, M. Ebn Touhami, E.H. Rifi, Z. Asfari, S. Bakkali
    2022, 44(4):  341-350.  doi:10.1016/j.cjche.2021.01.015
    Abstract ( 30 )   PDF (7597KB) ( 18 )  
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    Nichel-phosphorus (Ni-P) coatings are deposited on mild steel by using an electroless plating process. The effect of three calix[4]arene derivatives, namely tetra methyl ester-P-tertbutyl calix[4]arene (Calix1), tetra acid-P-tert-butyl calix[4]arene (Calix2) and tetra methyl P-tert-butyl-thicalix[4]arene ester (Calix3) on the deposition rate, the deposit composition, and the morphological surface was investigated and the study of growth mechanisms has delivered useful information about the surface properties of deposit. It is found that these additives modify the deposition rate and the nickel crystallization process. In fact, the Calix1 and Calix3 act as an accelerator, while Calix2 acts as an inhibitor for the nickel electroless. Furthermore, it is shown that the chemical bath is more stable with calix[4]arene derivatives addition and the obtained deposits are compact and adherent. It is observed also that the nickel content increases with additives. On the other hand, the X-ray diffraction showed that the orientation peaks are intensified at {1 1 1} in the presence of Calix2, confirming obtained results of EDAX spectrum. The cyclic voltammetry revealed that the tested additives strongly influence the cathodic process and slightly affect the hypophosphite oxidation. Finally, it is found that these compounds improve the anticorrosion efficiency of Ni-P coating on the mild steel substrate in 3% (mass) NaCl, where its polarization resistance increases with Calix2 and Calix3 addition.
    Construction of a Brönsted-Lewis solid acid catalyst La-PW-SiO2/SWCNTs based on electron withdrawing effect of La(III) on π bond of SWCNTs for biodiesel synthesis from esterification of oleic acid and methanol
    Qing Shu, Xinyuan Liu, Yanting Huo, Yuhui Tan, Caixia Zhang, Laixi Zou
    2022, 44(4):  351-362.  doi:10.1016/j.cjche.2021.02.002
    Abstract ( 31 )   PDF (1872KB) ( 75 )  
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    A novel solid Brönsted-Lewis acid catalyst La-PW-SiO2/SWCNTs (single-wall carbon nanotubes) was synthesized from the synergistic modification of H3PW12O40 (HPW) by single-walled carbon nanotubes functionalized with sidewall hydroxyl groups (SWCNTs–OH) and La3+ via sol–gel method. The freshly prepared catalyst was characterized by several methods, and the catalytic activity and stability of it were studied from the esterification of oleic acid and methanol. Results showed that the highest conversion of oleic acid was 93.1% (mass) and maintained as high as 88.7% (mass) after six cycles of La-PW-SiO2/SWCNTs. The high catalytic activity and stability of La-PW-SiO2/SWCNTs can be attributed to the strong electron withdrawing effect of La3+ on π bond of SWCNTs, because it can facilitate the formation of a large number of strong Lewis acid sites. Therefore, the reduction of catalytic activity of a solid acid catalyst due to the fact that hydration reaction of its Brönsted acid sites can be effectively reduced. La-PW-SiO2/SWCNTs can be an efficient and economical catalyst, because it shows good catalytic activity and stability.
    Simultaneous utilization of electro-generated O2 and H2 for H2O2 production: An upgrade of the Pd-catalytic electro-Fenton process for pollutants degradation
    Wei Zhou, Xiaoxiao Meng, Liang Xie, Junfeng Li, Yani Ding, Yanlin Su, Jihui Gao, Guangbo Zhao
    2022, 44(4):  363-368.  doi:10.1016/j.cjche.2021.01.003
    Abstract ( 22 )   PDF (3062KB) ( 30 )  
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    The Electro-Fenton (EF) process is one of the promising advanced oxidation processes (AOPs) for environmental remediation. The H2O2 yield of EF process largely determines its performance on organic pollutants degradation. Conventional Pd-catalytic EF process generates H2O2 via the combination reaction of anodic O2 and cathodic H2. However, the relatively expensive catalyst limits its application. Herein, a hybrid Pd/activated carbon (Pd/AC)-stainless steel mesh (SS) cathode (PACSS) was proposed, which enables more efficient H2O2 generation. It utilizes AC, the support of Pd catalyst, as part of cathode for H2O2 generation via 2-electron anodic O2 reduction, and SS serve as a current distributor. Moreover, H2O2 could be catalytically decomposed upon AC to generate highly reactive ·OH, which avoids the use of Fe2+. Compared with conventional Pd catalyst, H2O2 concentration obtained by PACSS cathode is 248.2% higher, the O2 utilization efficiency was also increased from 3.2% to 10.8%. Within 50 min, 26.3%, 72.5%, and 94.0% H2O2 was decomposed by Pd, AC, and Pd/AC. Fluorescence detection results implied that Pd/AC is effective upon H2O2 activation for OH generation. Finally, iron-free EF process enabled by PACSS cathode was examined to be effective for reactive blue 19 (RB19) degradation. After continuous running for 10 cycles (500 min), the PACSS cathode was still stable for H2O2 generation, H2O2 activation, and RB19 degradation, showing its potential application for organic pollutants degradation without increase in the running cost.
    Preparation and properties of Ni-W-P-TiO2 nanocomposite coatings developed by a sol-enhanced electroplating method
    Zhen He, Yu Zhou, Yuxin Wang, Pingyi Guo, Wensen Jiang, Caizhen Yao, Xin Shu
    2022, 44(4):  369-376.  doi:10.1016/j.cjche.2021.03.046
    Abstract ( 56 )   PDF (8446KB) ( 22 )  
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    Several Ni-W-P-TiO2 nanocomposite coatings were developed by the sol-enhanced electroplating method. The phase and elemental compositions of coatings were determined, and the surface and cross-section morphology were characterized. The mechanical and corrosion performance were systematically tested. The results revealed the addition of 5 ml·L-1 TiO2 sol caused a compact coating surface, while higher concentrations of TiO2 reduced the coating thickness and led to the inferior surface microstructure. The comparison in physiochemical properties of prepared coatings confirmed the superior performance of the Ni-W-P-TiO2 nanocomposite coating at 5 ml·L-1 TiO2 sol addition. Under this condition, the best mechanical properties were achieved when abrasive wear was the dominating wear-resistance mechanism, and the best corrosion resistance was obtained due to its smooth and compact surface microstructure.
    Boosting low-temperature selective catalytic reduction of NO with NH3 of V2O5/TiO2 catalyst via B-doping
    Hanghang Li, Wei Zhao, Licheng Wu, Qian Wang, Danhong Shang, Qin Zhong
    2022, 44(4):  377-383.  doi:10.1016/j.cjche.2021.04.021
    Abstract ( 34 )   PDF (4623KB) ( 36 )  
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    A series of B-doped V2O5/TiO2 catalysts has been prepared the by sol-gel and impregnation methods to investigate the influence of B-doping on the selective catalytic reduction (SCR) of NOx with NH3. X-ray diffraction, Brunauer-Emmett-Teller specific surface area, scanning electron microscope, X-ray photoelectron spectroscopy, temperature-programmed reduction of H2 and temperature-programmed desorption of NH3 technology were used to study the effect of the B-doping on the structure and NH3-SCR activity of V2O5/TiO2 catalysts. The experimental results demonstrated that the introduction of B not only improved the low-temperature SCR activity of the catalysts, but also broadened the activity temperature window. The best SCR activity in the entire test temperature range is obtained for VTiB2.0 with 2.0% doping amount of B and the NOx conversion rate is up to 94.3% at 210 ℃. The crystal phase, specific surface area, valence state reducibility and surface acidity of the active components for the as-prepared catalysts are significantly affected by the B-doping, resulting in an improved NH3-SCR performance. These results suggest that the V2O5/TiO2 catalysts with an appropriate B content afford good candidates for SCR in the low temperature window.
    Solubility and metastable zone width measurement of 2,4-diaminobenzenesulfonic acid in (H2SO4 + H2O) system
    Fanfan Shen, Lizhen Chen, Pengbao Lian, Jianlong Wang, Duanlin Cao
    2022, 44(4):  384-391.  doi:10.1016/j.cjche.2021.04.033
    Abstract ( 28 )   PDF (2547KB) ( 28 )  
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    The equilibrium solubility of 2,4-diaminobenzenesulfonic acid and super solubility as well as metastable zone width were measured in (H2SO4 + H2O) system by the laser dynamic method at elevate temperature range from 298.15 K to 338.15 K. 2,4-Diaminobenzenesulfonic acid solubility dependence on the temperature and solvent composition were correlated by the modified Apelblat equation, (CNIBS)/Redlich-Kister model and Jouyban-Acree model. The correlated results by three correlation models were in good accord with the experimental values according to relative average deviations (RD), root-mean-square deviations (RMSD), and correlation coefficients (R2). The metastable zone width increased with temperature and sulfuric acid content. The dissolution enthalpy, dissolution entropy and the Gibbs energy were calculated from the experimental values, which indicated that dissolution process of the 2,4-diaminobenzenesulfonic acid was endothermic. The solubility and calculation models of 2,4-diaminobenzenesulfonic acid in (sulfuric acid + water) system could provide the basic data to the crystallization and purifying of the 2,4-diaminobenzenesulfonic acid.
    A facile preparation of hausmannite as a high-performance catalyst for toluene combustion
    Qi Liu, Gao Cheng, Ming Sun, Weixiong Yu, Xiaohong, Zeng, Shichang Tang, Yongfeng li, Lin Yu
    2022, 44(4):  392-401.  doi:10.1016/j.cjche.2021.02.026
    Abstract ( 59 )   PDF (10911KB) ( 19 )  
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    Mesoporous transition metal oxide catalysts are well-used in the elimination of volatile organic compounds. In this study, we developed an efficient method for the preparation of mesoporous-Mn3O4 (m-Mn3O4) without the use of templates or surfactants. In this method, KCl protects oxygen defects on the surface of fresh Mn3O4 crystallites. m-Mn3O4 shows higher ameliorative catalytic activity than bulk-Mn3O4 (b-Mn3O4) and calcined-Mn3O4 (c-Mn3O4), achieving toluene catalytic oxidation of T10 and T90 (the temperature at a conversion rate of about 10% and 90%) at 191 ℃ and 230 ℃, respectively (WHSV = 40,000 ml·g-1·h-1). Based on various characterizations, the prepared m-Mn3O4 has large specific surface area and abundant oxygen defects, and thus can provide more surface active sites, which give it superior toluene combustion activity.
    Simultaneous synthesis of heat-integrated water networks by a nonlinear program: Considering the wastewater regeneration reuse
    Fangyou Yan, Wei Li, Jinli Zhang
    2022, 44(4):  402-411.  doi:10.1016/j.cjche.2020.11.044
    Abstract ( 30 )   PDF (3230KB) ( 30 )  
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    Heat-integrated water network synthesis (HIWNS) has received considerable attention for the advantages of reducing water and energy consumptions. HIWNS is effective in water and energy sustainability. Mixed integer non-linear programming (MINLP) is usually applied in HIWNS. In this work, a novel nonlinear programming (NLP) was proposed for HIWNS by considering wastewater reuse and wastewater regeneration reuse. Integer variables are changed to non-linear equation by the methods for identifying stream roles and denoting the existence of process matches. The model is tested by examples with single and multiple regeneration unit problems. The testing results showed that the NLP is an alternative method for HIWNS with wastewater reuse and regeneration reuse.
    Computational fluid dynamics simulation of gas dispersion in complex facilities using Kit Fox field experiments: Validation and statistical evaluation
    Narjes Hemati Alam, Eslam Kashi, Razieh Habibpour
    2022, 44(4):  412-423.  doi:10.1016/j.cjche.2020.11.043
    Abstract ( 24 )   PDF (10525KB) ( 15 )  
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    Gas release and its dispersion is a major concern in chemical industries. In order to manage and mitigate the risk of gas dispersion and its consequences, it is necessary to predict gas dispersion behavior and its concentration at various locations upon emission. Therefore, models and commercial packages such as Phast and ALOHA have been developed. computational fluid dynamics (CFD) can be a useful tool to simulate gas dispersion in complex areas and conditions. The validation of the models requires the employment of the experimental data from filed and wind tunnel experiments. It appears that the use of the experimental data to validate the CFD method that only includes certain monitor points and not the entire domain can lead to unreliable results for the intended areas of concern. In this work, some of the trials of the Kit Fox field experiment, which provided a wide-range database for gas dispersion, were simulated by CFD. Various scenarios were considered with different mesh sizes, physical conditions, and types of release. The results of the simulations were surveyed in the whole domain. The data matching each scenario was varied by the influence of the dominant displacement force (wind or diffusivity). Furthermore, the statistical parameters suggested for the heavy gas dispersion showed a dependency on the lower band of gas concentration. Therefore, they should be used with precaution. Finally, the results and computation cost of the simulation could be affected by the chosen scenario, the location of the intended points, and the release type.
    Numerical investigation of grooves effects on the thermal performance of helically grooved shell and coil tube heat exchanger
    Mehdi Miansari, Mehdi Rajabtabar Darvishi, Davood Toghraie, Pouya Barnoon, Mojtaba Shirzad, As'ad Alizadeh
    2022, 44(4):  424-434.  doi:10.1016/j.cjche.2021.05.038
    Abstract ( 29 )   PDF (14366KB) ( 21 )  
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    Heat exchangers are integral parts of important industrial units such as petrochemicals, medicine and power plants. Due to the importance of systems energy consumption, different modifications have been applied on heat exchangers in terms of size and structure. In this study, a novel heat exchanger with helically grooved annulus shell and helically coiled tube was investigated by numerical simulation. Helically grooves with the same pitch of the helical coil tube and different depth are created on the inner and outer wall of annulus shell to improve the thermal performance of heat exchanger. In the first section, thermal performance of the shell and coil heat exchanger with the helical grooves on its outer shell wall was compared with same but without helical grooves. At the second section, helically grooves created on both outer and inner wall of the annulus shell with different groove depths. The results showed that the heat exchanger with grooves on both inner and outer shell wall has better thermal performance up to 20% compared to the heat exchanger with grooves on only outer shell wall. The highest thermal performance achieves at lower flow rates and higher groove depths whereas the pressure drop did not increase significantly.
    Gas cyclone-liquid jet absorption separator used for treatment of tail gas containing HCl in titanium dioxide industry
    Liwang Wang, Hualin Wang, Liang Ma, Zhanghuang Yang, Erwen Chen
    2022, 44(4):  435-446.  doi:10.1016/j.cjche.2021.01.010
    Abstract ( 28 )   PDF (10500KB) ( 42 )  
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    In the titanium dioxide industry, there is a lack of a low-cost and high-efficiency treatment method for chloride containing tail gas. In this paper, the removal of HCl from the titanium dioxide industry by gas cyclone-liquid jet separator was studied, while Ca(OH)2, Na2CO3, NaOH solution, and water were used as absorbents. This paper investigated the influence of gas cyclone-liquid jet separator’s various process parameters on the removal rate of hydrogen chloride gas. The mechanism of mass transfer in the process of removing hydrogen chloride was discussed, and the effect and feasibility of HCl gas removal in the gas cyclone-liquid jet absorption separator were studied. The results showd that the removal efficiency of hydrogen chloride maintained above 95%, up to 99.9%, and the total mass transfer coefficient reached 0.28 mol·m-3·s-1·kPa-1. Under the same conditions, the absorption effect and total mass transfer coefficient of weak basic absorption liquid can be greatly improved by increasing the flow rate of absorption liquid, but the absorption effect and total mass transfer coefficient of strong alkaline absorption liquid can’t be improved obviously. The larger the inlet gas volume, the higher the gas concentration, the lower the absorption efficiency and the lower the total volumetric mass transfer coefficient.
    Surfactant-assisted removal of 2,4-dichlorophenol from soil by zero-valent Fe/Cu activated persulfate
    Ling Xu, Ji Li, Wenbin Zeng, Kai Liu, Yibing Ma, Liping Fang, Chenlu Shi
    2022, 44(4):  447-455.  doi:10.1016/j.cjche.2021.03.031
    Abstract ( 34 )   PDF (5906KB) ( 28 )  
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    The organic compounds contaminated soil substantially threatens the growth of plants and food safety. In this study, we synthesis zero-valent bimetallic Fe/Cu catalysts for the degradation of 2,4-dichlorophenol (DCP) in soils with persulfate (PS) in combination of organic surfactants and exploring the main environmental impact factors. The kinetic experiments show that the 5% (mass) dosage of Fe/Cu exhibits a higher degradation efficiency (86%) of DCP in soils, and the degradation efficiency of DCP increases with the increase of the initial PS concentration. Acidic conditions are favorable for the DCP degradation in soils. More importantly, the addition of Tween-80, and Triton-100 can obviously desorb DCP from the soil surface, which enhances the degradation efficiency of DCP in soils by Fe/Cu and PS reaction system. Furthermore, the Quenching experiments demonstrate that SO4-· and ·OH are the predominant radicals for the degradation of DCP during the Fe/Cu and PS reaction system as well as non-radical also exist. The findings of this work provide an effective method for remediating DCP from soils.
    Visualization on electrified micro-jet instability from Taylor cone in electrohydrodynamic atomization
    Shiqi Yang, Zhentao Wang, Qian Kong, Bin Li, Junfeng Wang
    2022, 44(4):  456-465.  doi:10.1016/j.cjche.2021.03.005
    Abstract ( 24 )   PDF (6064KB) ( 37 )  
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    The cone-jet in electrohydrodynamic atomization has been widely applied into numerous industrial fields owing to micro-sized drops with narrow distribution and high charge. The electrified jet emits from a single capillary sheathed with quartz tube is visualized versus operating parameters and physical properties, and breakup instabilities are also discussed. The range of operating parameters for a steady cone-jet broadens, as well as the minimum flow rate. Taylor cone angle decreases with an increase in flow rate, while increases as electric potential increasing. The jet breakup length decreases with an increase in flow rate and conductivity, while increases as electric potential increasing. The diffusion angle increases as flow rate increasing, while decrease as electric potential and conductivity increasing. Much clearer whipping instabilities are observed with an increase in “electro-Weber” number and conductivity. The completion in disturbance or/and suppression from axial and radial stresses, drag force dominates the variation. Meanwhile, for a large flow rate, the transition from varicose instabilities to whipping instabilities is found. The whipping instabilities are clearly observed for high conductivity due to much more free ions in liquid. For much higher conductivity, an intermittent electrified jet appears and shows an umbrella plume, and breakup length sharply shortens.
    Theoretical and experimental assessment of a novel method to establish the complete measurement range of the calorimeter and its limit of detection and quantification
    Vesna Krsti?
    2022, 44(4):  466-473.  doi:10.1016/j.cjche.2021.08.019
    Abstract ( 24 )   PDF (1982KB) ( 116 )  
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    For determining the accuracy of a calorimeter over the instrument’s entire measuring range, a novel method has been established. For this new approach, (a) benzoic acid (C6H5CO2H) as a certified reference material (CRM), (b) SiO2 and (c) a mixture of CRM benzoic acid and SiO2 have been used. To illustrate the essential difference between 1) the novel analytical method for control of the entire measurement range and 2) the calorimeter calibration, both applications of benzoic acid (BA) have been demonstrated. An experimental result showed that BA was successfully used to check the whole calorimeter measurement range. The results also showed that the same new method was successfully applied to determine the limit of detection and quantification. A new instrument testing process and a new measurement technique have thus been established. In this way, the cost of using CRM to control the accuracy of measuring the entire measuring range of the calorimeter, as shown in this paper, is minimized. The requirements of the ISO/IEC 17025:2017 standard are satisfied. ISO/IEC 17025:2017, together with ISO 9001:2015 (quality management systems), ISO 14001:2015 (relate to environmental protection) and ISO 45001:2018 (occupational safety), constitute an integrated quality system by which a testing laboratory may also accredit.
    Measurement and correlation of the solubility of sodium acetate in eight pure and binary solvents
    Xi Wu, Shuaishuai Yang, Shiming Xu, Xinjie Zhang, Yujie Ren
    2022, 44(4):  474-484.  doi:10.1016/j.cjche.2021.06.029
    Abstract ( 47 )   PDF (1497KB) ( 239 )  
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    The knowledge of solubility of a salt in either the pure solvent or blend solvent is of great importance for studying or operating the crystallization, extraction, and distillation processes. The solubility of sodium acetate (NaAc) in four pure solvents (water, ethanol, acetic acid and 2,2,2-trifluoroethanol) and four binary solvents (water–ethanol, water-acetic acid, acetic acid–ethanol, and acetic acid-ethyl acetate) were measured by using the laser dynamic method at temperatures from 288.15 K to 338.15 K at 0.1 MPa. The results showed that the solubility of NaAc was influenced by either the solution temperature or solvent composition. The aqueous sodium acetate solution possessed the maximal solubility under the experimental conditions. The solubility of NaAc in 2,2,2-trifluoroethanol was found to be decreased with the increase of the solution temperature. While, the solubilities of NaAc in other seven solvents increased as the solution temperature was elevated. Besides, five correlation models, including the van't Hoff model, modified Apelblat model, Yaws model, λh model, and modified Apelblat-Jouyban-Acree model were used to correlate the solubility data of those sodium acetate solutions with acceptable deviation, respectively. Finally, van't Hoff analysis method was selected to analyze the change law of thermodynamic properties of a salt during the dissolution process.
    Computational study of bubble coalescence/break-up behaviors and bubble size distribution in a 3-D pressurized bubbling gas-solid fluidized bed of Geldart A particles
    Teng Wang, Zihong Xia, Caixia Chen
    2022, 44(4):  485-496.  doi:10.1016/j.cjche.2021.03.040
    Abstract ( 37 )   PDF (10943KB) ( 18 )  
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    A computational study was carried out on bubble dynamic behaviors and bubble size distributions in a pressurized lab-scale gas-solid fluidized bed of Geldart A particles. High-resolution 3-D numerical simulations were performed using the two-fluid model based on the kinetic theory of granular flow. A fine-grid, which is in the range of 3–4 particle diameters, was utilized in order to capture bubble structures explicitly without breaking down the continuum assumption for the solid phase. A novel bubble tracking scheme was developed in combination with a 3-D detection and tracking algorithm (MS3DATA) and applied to detect the bubble statistics, such as bubble size, location in each time frame and relative position between two adjacent time frames, from numerical simulations. The spatial coordinates and corresponding void fraction data were sampled at 100 Hz for data analyzing. The bubble coalescence/break-up frequencies and the daughter bubble size distribution were evaluated by using the new bubble tracking algorithm. The results showed that the bubble size distributed non-uniformly over cross-sections in the bed. The equilibrium bubble diameter due to bubble break-up and coalescence dynamics can be obtained, and the bubble rise velocity follows Davidson’s correlation closely. Good agreements were obtained between the computed results and that predicted by using the bubble break-up model proposed in our previous work. The computational bubble tracking method showed the potential of analyzing bubble motions and the coalescence and break-up characteristics based on time series data sets of void fraction maps obtained numerically and experimentally.
    Non-equilibrium thermodynamic analysis of coupled heat and moisture transfer across a membrane
    Zhijie Shen, Jingchun Min
    2022, 44(4):  497-506.  doi:10.1016/j.cjche.2021.02.020
    Abstract ( 26 )   PDF (6883KB) ( 21 )  
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    Non-equilibrium thermodynamics theory is used to analyze the transmembrane heat and moisture transfer process, which can be observed in a membrane-type total heat exchanger (THX). A theoretical model is developed to simulate the coupled heat and mass transfer across a membrane, total coupling equations and the expressions for the four characteristic parameters including the heat transfer coefficient, molar-driven heat transfer coefficient, thermal-driven mass transfer coefficient, and mass transfer coefficient are derived and provided, with the Onsager’s reciprocal relation being confirmed to verify the rationality of the model. Calculations are conducted to investigate the effects of the membrane property and air state on the coupling transport process. The results show that the four characteristic parameters directly affect the transmembrane heat and mass fluxes: the heat and mass transfer coefficients are both positive, meaning that the temperature difference has a positive contribution to the heat transfer and the humidity ratio difference has a positive contribution to the mass transfer. The molar-driven heat transfer and thermal-driven mass transfer coefficients are both negative, implying that the humidity ratio difference acts to reduce the heat transfer and the temperature difference works to diminish the mass transfer. The mass transfer affects the heat transfer by 1%–2% while the heat transfer influences the mass transfer by 7%–14%. The entropy generation caused by the temperature difference-induced heat transfer is much larger than that by the humidity difference-induced mass transfer.
    Modeling and simulation of material distribution in the sequential co-injection molding process
    Qingsheng Liu, Youqiong Liu, Chuntao Jiang
    2022, 44(4):  507-520.  doi:10.1016/j.cjche.2021.01.005
    Abstract ( 36 )   PDF (11888KB) ( 20 )  
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    In co-injection molding, the properties and distribution of polymers will affect the application of products. The focus of this work is to investigate the effect of molding parameters on the skin/core material distribution based on three-dimensional (3-D) flow and heat transfer model for the sequential co-injection molding process, and the flow behaviors and material distributions of skin and core melts inside a slightly complex cavity (dog-bone shaped cavity) are predicted numerically. The governing equations of fluids in mold are solved by finite volume method and Semi-Implicit Method for Pressure Linked Equations (SIMPLE) algorithm on collocated meshes, and the domain extension technique is employed in numerical method for this cavity to assure that the numerical algorithm is implemented successfully. The level set transport equation which is used to trace the free surfaces in co-injection molding is discretized and solved by the 5th-order Weighted Essentially Non-Oscillatory (WENO) scheme in space and 3rd-order Total Variation Diminishing Runger-Kutta (TVD-R-K) scheme in time respectively. Numerical simulations are conducted under various volume fraction of core melt, skin and core melt temperatures, skin and core melt flow rates. The predicted results of material distribution in length, width and thickness directions are in close agreement with the experimental results, which indicate that volume fraction of core melt, core melt temperature and core melt flow rate are principal factors that have a significant influence on material distribution. Numerical results demonstrate the effectiveness of the 3-D model and the corresponding numerical methods in this work, which can be used to predict the melt flow behaviors and material distribution in the process of sequential co-injection molding.
    A new approach for correlating of H2S solubility in [emim][Lac], [bmim][ac] and [emim][pro] ionic liquids using two-parts combined models
    Alireza Afsharpour
    2022, 44(4):  521-527.  doi:10.1016/j.cjche.2020.11.046
    Abstract ( 31 )   PDF (2604KB) ( 28 )  
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    Two bi-part combined models containing reaction equilibrium thermodynamic model and an equation of state (EoS) including cubic plus association (CPA) or modified Soave-Redlich-Kwong (SRK), were employed to correlate H2S solubility in ionic liquids [emim][Lac], [bmim][Ac] and [emim][Pro]. RETM and CPA/mSRK are responsible for chemical and phase equilibria calculations, respectively. The RETM defines a complex formation reaction between an H2S and two IL molecules into the liquid phase so that a complex in the form of H2S(IL)2 is probable to produce. On the other side, CPA/mSRK EoSs perform phase equilibria computations to find pressure and vapor phase concentrations. In the case of CPA, both of H2S and the ionic liquids were considered as self-associating components which pursue 4C and 2B schemes, respectively. This model computes the pure IL parameters using experimental density data. In this work, critical properties were estimated through the modified Lydersen-Joback-Reid method, Eotvos and Guggenheim relations. Afterward, the binary systems were investigated by applying RETM. CPA presents average absolute deviations (AADs) equal to 2.41%, 13.42% and 3.52% for [emim][Lac], [bmim][Ac], and [emim][Pro], respectively. Moreover, the AADs obtained by mSRK are 3.75%, 5.07%, and 6.06%, respectively. As it is evident from the results, the combination of RETM with both CPA and mSRK EoSs will result in good correlation accuracy.
    A coupled CFD simulation approach for investigating the pyrolysis process in industrial naphtha thermal cracking furnaces
    Mohsen Rezaeimanesh, Ali Asghar Ghoreyshi, S.M. Peyghambarzadeh, Seyed Hassan Hashemabadi
    2022, 44(4):  528-542.  doi:10.1016/j.cjche.2021.03.028
    Abstract ( 30 )   PDF (5992KB) ( 101 )  
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    In the steam thermal cracking of naphtha, the hydrocarbon stream flows inside tubular reactors and is exposed to flames of a series of burners in the firebox. In this paper, a full three-dimensional computational fluid dynamics (CFD) model was developed to investigate the process variables in the firebox and reactor coil of an industrial naphtha furnace. This comprehensive CFD model consists of a standard k-ε turbulence model accompanied by a molecular kinetic reaction for cracking, detailed combustion model, and radiative properties. In order to improve the steam cracking performance, the model is solved using a proposed iterative algorithm. With respect to temperature, product yield and specially propylene-to-ethylene ratio (P/E), the simulation results agreed well with industrial data obtained from a mega olefin plant of a petrochemical complex. The deviation of P/E results from industrial data was less than 2%. The obtained velocity, temperature, and concentration profiles were used to investigate the residence time, coking rate, coke concentration, and some other findings. The coke concentration at coil exit was 1.9 × 10-3 %(mass) and the residence time is calculated to be 0.29 s. The results can be used as a scientific guide for process engineers.