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Table of Content
28 November 2021, Volume 39 Issue 11
    Measurement methods of particle size distribution in emulsion polymerization
    Shuaifeng Zhang, Qinghua Zhang, Jianzhuang Shang, Zaisha Mao, Chao Yang
    2021, 39(11):  1-15.  doi:10.1016/j.cjche.2021.03.007
    Abstract ( 85 )   PDF (3445KB) ( 303 )  
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    The particle size distribution of polymer always develops in emulsion polymerization systems, and certain key phenomena/mechanisms as well as properties of the final product are significantly affected by this distribution. This review mainly focuses on the measurement methods of particle size distribution rather than average particle size during the emulsion polymerization process, including the existing off-line, on-line, and in-line measurement methods. Moreover, the principle, resolution, performance, advantages, and drawbacks of various methods for evaluating particle size distribution are contrasted and illustrated. Besides, several possible development directions or solutions of the in-line measurement technology are explored
    A panoramic view of Li7P3S11 solid electrolytes synthesis, structural aspects and practical challenges for all-solid-state lithium batteries
    Muhammad Khurram Tufail, Niaz Ahmad, Le Yang, Lei Zhou, Muhammad Adnan Naseer, Renjie Chen, Wen Yang
    2021, 39(11):  16-36.  doi:10.1016/j.cjche.2021.09.021
    Abstract ( 66 )   PDF (25122KB) ( 115 )  
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    The development of an inorganic electrochemical stable solid-state electrolyte is essentially responsible for future state-of-the-art all-solid-state lithium batteries (ASSLBs). Because of their advantages in safety, working temperature, high energy density, and packaging, ASSLBs can develop an ideal energy storage system for modern electric vehicles (EVs). A solid electrolyte (SE) model must have an economical synthesis approach, exhibit electrochemical and chemical stability, high ionic conductivity, and low interfacial resistance. Owing to its highest conductivity of 17 mS·cm-1, and deformability, the sulfide-based Li7P3S11 solid electrolyte is a promising contender for the high-performance bulk type of ASSLBs. Herein, we present a current glimpse of the progress of synthetic procedures, structural aspects, and ionic conductivity improvement strategies. Structural elucidation and mechanistic approaches have been extensively discussed by using various characterization techniques. The chemical stability of Li7P3S11 could be enhanced via oxide doping, and hard and soft acid/base (HSAB) concepts are also discussed. The issues to be undertaken for designing the ideal solid electrolytes, interfacial challenges, and high energy density have been discoursed. This review aims to provide a bird's eye view of the recent development of Li7P3S11-based solid-state electrolyte applications and explore the strategies for designing new solid electrolytes with a target-oriented approach to enhance the efficiency of high energy density all-solid-state lithium batteries.
    Technology for recycling and regenerating graphite from spent lithium-ion batteries
    Chenxing Yi, Lijie Zhou, Xiqing Wu, Wei Sun, Longsheng Yi, Yue Yang
    2021, 39(11):  37-50.  doi:10.1016/j.cjche.2021.09.014
    Abstract ( 89 )   PDF (21148KB) ( 145 )  
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    With the annual increase in the amount of lithium-ion batteries (LIBs), the development of spent LIBs recycling technology has gradually attracted attention. Graphite is one of the most critical materials for LIBs, which is listed as a key energy source by many developed countries. However, it was neglected in spent LIBs recycling, leading to pollution of the environment and waste of resources. In this paper, the latest research progress for recycling of graphite from spent LIBs was summarized. Especially, the processes of pretreatment, graphite enrichment and purification, and materials regeneration for graphite recovery are introduced in details. Finally, the problems and opportunities of graphite recycling are raised.
    Fluid Dynamics and Transport Phenomena
    Experimental investigation of dynamic mass transfer during droplet formation using micro-LIF in a coaxial microchannel
    Zhuo Chen, Qiqiang Xiong, Shaowei Li, Yundong Wang, Jianhong Xu
    2021, 39(11):  51-58.  doi:10.1016/j.cjche.2021.04.030
    Abstract ( 54 )   PDF (5139KB) ( 262 )  
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    The mass transfer of Rhodamine 6G from the droplet to the continuous phase in a coaxial micro-channel is studied using micro-LIF (Laser-Induced Fluorescence). The mass distribution inside droplet is measured and visualized. The experimental results affirm that there exists the internal circulation inside the droplet and it could enhance the convective mass transfer. The stagnant center of vortices is also observed. The extraction fraction could reach 40%-80%. In order to establish the mass transfer model, different flow rates of the dispersed and continuous phase are adopted. The high continuous phase flow rate and low dispersed phase flow rate are both beneficial to enhance mass transfer by expediting the internal circulation. A modified mass transfer model is found to calculate the extraction fraction. A good agreement between the model and experiment in various conditions demonstrates that the mass transfer model in this work is reliable and feasible.
    Hydrodynamics and mass transfer performance analysis of flow-guided trapezoid spray packing tray
    Shuo Yang, Jilong Zhang, Jiaxing Xue, Qingpeng Wu, Qunsheng Li, Hongkang Zhao, Liqun Zhang
    2021, 39(11):  59-67.  doi:10.1016/j.cjche.2020.10.046
    Abstract ( 46 )   PDF (5213KB) ( 130 )  
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    Distillation is the most common separation technology utilized in the petroleum and chemistry industries. Due to the wide usage of the distillation column, even a small improvement in performance may result in significant energy cost savings. Aiming to improve the hydrodynamics and mass transfer performance, the flow-guided trapezoid spray-packing tray (FTS-PT) was designed by combining flow-guided holes and trapezoidal caps with structured packing. And the experimental measurements of the FTS-PT, including pressure drop, clear liquid height, weeping, entrainment, and tray efficiency, were conducted in a 500 mm diameter plexiglass column with the air-water-oxygen system. Moreover, the performance of the FTS-PT was compared with that of new vertical sieve tray (New VST) and F1 valve tray. The results show that FTS-PT has a significant advantage in pressure drop, entrainment, and capacity. Furthermore, the calculation model of the pressure drop was derived and used for the FTS-PT with a relative deviation of less than 5%.
    Separation Science and Engineering
    Mechanism transformation of cyclohexene-thiophene competitive adsorption in FAU zeolite
    Pei Xue, Meng Zheng, Longwei Wang, Liyuan Cao, Liang Zhao, Jinsen Gao, Chunming Xu
    2021, 39(11):  68-78.  doi:10.1016/j.cjche.2020.12.024
    Abstract ( 50 )   PDF (12812KB) ( 267 )  
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    Competition of hydrocarbon compounds with sulfides in gasoline has caused a not very high selectivity of sulfides in adsorption desulfurization so far, resulting in a reduction of catalyst lifetime as well as more sulfur oxide emissions. Tostudy the whole competitive process changing with the increase of the loading, the dynamic competition adsorption mechanism of cyclohexene and thiophene in siliceous faujasite (FAU) zeolite was analyzed by the Monte Carlo simulation. The results showed that with the increase of the loading, thiophene and cyclohexene had different performances before and after the inflection point of 40 molecule/UC. The adsorbates weredistributed ideally at optimal sites during the stage that occurredbefore the inflection point, which is called the "optimal-displacement adsorption" stage. When approachingthe inflection point, the competition became apparent and the displacement appeared accordingly, some thiophene molecules at S sites (refers to the sites inside the supercages) were displaced by cyclohexene. After the inflection point, the concentration of adsorbates at W sites (refers to the 12-membered ring connecting the supercages) was significantly reduced, whereas the adsorbates at S sites got more concentrated. The stage some cyclohexene molecules displaced by thiophene and inserted into the center of the supercage can be named as the "insertion-displacement adsorption" stage, and both the adsorption behavior and the competitive relationship became localized when the adsorption amount became saturated. This shift in the competitive adsorption mechanism was due to the sharp increase of interaction energy between the adsorbates. Besides, the increase in temperature and ratio of Si/Al will allow the adsorbates, especially thiophene molecules to occupy more adsorption sites, and it is beneficial to improve the desulfurization selectivity.
    Functional graphene oxide nanosheets modified with cyclodextrins for removal of Bisphenol A from water
    Zhi-Hao Chen, Zhuang Liu, Lei Zhang, Quan-Wei Cai, Jia-Qi Hu, Wei Wang, Xiao-Jie Ju, Rui Xie, Liang-Yin Chu
    2021, 39(11):  79-87.  doi:10.1016/j.cjche.2021.02.018
    Abstract ( 49 )   PDF (8000KB) ( 112 )  
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    A novel type of functional graphene oxide nanosheets (GNs) modified with β-cyclodextrins (β-CDs) have been developed by coating dopamine-functionalized cyclodextrin (DACD) molecules on GNs for removing Bisphenol A (BPA) molecules from water. The DACD molecules with both β-CD groups for achieving adsorption property and dopamine (DA) groups for achieving adhesion property are synthesized by grafting DA onto carboxymethyl-β-cyclodextrin (CmβCD). The proposed DACD molecules can be firmly coated on the surfaces of various inorganic and organic substrates. Due to the large specific surface area of GNs, DACD-coated GNs (DACD@GNs) are proposed for efficient adsorption separation of BPA molecules from water. Due to the host-gust complexation between the BPA molecules in water and β-CDs on DACD@GNs, the fabricated DACD@GNs exhibit excellent adsorption performances. The adsorption kinetics can be explained via the pseudo-second-order model effectively. The experimental adsorption capacity of DACD@GNs is 11.29 mg·g-1 for BPA. Furthermore, after the adsorption process, the DACD@GNs can be easily separated from aqueous solutions via vacuum filtration with porous membranes, and then regenerated by simply washing with ethanol. The proposed strategy in this study can be used for effectively functionalizing the surfaces of various substrates with functional β-CDs, which is highly promising in applications in the field of adsorption separations, especially water treatments.
    Selective adsorption of SF6 in covalent- and metal-organic frameworks
    Xianqiang Zheng, Yanlong Shen, Shitao Wang, Ke Huang, Dapeng Cao
    2021, 39(11):  88-95.  doi:10.1016/j.cjche.2021.03.010
    Abstract ( 49 )   PDF (12718KB) ( 176 )  
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    Sulfur hexafluoride (SF6) is an extremely severe greenhouse gas. It is an urgently important mission to find excellent candidates for selective adsorption of SF6, in order to reduce the emission of SF6 facilities. Here, we adopt the molecular simulation method to systematically explore the selective adsorption of SF6 in 22 kinds of representative covalent-and metal-organic frameworks. Results indicate that COF-6 is a promising candidate for the SF6 adsorption at low pressure P<20 kPa because of its small pore size, while MOF-180 and PAF-302 are excellent candidates at high pressure P=2×103 kPa due to their large Brunauer-Emmett-Teller specific surface area (BET-SSA) and pore volumes. For the two cases of the power industry (XSF6=0.1) and the semiconductor industry (XSF6=0.002) environments, COF-6 and ZIF-8 are fairly promising candidates for selective adsorption of SF6 from the SF6/N2 mixtures, because they not only present the high selectivity, but also the large adsorption capacity at ambient environment, which can be considered as potential adsorbents for selective adsorption of SF6 at ambient conditions.
    Monitoring the spontaneous wetting process of hydrophobic microporous membrane assisted by alternating current impedance spectroscopy
    Juntian Xiao, Qian Sun, Liying Liu, Zhongwei Ding
    2021, 39(11):  96-102.  doi:10.1016/j.cjche.2020.08.055
    Abstract ( 41 )   PDF (3309KB) ( 99 )  
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    In the process of membrane absorption, spontaneous wetting of hydrophobic microporous membrane causes membrane modification and increases membrane phase mass transfer resistance, which have attracted wide interest. However, due to the limitations of previous testing methods, the study of the spontaneous membrane wetting process is limited. Herein, we present a method for monitoring spontaneous membrane wetting by measuring its alternating current (AC) impedance. The impedance tests of the PVDF flat membranes and hollow fiber membranes were conducted in a two-electrode system. The results of equivalent circuit fitting indicate that the impedance value of the unwetted membrane is about 1.02×1010 Ω, which is close to the theoretical value of 1.4×1010 Ω, and this method can quantify the electrochemical impedance value of membranes with different degrees of spontaneous wetting. In addition, a method of impedance test for real-time monitoring of spontaneous wetting was designed. During the experiment, the timeliness and continuity of this method are confirmed with exact judgment under different conditions. In future work, the impedance data will be used to build model to predict the percentage of membrane wetting degree.
    Selective adsorption behavior of ion-imprinted magnetic chitosan beads for removal of Cu(II) ions from aqueous solution
    Licheng Ma, Qi Zheng
    2021, 39(11):  103-111.  doi:10.1016/j.cjche.2020.09.030
    Abstract ( 46 )   PDF (1563KB) ( 129 )  
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    Heavy metal ion is one of the major environmental pollutants. In this study, a Cu(II) ions imprinted magnetic chitosan beads are prepared to use chitosan as functional monomer, Cu(II) ions as template, Fe3O4 as magnetic core and epichlorohydrin and glutaraldehyde as crosslinker, which can be used for removal Cu(II) ions from wastewater. The kinetic study shows that the adsorption process follows the pseudo-second-order kinetic equations. The adsorption isotherm study shows that the Langmuir isotherm equation best fits for the monolayer adsorption processes. The selective adsorption properties are performed in Cu(II)/Zn(II), Cu(II)/Ni(II), and Cu(II)/Co(II) binary systems. The results shows that the IIMCD has a high selectivity for Cu(II) ions in binary systems. The mechanism of IIMCD recognition Cu(II) ions is also discussed. The results show that the IIMCD adsorption Cu(II) ions is an enthalpy controlled process. The absolute value of ΔH (Cu(II)) and ΔS(Cu(II)) is greater than ΔH (Zn(II), Ni(II), Co(II)) and ΔS (Zn(II), Ni(II), Co(II)), respectively, this indicates that the Cu(II) ions have a good spatial matching with imprinted holes on IIMCD. The FTIR and XPS also demonstrates the strongly combination of function groups on imprinted holes in the suitable space position. Finally, the IIMCD can be regenerated and reused for 10 times without a significantly decreasing in adsorption capacity. This information can be used for further application in the selective removal of Cu(II) ions from industrial wastewater.
    Polyamide-baghouse dust nanocomposite for removal of methylene blue and metals: Characterization, kinetic, thermodynamic and regeneration
    Abdullah A. Basaleh, Muhammad H. Al-Malack, Tawfik A. Saleh
    2021, 39(11):  112-125.  doi:10.1016/j.cjche.2020.08.050
    Abstract ( 46 )   PDF (11697KB) ( 12 )  
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    In this research, polyamide modified baghouse dust nanocomposite (PMBHD) was synthesized from steel industry waste using the interfacial polymerization technique. Adsorption capacities of the PMBHD were examined for the uptake of cadmium Cd (II), lead Pb (II), and methylene blue MB from simulated solutions. The effects of different operational factors of the adsorption, including contact time, pH, adsorbent dosage, initial concentration, and temperature, were investigated. The obtained results revealed that the equilibrium data of MB, Pb (II), and Cd (II) were best fitted to Dubinin-Radushkevich, Langmuir, and Freundlich isotherm. Maximum removal uptake was found to be 6.08, 119, and 234 mg·g-1, whereas maximum removal efficiencies of 90%, 99.8%, and 98% were achieved for MB, Pb (II), and Cd (II). Adsorption kinetics of MB and metals well-fitted to the pseudo-second-order kinetic. The characterization results showed the presence of polymeric chain on the surface of the PMBHD. The thermodynamic study revealed that the values of the free energy ΔG for Pb (II) and Cd (II) were found to be negative, which indicates spontaneous, energetic, and favorable adsorption. While for MB removal, positive values of (ΔG) were noticed, which implies that the adsorption was unfavorable. The proposed mechanism for the adsorption of MB and metals on the PMBHD showed that the dominating mechanism is physisorption. The adsorption/desorption results verified the high reusability of the PMBHD for adsorption of MB and metals.
    Catalysis, Kinetics and Reaction Engineering
    Enhancing the activity of MoS2/SiO2-Al2O3 bifunctional catalysts for suspended-bed hydrocracking of heavy oils by doping with Zr atoms
    Yongde Ma, Rengan Liang, Wenquan Wu, Jiayin Zhang, Yanning Cao, Kuan Huang, Lilong Jiang
    2021, 39(11):  126-134.  doi:10.1016/j.cjche.2021.03.015
    Abstract ( 55 )   PDF (7563KB) ( 81 )  
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    Developing catalysts with not only hydrogenation activity but also cracking activity is very important for the advancement of suspended-bed hydrocracking technology. Within this respect, MoS2/SiO2-Al2O3 bifunctional catalyst is a kind of typical catalysts with both hydrogenation and cracking activity. Herein, a series of Zr-doped SiO2-Al2O3 mixed oxides were synthesized by a sol-gel coupled with hydrothermal method. The synthesized mixed oxides were characterized for chemical structures and acidic properties. It is found that doping SiO2-Al2O3 with Zr atoms significantly increases the numbers of acidic sites. The Zr-doped SiO2-Al2O3mixed oxides were then combined with dispersed MoS2, which was in-situ produced from oil-soluble Mo precursors, to fabricate a novel kind of bifunctional catalysts for suspended-bed hydrocracking of heavy oils. Owing to the significantly increased numbers of acidic sites in Zr-doped SiO2-Al2O3 mixed oxides, corresponding bifunctional catalysts demonstrate much enhanced activity for suspended-bed hydrocracking of heavy oils in relative to MoS2/SiO2-Al2O3 bifunctional catalysts.
    The size effect and high activity of nanosized platinum supported catalysts for low temperature oxidation of volatile organic compounds
    Ziqing Yuan, Ziyu Chen, Jianxin Mao, Renxian Zhou
    2021, 39(11):  135-143.  doi:10.1016/j.cjche.2020.09.029
    Abstract ( 34 )   PDF (8478KB) ( 46 )  
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    Pt/Al2O3 catalysts with smaller size of Pt nanoparticles were prepared by ethylene glycol reduction method in two different way and their oxidation activities for three typical VOCs (volatile organic compounds) were evaluated. The catalyst prepared by first adsorption and then reduction procedure is denoted as L-Pt/Al2O3 while the catalyst prepared by first reduction and then loading procedure is defined as R-Pt/Al2O3. The results show that L-Pt/Al2O3 with the stronger interaction between Pt species and Al2O3 exhibit smaller size of Pt nanoparticles and favorable thermal stability compared with R-Pt/Al2O3. L-Pt/Al2O3 is favor of the formation of more adsorbed oxygen species and more Pt2+ species, resulting in high catalytic activity for benzene and ethyl acetate oxidation. However, R-Pt/Al2O3 catalysts with higher proportion of Pt0/Pt2+ and bigger size of Pt particles exhibits higher catalytic activity for n-hexane oxidation. Pt particles in R-Pt/Al2O3 were aggregated much more serious than that in L-Pt/Al2O3 at the same calcination temperature. The Pt particles supported on Al2O3 with~10 nm show the best catalytic activity for n-hexane oxidation.
    Catalytic hydrogenation performance of ZIF-8 carbide for electrochemical reduction of carbon dioxide
    Shuai Fan, Huiyuan Cheng, Manman Feng, Xuemei Wu, Zihao Fan, Dongwei Pan, Gaohong He
    2021, 39(11):  144-153.  doi:10.1016/j.cjche.2021.05.032
    Abstract ( 42 )   PDF (8328KB) ( 16 )  
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    The conversion of CO2 electrocatalytic hydrogenation into energy-rich fuel is considered to be the most effective way to carbon recycle. Nitrogen-doping carbonized ZIF-8 is proposed as carrier of the earth-rich Sn catalyst to overcome the limit of electron transfer and CO2 adsorption capacity of Sn. Hierarchically porous structure of Sn doped carbonized ZIF-8 is controlled by hydrothermal and carbonization conditions, which induces much higher specific surface area than that of the commercial Sn nanoparticle (1003.174 vs. 7.410 m2·g-1). The shift of nitrogen peaks in X-ray Photoelectron Spectroscopy spectra indicates interaction between ZIF-8 and Sn, which induces the shift of electron cloud from Sn to the chemical nitrogen to enhance conductivity and regulate electron transfer from catalyst to CO2. Lower mass transfer resistance and Warburg resistance are investigated through EIS, which significantly improves the catalytic activity for CO2 reduction reaction (CO2RR). Onset potential of the reaction is reduced from -0.74 V to less than -0.54 V vs. RHE. The total Faraday efficiency of HCOOH and CO reaches 68.9% at -1.14 V vs. RHE, which is much higher than that of the commercial Sn (45.0%) and some other Sn-based catalyst reported in the literature.
    Chemical functionalization of chitosan biopolymer and chitosan-magnetite nanocomposite with sulfonic acid for acid-catalyzed reactions
    Majid Masteri-Farahani, Samaneh Shahsavarifar
    2021, 39(11):  154-161.  doi:10.1016/j.cjche.2021.04.037
    Abstract ( 34 )   PDF (5313KB) ( 22 )  
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    Chemical functionalization of chitosan biopolymer and chitosan-magnetite nanocomposite was performed with sulfonic acid functional groups to achieve new solid acid materials. The sulfonic acid functional groups were created through the ring opening nucleophilic reaction of amine groups of chitosan with 1,4-butane sultone. Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopies (XPS) verified the successful sulfonic acid functionalization of chitosan. The obtained sulfonic acid functionalized chitosan-magnetite nanocomposite showed superparamagnetic properties according to the vibrating sample magnetometry analysis and exhibited magnetic separation feature from dispersed mixtures. Nitrogen adsorption-desorption analysis indicated the increase in surface area after formation of chitosan-magnetite nanocomposite and functionalization with sulfonic acid. Both of the prepared solid acids exhibited high catalytic activities in the acid-catalyzed acetic acid esterification with n-butanol and benzaldehyde acetalization with ethylene glycol as model reactions. Furthermore, they can be reused several times without considerable loss of their activities.
    An efficient method for enhancing adhesion and uniformity of Al2O3 coatings on nickel micro-foam used in micropacked beds
    Chi Ma, Le Sang, Xiaonan Duan, Jiabin Yin, Jisong Zhang
    2021, 39(11):  162-172.  doi:10.1016/j.cjche.2021.05.022
    Abstract ( 46 )   PDF (11229KB) ( 115 )  
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    Methods of coating Al2O3 on nickel micro-foam were compared and screened, aiming to overcome the capillary force and prepare the micro-foam monolithic catalyst coatings. The surface of micro-foam substrate was pretreated by a chemical etching method to improve the adhesion of the coatings on the substrate. The results showed that the slurry circulation at 162 ml·min-1 was evaluated as the optimal method. The pore size on the substrate surface can be controlled by changing the pretreatment conditions. An empirical correlation was also proposed, showing an excellent practicality for predicting the pore size. The adhesion of the coatings with substrate pretreatment was significantly better than that without substrate pretreatment. The minimum value of mass loss after ultrasonic vibration was 3.9%. This mainly attributes to the squeezing of Al2O3 particles in the pores of substrate surface. The coatings on nickel micro-foam are hopefully used in micropacked beds for catalytic reactions.
    Thermodynamics and kinetics insights into naphthalene hydrogenation over a Ni-Mo catalyst
    Chong Peng, Zhiming Zhou, Xiangchen Fang, Hualin Wang
    2021, 39(11):  173-182.  doi:10.1016/j.cjche.2021.02.007
    Abstract ( 57 )   PDF (4565KB) ( 47 )  
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    Hydrocracking represents an important process in modern petroleum refining industry, whose performance mainly relies on the identity of catalyst. In this work, we perform a combined thermodynamics and kinetics study on the hydrogenation of naphthalene over a commercialized NiMo/HY catalyst. The reaction network is constructed for the respective production of decalin and methylindane via the intermediate product of tetralin, which could further undergo hydrogenation to butylbenzene, ethylbenzene, xylene, toluene, benzene, methylcyclohexane and cyclohexane. The thermodynamics analysis suggests the optimum operating conditions for the production of monoaromatics are 400℃, 8.0 MPa, and 4.0 hydrogen/naphthalene ratio. Based on these, the influences of reaction temperature, pressure, hydrogen/naphthalene ratio, and liquid hourly space velocity (LHSV) are investigated to fit the Langmuir-Hinshelwood model. It is found that the higher temperature and pressure while lower LHSV favors monoaromatics production, which is insensitive to the hydrogen/naphthalene ratio. Furthermore, the high consistence between the experimental and simulated data further validates the as-obtained kinetics model on the prediction of catalytic performance over this kind of catalyst.
    Process Systems Engineering and Process Safety
    Quality oriented multimode processes monitoring based on a novel hierarchical common and specific structure with different order information
    Yun Wang, Yuchen He, De Gu
    2021, 39(11):  183-192.  doi:10.1016/j.cjche.2020.09.067
    Abstract ( 44 )   PDF (6297KB) ( 23 )  
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    Due to higher demands on product diversity, flexible shift between productions of different products in one equipment becomes a popular solution, resulting in existence of multiple operation modes in a single process. In order to handle such multi-mode process, a novel double-layer structure is proposed and the original data are decomposed into common and specific characteristics according to the relationship between variables among each mode. In addition, both low and high order information are considered in each layer. The common and specific information within each mode can be captured and separated into several subspaces according to the different order information. The performance of the proposed method is further validated through a numerical example and the Tennessee Eastman (TE) benchmark. Compared with previous methods, superiority of the proposed method is validated by the better monitoring results.
    Distributed model predictive control based on adaptive sampling mechanism
    Zhen Wang, Aimin An, Qianrong Li
    2021, 39(11):  193-204.  doi:10.1016/j.cjche.2020.10.048
    Abstract ( 41 )   PDF (11434KB) ( 14 )  
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    In this work, an adaptive sampling control strategy for distributed predictive control is proposed. According to the proposed method, the sampling rate of each subsystem of the accused object is determined based on the periodic detection of its dynamic behavior and calculations made using a correlation function. Then, the optimal sampling interval within the period is obtained and sent to the corresponding sub-prediction controller, and the sampling interval of the controller is changed accordingly before the next sampling period begins.In the nextcontrolperiod, the adaptive sampling mechanism recalculates the sampling rate of each subsystem's measurable output variable according to both the abovementioned method and the change in the dynamic behavior of the entire system, and this process is repeated. Such an adaptive sampling interval selection based on an autocorrelation function that measures dynamic behavior can dynamically optimize the selection of sampling rate according to the real-time change in the dynamic behavior of the controlled object. It can also accurately capture dynamic changes, meaning that each sub-prediction controller can more accurately calculate the optimal control quantity at the next moment, significantly improving the performance of distributed model predictive control (DMPC). A comparison demonstrates that the proposed adaptive sampling DMPC algorithm has better tracking performance than the traditional DMPC algorithm.
    Biotechnology and Bioengineering
    Quantitative evaluation of DNA damage caused by atmospheric and room-temperature plasma (ARTP) and other mutagenesis methods using a rapid umu-microplate test protocol for microbial mutation breeding
    Yuting Huang, Liyang Wang, Xue Zhang, Nan Su, Heping Li, Yoshimitsu Oda, Xinhui Xing
    2021, 39(11):  205-210.  doi:10.1016/j.cjche.2021.01.009
    Abstract ( 56 )   PDF (2195KB) ( 58 )  
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    Mutagenesis is an important technique for microbial mutation breeding. As the source of mutations, DNA damage extent is a key indicator for the effectiveness of mutagenesis. Therefore, a rapid and easy DNA damage quantification method is required for the comparison of mutagenesis effects and development of mutagenesis tools. Here, we used the umu-microplate test system to quantitatively compare the DNA damage strength caused by atmospheric and room-temperature plasma (ARTP) and other traditional mutagenesis methods including:ultraviolet radiation (UV), diethyl sulfate (DES) and 4-nitroquinoline-1-oxide (4-NQO). The test strain of Salmonella typhimurium TA1535/pSK1002 was used to monitor the time-course profile of β-galactosidase activity induced by DNA damage caused by different mutagenesis methods using a microplate reader. The umu-microplate test results showed that ARTP caused higher extent of DNA damage than UV and chemical mutagens, which agrees well with the result obtained by SOS-FACS-based quantification method as reported previously. This umu-microplate test is accessible for broad researchers who are lack of the expensive FACS instruments and allows the quick quantitative evaluation of DNA damage among living cells for different mutagenesis methods in the study of the microbial mutation breeding.
    Production and characterization of insoluble α-1,3-linked glucan and soluble α-1,6-linked dextran from Leuconostoc pseudomesenteroides G29
    Yiya Wang, Tao Sun, Yinzhu Wang, Hao Wu, Yan Fang, Jiangfeng Ma, Min Jiang
    2021, 39(11):  211-218.  doi:10.1016/j.cjche.2021.06.020
    Abstract ( 38 )   PDF (1200KB) ( 17 )  
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    Exopolysaccharides can be produced by various bacteria and have important biological roles in bacterial survival depend on molecular weight, linkage, and conformation. In this study, Leuconostoc pseudomesenteroides G29 was identified and found to produce two types of exopolysaccharides from sucrose including soluble and insoluble α-glucans. By regulation of pH above 5.5, soluble α-glucan production was increased to 38.4 g·L-1 from 101.4 g·L-1 sucrose with fewer accumulation of lactic acid and acetic acid. Simultaneously, the quantity of thick white precipitate, that is insoluble α-glucan, was also increased. Then, α-glucans were prepared by enzymatic reaction with crude glucansucrases from the supernatant of G29 fermentation broth and purified for structure analysis. Based on the integration analysis of FT-IR and NMR, it was observed that soluble α-glucan is a highly linear dextran with α-1,6 glycosidic bonds while the insoluble α-glucan has 93% of α-1,3 and 7% of α-1,6 glycosidic bond. The results extend our understanding of exopolysaccharides production by L. pseudomesenteroides, and this water insoluble α-1,3-glucan might have potential application as biomaterials and/or biochemicals.
    Intelligent self-assembly prodrug micelles loading doxorubicin in response to tumor microenvironment for targeted tumors therapy
    Dong Wan, Sunfan Li, Jianxin Zhang, Guilei Ma, Jie Pan
    2021, 39(11):  219-227.  doi:10.1016/j.cjche.2021.06.023
    Abstract ( 50 )   PDF (7433KB) ( 14 )  
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    Compared with physical drug-loaded nanocarriers, polymeric prodrug micelles have many advantages such as high drug loading and enhanced stability in blood, so they have great potential in cancer therapy. However, these micelles have a big disadvantage, which cannot achieve long-term circulation in vivo and high absorption of tumor cells simultaneously, resulting in low administration efficiency and poor therapeutic effect on cancer. To solve problems of traditional polymeric prodrug micelles, novel polymeric micelles with tumor microenvironment response were designed in this work. The prodrug formed by covalently linking D-α-tocopherol polyethylene glycol succinate (TPGS3350), peptide (Pep), and doxorubicin (DOX) (TPGS3350-Pep-DOX) was self-assembled into micelles by encapsulating DOX physically. When the micelles entered the tumor tissue, the long-chain polyethylene glycol (PEG) was sensitively cut by the matrix metalloproteinase 2/9 (MMP2/9) enzyme, exposing the targeting molecule folate, then it entered the cell through the endocytic pathway mediated by the folate receptor. The drug loading content, encapsulation efficiency, critical micelle concentration, and invitro release of the micelles invented in this study were measured to characterize their properties. The particle size and zeta potential of micelles were characterized by dynamic light scattering. Images were scanned by transmission electron microscopes. In vitro cytotoxicity, cellular uptake, and in vivo antitumor effect evaluation experiments were measured to show that smart micelles have made much progress in material chemistry and drug delivery, making it possible to apply a stimulus-response carrier drug delivery system in clinical application.
    Anaerobic-aerobic processes for the treatment of textile dyeing wastewater containing three commercial reactive azo dyes: Effect of number of stages and bioreactor type
    Banafsheh Azimi, Elham Abdollahzadeh-Sharghi, Babak Bonakdarpour
    2021, 39(11):  228-239.  doi:10.1016/j.cjche.2020.10.006
    Abstract ( 38 )   PDF (6024KB) ( 39 )  
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    In this study, the effect of number of stages and bioreactor type on the removal performance of a sequential anaerobic-aerobic process employing activated sludge for the treatment of a simulated textile dyeing wastewater containing three commercial reactive azo dyes was considered. Two stage processes performed better than one stage ones, both in terms of overall organic and color removal, as well as the higher contribution of anaerobic stage to the overall removal performance, thereby making them a more energy efficient option. The employment of a moving bed sequencing batch biofilm reactor, which uses both suspended and attached biomass, for the implementation of the anaerobic stage of the process, was compared with a sequencing batch reactor that only employs suspended biomass. The results showed that, although there was no meaningful difference in biomass concentration between the two bioreactors, the latter reactor had better performance in terms of chemical oxygen demand (COD) removal efficiency and rate and color removal rate. Further exploratory tests revealed a difference between the roles of suspended and attached bacterial populations, with the former yielding better color removal whilst the latter had better COD removal performance. The sequential anaerobic-aerobic process, employing an aerobic membrane bioreactor in the aerobic stage resulted in COD and color removal of 77.1±7.9% and 79.9±1.5%, respectively. The incomplete COD and color removal was attributed to the presence of soluble microbial products in the effluent and the autoxidation of dye reduction metabolites, respectively. Also, aerobic partial mineralization of the dye reduction metabolites, was experimentally observed.
    Self-assembled MoS2/C nanoflowers with expanded interlayer spacing as a high-performance anode for sodium ion batteries
    Yuxiang Luo, Pei Zhang, Xunhui Xiong, Haikuo Fu
    2021, 39(11):  240-246.  doi:10.1016/j.cjche.2021.04.013
    Abstract ( 52 )   PDF (8201KB) ( 16 )  
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    Two-dimensional (2D) MoS2 nanomaterials have been extensively studied due to their special structure and high theoretical capacity, but it is still a huge challenge to improve its cycle stability and achieve superior fast charge and discharge performance. Herein, a facile one-step hydrothermal method is proposed to synthetize an ordered and self-assembled MoS2 nanoflower (MoS2/C NF) with expanded interlayer spacing via embedding a carbon layer into the interlayer. The carbon layer in the MoS2 interlayer can speed the transfer of electrons, while the nanoflower structure promotes the ions transport and improves the structural stability during the charging/discharging process. Therefore, MoS2/C NF electrode exhibits exceptional rate performance (318.2 and 302.3 mA·h·g-1 at 5.0 and 10.0 A·g-1, respectively) and extraordinary cycle durability (98.8% retention after 300 cycles at a current density of 1.0 A·g-1). This work provides a simple and feasible method for constructing high-performance anode composites for sodium ion batteries with excellent cycle durability and fast charge/discharge ability.
    Facile synthesis of spinel LiNi0.5Mn1.5O4 as 5.0 V-class high-voltage cathode materials for Li-ion batteries
    Xueyi Guo, Chenlin Yang, Jinxiu Chen, Qinghua Tian, Hongmei Zhang, Guoyong Huang
    2021, 39(11):  247-254.  doi:10.1016/j.cjche.2021.08.001
    Abstract ( 52 )   PDF (5673KB) ( 36 )  
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    LiNi0.5Mn1.5O4 and LiMn2O4 with novel spinel morphology were synthesized by a hydrothermal and post-calcination process. The synthesized LiMn2O4 particles (5-10 μm) are uniform hexahedron, while the LiNi0.5Mn1.5O4 has spindle-like morphology with the long axis 10-15 μm, short axis 5-8 μm. Both LiMn2O4 and LiNi0.5Mn1.5O4 show high capacity when used as cathode materials for Li-ion batteries. In the voltage range of 2.5-5.5 V at room temperature, the LiNi0.5Mn1.5O4 has a high discharge capacity of 135.04 mA·h·g-1 at 20 mA·g-1, which is close to 147 mA·h·g-1 (theoretical capacity of LiNi0.5Mn1.5O4). The discharge capacity of LiMn2O4 is 131.08 mA·h·g-1 at 20 mA·g-1. Moreover, the LiNi0.5Mn1.5O4 shows a higher capacity retention (76%) compared to that of LiMn2O4 (61%) after 50 cycles. The morphology and structure of LiMn2O4 and LiNi0.5Mn1.5O4 are well kept even after cycling as demonstrated by SEM and XRD on cycled LiMn2O4 and LiNi0.5Mn1.5O4 electrodes.
    Lower temperature hydrothermal pretreatment improves the anaerobic digestion performance of spent cow bedding
    Xitong Wang, Hairong Yuan, Xiaocong Song, Xiujin Li, Xiaoyu Zuo
    2021, 39(11):  255-260.  doi:10.1016/j.cjche.2020.10.012
    Abstract ( 49 )   PDF (3913KB) ( 35 )  
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    The anaerobic digestion (AD) performance of spent cow bedding was investigated with different hydrothermal pretreatment (HP) conditions. Spent cow bedding was pretreated with low temperatures (50, 70, and 90℃) and different pretreatment times (2-72 h) with ammonia and without ammonia. The results showed that spent cow bedding was a good raw material for AD. After pretreatment, the concentration of volatile fatty acids (VFAs) in the group of hydrothermal pretreatments with ammonia (HPA) was higher than that in the HP group at the same pretreatment temperature and time. The optimal pretreatment condition was achieved with an HPA of 50℃ holding for 72 h. At the optimal condition, the highest concentration of VFAs was 1.58-10.85 times higher than that of the other pretreated groups. The highest hemicellulose and lignin removal rates were 58.07% and 10.32%, respectively. The highest methane yield was 163.0 ml·(g VS)-1, which was 48.9% higher than that of the untreated group. The VFAs, pH, and reducing sugars showed positive relationships with the methane yield. Therefore, HP at low temperature can enhance the AD performance of spent cow bedding.
    Pre-sodiation strategy for superior sodium storage batteries
    Yongkai Xu, Haozheng Sun, Cunshuang Ma, Jingjing Gai, Yanhua Wan, Weihua Chen
    2021, 39(11):  261-268.  doi:10.1016/j.cjche.2021.08.020
    Abstract ( 65 )   PDF (10578KB) ( 81 )  
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    The irreversible consumption of sodium in the initial several cycles greatly led to the attenuation of capacity, which caused the low initial coulombic efficiency (ICE) and obvious poor cycle stability. Pre-sodiation can effectively improve the electrochemical performance by compensating the capacity loss in the initial cycle. Here, carbon-coated sodium-pretreated iron disulfide (NaFeS2@C) has been synthesized through conventional chemical method and used in sodium metal battery as a cathode material. The calculated density of states (DOS) of NaFeS2@C is higher, which implies enhanced electron mobility and improved cycle reversibility. Because of the highly reversible conversion reaction and the compensation of irreversible capacity loss during the initial cycle, the Na/NaFeS2@C battery achieves ultra-high initial coulombic efficiency (96.7%) and remarkable capacity (751 mA·h·g-1 at 0.1 A·g-1). In addition, highly reversible electrochemical reactions and ultra-thin NaF-rich solid electrolyte interphase (SEI) also benefit for the electrochemical performance, even at high current density of 100 A·g-1, it still exhibits a reversible capacity of 136 mA·h·g-1, and 343 mA·h·g-1 after 2500 cycles at 5.0 A·g-1. This work aims to bring up new insights to improve the ICE and stability of sodium metal batteries.
    Barium-doped Pr2Ni0.6Cu0.4O4+δ with triple conducting characteristics as cathode for intermediate temperature proton conducting solid oxide fuel cell
    Chengyi Ai, Tingting Li, Rongzheng Ren, Zhenhua Wang, Wang Sun, Jinsheng Feng, Kening Sun, Jinshuo Qiao
    2021, 39(11):  269-276.  doi:10.1016/j.cjche.2021.09.010
    Abstract ( 41 )   PDF (6276KB) ( 38 )  
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    Proton conducting solid oxide fuel cell (H-SOFC) is an emerging energy conversion device, with lower activation energy and higher energy utilization efficiency. However, the deficiency of highly active cathode materials still remains a major challenge for the development of H-SOFC. Therefore, in this work, K2NiF4-type cathode materials Pr2-xBaNi0.6Cu0.4O4+δ (x=0, 0.1, 0.2, 0.3), single-phase triple-conducting (e-/O2-/H+) oxides, are prepared for intermediate temperature H-SOFCs and exhibit good oxygen reduction reaction activity. The investigation demonstrates that doping Ba into Pr2-xBaNi0.6Cu0.4O4+δ can increase its electrochemical performance through enhancing electrical conductivity, oxygen vacancy concentration and proton conductivity. EIS tests are carried at 750℃ and the minimum polarization impedances are obtained when x=0.2, which are 0.068 Ω·cm2 in air and 1.336 Ω·cm2 in wet argon, respectively. The peak power density of the cell with Pr1.8Ba0.2Ni0.6Cu0.4O4+δ cathode is 298 mW·cm-2 at 750℃ in air with humidified hydrogen as fuel. Based on the above results, Ba-doped Pr2-xBaNi0.6Cu0.4O4+δ can be a good candidate material for SOFC cathode applications.
    Effective enhancement of the electrochemical properties for Na2FeP2O7/C cathode materials by boron doping
    He Zhao, Jianzhong Li, Haoyuan Xu, Xuanwen Gao, Junjie Shi, Kai Yu, Xueyong Ding
    2021, 39(11):  277-285.  doi:10.1016/j.cjche.2021.09.011
    Abstract ( 37 )   PDF (10413KB) ( 38 )  
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    In recent years, the composite materials based on polyanionic frameworks as secondary sodium ion battery electrode material have been developed in large-scale energy storage applications due to its safety and stability. The Na2FeP2O7/C (theoretical capacity 97 mA·h·g-1) is recognized as optimum Na-storage cathode materials with a trade-off between electrode performance and cost. In the present work, The Na2FeP2O7/C and boron-doped Na2FeP2-BO7/C composites were synthesized via a novel method of liquid phase combined with high temperature solid phase. The non-metallic element B doping not only had positive influence on the crystal structure stability, Na+ diffusion and electrical conductivity of Na2FeP2O7/C, but also contributed to the high-value recycling of B element in waste borax. The structure and electrochemical properties of the cathode material were investigated via X-ray diffraction (XRD), scanning electron microscopy (SEM), The X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and charge/discharge cycling. The results showed that different amounts of boron doping had positive effects on the structure and electrochemical properties of the material. The initial charge/discharge performances of born doped materials were improved in comparison to the bare Na2FeP2O7/C. The cycle performance of the Na2FeP1.95B0.05O7/C showed an initial reversible capacity of 74.8 mA·h·g-1 and the high capacity retention of 91.8% after 100 cycles at 1.0 C, while the initial reversible capacity of the bare Na2FeP2O7/C was only 66.2 mA·h·g-1. The improvement of apparent Na+ diffusion and electrical conductivity due to B doping were verified by the EIS test and CVs at various scan rate. The experimental results from present work is useful for opening new insight into the contrivance and creation of applicable sodium polyanionic cathode materials for high-performance.
    Prediction of methane storage in covalent organic frameworks using big-data-mining approach
    Huan Zhang, Peisong Yang, Duli Yu, Kunfeng Wang, Qingyuan Yang
    2021, 39(11):  286-296.  doi:10.1016/j.cjche.2021.03.002
    Abstract ( 47 )   PDF (8614KB) ( 15 )  
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    A combination of computational materials screening and machine learning (ML) technique is being adopted as a popular approach to study various materials toward application of interest. In this work, we began with high-throughput molecular simulations to calculate the methane storage (6.5 MPa) and deliverable (6.5-0.58 MPa) capacities of 404,460 covalent organic frameworks (COFs) at 298 K. Then, the full data sets with 23 features were randomly split into training and test sets in a ratio of 20:80, which were applied to evaluate the prediction abilities of several ML algorithms, including gradient boosting decision tree (GBDT), neural network (NN), support vector machine (SVM), random forest (RF) and decision tree (DT). The results indicate that the RF model has the highest prediction accuracy, which was further employed to reduce the dimension of features space and quantitatively analyze the relative importance of each feature value. The binary classification predictors built using the features with the highest influence weight can give a successful identification of top-performing candidates from the test set containing 323,168 COFs with an accuracy exceeding 96%. The deliverable capacities of the identified COFs were found to outperform those reported so far for various adsorbents. The findings may provide a useful guidance for the design and synthesis of new high-performance materials for methane storage application.
    Construction and evaluation of co-electrospun poly (butylene succinate)/gelatin materials as potential vascular grafts
    Tingting Yang, Han Xu, Congrui Zhao, Di Tang, Fan Mu, Hongjiang Lu, Zhoufeng Rao, Shufang Wang
    2021, 39(11):  297-305.  doi:10.1016/j.cjche.2021.06.015
    Abstract ( 42 )   PDF (10501KB) ( 13 )  
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    In this study, a series of poly (butylene succinate) (PBSU)/gelatin composites were prepared by electrospinning. The morphology, physicochemical analysis, biomechanical properties, biocompatibility, and biodegradability of the materials were evaluated. The results showed that the ultimate tensile stress of the vascular PBSU/gelatin grafts at (95/5), (90/10), (85/15), and (80/20) was (4.17±0.54) MPa, (3.81±0.44) MPa, 2.94±0.69 MPa and 2.11±0.72 MPa respectively, and the burst pressure was (282.7±22.3) kPa, (295.3±3.9) kPa, (306.8±13.9) kPa and (307.6±9.0) kPa respectively, which met the requirements of tissue-engineered blood vessels. Furthermore, the addition of gelatin improved the hydrophilicity and degradation properties of PBSU, thus enhancing cell adhesion and promoting the inward growth of vascular smooth muscle cells. In summary, the research in this paper provides a useful reference for the preparation and optimization of vascular scaffolds.
    Alkylation of naphthalene with n-butene catalyzed by liquid coordination complexes and its lubricating properties
    Chen Chen, Qiong Tang, Hong Xu, Lei Liu, Mingxing Tang, Xuekuan Li, Jinxiang Dong
    2021, 39(11):  306-313.  doi:10.1016/j.cjche.2021.01.014
    Abstract ( 43 )   PDF (4735KB) ( 156 )  
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    With the development of coal chemical industry, large amounts of naphthalene and n-butene are produced, and converting them into high value-added products through alkylation has gained particular importance and interest. In this work, liquid coordination complexes (LCCs) were used as acid catalysts for the first time in the naphthalene alkylation reaction under mild conditions to obtain multi-butylnaphthalenes with high yield. Various reaction conditions were thoroughly investigated. The LCC consisting of urea and AlCl3 showed excellent catalytic performance under optimal reaction conditions, giving 100% conversion of naphthalene and 99.66% selectivity towards multi-butylnaphthalenes. Combining the catalyst properties and catalytic results, a plausible reaction mechanism was proposed. The lubricating properties of the synthesized products were investigated for their potential application as lubricating base oils. The synthesized multi-butylnaphthalenes showed comparable physicochemical properties and tribological performances as the commercial cycloalkyl base oil.
    Influence of anode current density on carbon parasitic reactions during electrolysis
    Tongxiang Ma, Lang Zhao, Yu Yang, Liwen Hu, Shengfu Zhang, Meilong Hu
    2021, 39(11):  314-319.  doi:10.1016/j.cjche.2021.05.011
    Abstract ( 36 )   PDF (5944KB) ( 29 )  
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    In the electro-deoxidation process, carbon parasitic reaction (CO32- + 4e-=C + 3O2-) usually occurs when using carbon materials as the anode, which leads to increase of the carbon content in the final metal and decrease of the current efficiency of the process. The aim of this work is to reduce the negative effect of carbon parasitic reaction on the electrolysis process by adjusting anode current density. The results indicate that lower graphite anode area can achieve higher current density, which is helpful to increase the nucleation site of CO2 bubbles. Most of CO2 would be released from the anode instead of dissolution in the molten CaCl2 and reacting with O2- to form CO32-, thus decreasing the carbon parasitic reaction of the process. Furthermore, the results of the compared experiments show that when the anode area decreases from 172.78 to 4.99 cm2, CO2 concentration in the released gases increases significantly, the carbon mass content in the final metal product decreased from 1.09% to 0.13%, and the current efficiency increased from 6.65% to 36.50%. This study determined a suitable anode current density range for reducing carbon parasitic reaction and provides a valuable reference for the selection of the anode in the electrolysis process.