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SCI和EI收录∣中国化工学会会刊
本期目录
2022年 第45卷 第5期 刊出日期:2022-05-28
    Conjugated microporous polymer membranes for chemical separations
    Zongyao Zhou, Zhen Li, Lubna M. Rehman, Zhiping Lai
    中国化学工程学报. 2022, 45(5):  1-14.  doi:10.1016/j.cjche.2022.01.027
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    Conjugated microporous polymers (CMPs) are a unique class of porous organic materials, which are constructed with π-conjugation structures leading to intrinsic micropores. The CMPs properties such as high surface area, intrinsic and rich micropores, interlocking and rigid structure, extensive π-conjugation and tunable band-gap, chemical and thermal stability, together with tailored functionalities, contribute to its abundant potential for application in fields such as photocatalysis, optoelectronics, energy storage, and chemical sensors. Recently, CMPs have gained importance in the field of membranes for chemical separation. In this review, we briefly discuss the historical development of CMPs, followed by a detailed description of the progress in state-of-the-art design, preparation, and application of CMPs in membranes. Additionally, we provide inference on the future prospects of CMPs as membranes.
    Atomic layer deposition of TiO2 on carbon-nanotubes membrane for capacitive deionization removal of chromium from water
    Jianhua Feng, Sen Xiong, Li Ren, Yong Wang
    中国化学工程学报. 2022, 45(5):  15-21.  doi:10.1016/j.cjche.2021.05.014
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    Chromium (Cr) is a common heavy metal that has severe impacts on the ecosystem and human health. Capacitive deionization (CDI) is an environment-friendly and energy-efficient electrochemical purification technology to remove Cr from polluted water. The performance of CDI systems relies primarily on the properties of electrodes. Carbon-nanotubes (CNTs) membranes are promising candidates in creating advanced CDI electrodes and processes. However, the low electrosorption capacity and high hydrophobicity of CNTs greatly impede their applications in water systems. In this study, we employ atomic layer deposition (ALD) to deposit TiO2 nanoparticulates on CNTs membranes for preparing electrodes with hydrophilicity. The TiO2-deposited CNTs membranes display preferable electrosorption performance and reusability in CDI processes after only 20 ALD cycles deposition. The total Cr and Cr(VI) removal efficiencies are significantly improved to 92.1% and 93.3%, respectively. This work demonstrates that ALD is a highly controllable and simple method to produce advanced CDI electrodes, and broadens the application of metal oxide/carbon composites in the electrochemical processes.
    Application of pulsed chemical vapor deposition on the SiO2-coated TiO2 production within a rotary reactor at room temperature
    Ke Yang, Shan Zhong, Hairong Yue, Siyang Tang, Kui Ma, Changjun Liu, Kai Qiao, Bin Liang
    中国化学工程学报. 2022, 45(5):  22-31.  doi:10.1016/j.cjche.2021.05.012
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    Pulsed chemical vapor deposition (P-CVD) is a promising technology for the surface modification of TiO2 particles. For the scale-up application of P-CVD, a custom-designed rotary reactor and corresponding coating process at room temperature was developed in the present work. The obtained SiO2-coated TiO2 particles were characterized by various measures including high-resolution transmission electron microscope, Fourier transform infrared spectroscopy, X-ray diffraction, etc. The results illustrated that the SiO2 films with a thickness of (3.7 ±0.7) nm were successfully deposited onto the surface of TiO2 particles. According to the dye degradation tests and acid solubility measurement, the deposited film can effectively inhibit the photocatalytic activity and enhance the weatherability of the TiO2 particles. Zeta potential measurements showed that the SiO2-coated TiO2 is possible to be stably dispersed in the pH range of 6.9–11.6. The coating process made the whiteness of TiO2 particles decreased slightly but still sufficient (97.3 ±0.1) for application. Furthermore, the properties of the TiO2 particles coated by P-CVD were compared with the particles coated by traditional wet chemical deposition. It is shown that the P-CVD can produce thinner but denser films with better photoactivity suppression performance. The developed coating process within the rotary reactor was proved practically feasible and convenient for the scale-up production of SiO2-coated TiO2 via P-CVD.
    Process monitoring of the Au-S bond conversion in acetylene hydrochlorination
    Lutai Song, Li Liu, Mingyuan Zhu, Bin Dai
    中国化学工程学报. 2022, 45(5):  32-40.  doi:10.1016/j.cjche.2021.04.026
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    The continuous expansion of vinyl chloride production increases environmental pollution caused by mercury catalysts, which is an issue that urgently needs to be solved. Green and stable catalysts should be researched to alleviate this issue. In this research, Thiolactic acid acts as a ligand where sulfhydryl groups form a stable complex with Au on the surface of a spherical activated carbon (SAC). An Au-thiolactic acid/SAC catalyst was designed with a Au theoretical loading of 0.5% (mass) to overcome the disadvantages of traditional Au-based catalysts, such as a low conversion rate and poor life cycle. The ratio of Au to ligand was screened, and the activity was best when Au/S = 1:8. The formation of the Au-S bond was proven by FT-IR and UV–vis. The longevity test of the Au1S8 /SAC catalyst was carried out at 1200 h-1 for 50 h. Samples with reaction times of 0 h, 5 h, 10 h, 20 h, and 50 h were taken to monitor the catalyst status. The XPS and TPR tests proved that the Au-S bond broke as the acetylene hydrochlorination reaction proceeded. The DFT calculation proved that the Au-S bond is the active site, and the sulfur atom promotes the adsorption of C2H2 by the catalyst.
    Tuning the properties of Ni-based catalyst via La incorporation for efficient hydrogenation of petroleum resin
    Qunhong Liu, Jiangtao Yang, Hongwei Zhang, Hongming Sun, Shuzheng Wu, Bingqing Ge, Rong Wang, Pei Yuan
    中国化学工程学报. 2022, 45(5):  41-50.  doi:10.1016/j.cjche.2021.03.053
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    The hydrogenation of petroleum resin (PR) is an effective process to prepare high value-added hydrogenated PR (HPR). However, the preparation of non-noble metal-based catalysts with high catalytic activity for PR hydrogenation still remains a challenge. Herein, a La promoted Ni-based catalyst is reported through the thermal reduction of quaternary NiLaMgAl-layered double hydroxides (NiLaMgAl-LDHs). The incorporation of La is beneficial to the reduction and stability of Ni particles with reduced particle size, and the increased alkalinity effectively mitigates the breakage of molecular chains of PR. As a result, the La promoted Ni-based catalyst exhibits high catalytic activity and excellent stability for PR hydrogenation. A hydrogenation degree of 95.4% and 96.1% can be achieved for HC5PR and HC9PR with less reduced softening point, respectively. Notably, the hydrogenation degree still maintains at 92.7% even after 100 hours’ reaction, much better than that without La incorporation or prepared using conventional impregnation method.
    An asymmetrically substituted dithieno[3,2-b:2',3'-d]pyrrole organic small-molecule hole-transporting material for high-performance perovskite solar cells
    Jingwen Jia, Yue Zhang, Liangsheng Duan, Quanping Wu, Yu Chen, Song Xue
    中国化学工程学报. 2022, 45(5):  51-57.  doi:10.1016/j.cjche.2021.03.052
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    Hole-transporting materials play a vital role in terms of the performance of perovskite solar cells (PSCs). The dithieno[3,2-b:2',3'-d]pyrrole (DTP), an S,N-heterocyclic building block, has been proved to be desirable for molecular design of hole-transporting materials in PSCs. We developed an asymmetrically substituted DTP small-molecule (JW12) and a reference compound (JW11). The asymmetrical structure of JW12 leads to different absorption properties and electron distribution. The device in a planar n-i-p architecture using JW12 shows a much higher PCE (18.07%) than that based on JW11 (15.46%), which is also better than the device based on spiro-OMeTAD (17.47%). We hope our research can provide a new perspective in molecular design of organic HTMs for perovskite solar cells.
    Synthesis and mechanism analysis of a new oil soluble viscosity reducer for flow improvement of Chenping heavy oil
    Yaqi Ren, Shuqian Xia
    中国化学工程学报. 2022, 45(5):  58-67.  doi:10.1016/j.cjche.2021.04.029
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    Oil soluble viscosity reducers have gradually attracted the attention of petrochemical research due to their cleanliness and high efficiency. Considering the high viscosity and non-Newtonian fluid properties of Chenping heavy oil found in China, a series of new oil soluble viscosity reducers with different proportions and molecular weights were prepared by free radical polymerization using octadecyl acrylate, 2-allylphenol and N-methylolacrylamide as monomers. The viscosity reducer was applied to different types of heavy oil and found that it exhibited a better effect on heavy oils with high asphaltene content. The test of rheological behavior of heavy oil with additive was performed at wide range of shear rate (3–90 s-1) and temperature range (30–100 ℃). The apparent viscosity reduction rate was up to 70.09%, which was better than the industrially relevant ethylene–vinyl acetate copolymer under the same test condition. In addition, the effect of viscosity reducers on the components of heavy oil and the energy change of the system simulated by molecular dynamics simultaneously was investigated. The consistency of the simulated and experimental results show that the effect of viscosity reduction closely related to the crystallization process of wax and the viscosity reducer can reconstruct the surface structure of asphaltene and diminish the connection of benzene ring.
    A comparative study of the thermal and hydrothermal aging effect on Cu-SSZ-13 for the selective catalytic reduction of NOx with NH3
    Huawang Zhao, Xiaomin Wu, Zhiwei Huang, Ziyi Chen, Guohua Jing
    中国化学工程学报. 2022, 45(5):  68-77.  doi:10.1016/j.cjche.2021.04.039
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    In this work, the characterizations of Cu-SSZ-13 after hydrothermal aging (HTA) and thermal aging (TA) at different temperatures (750, 800, and 850 ℃) are compared, and the differences between those two serious aged samples are analyzed. With this data, the effect of steam on catalysts deactivation during hydrothermal aging is analyzed. The TA at 750 and 800 ℃ causes the dealumination and the agglomeration of Cu2+ ions to CuO, resulting in the activity loss of Cu-SSZ-13. The presence of steam upon HTA at 750 and 800 ℃ aggravates the catalyst deactivation by increasing the Al detachment and the Cu2+ agglomeration. The structure and cupric state are almost the same in the Cu-SSZ-13 after TA and HTA at 850 ℃, respectively, indicating that the steam has little influence on the deactivation. The formation of CuAl2O4 spinel is the primary reason for the deactivation after both HTA and TA at 850 ℃, probably attributed to the strong interaction between Cu2+ ions and framework Al sites at high temperatures.
    Syngas to ethanol on MoCu(2 1 1) surface: Effect of promoter Mo on C—O bond breaking and C—C bond formation
    Lijuan He, Cuimei Zhi, Lixia Ling, Riguang Zhang, Baojun Wang
    中国化学工程学报. 2022, 45(5):  78-89.  doi:10.1016/j.cjche.2021.06.018
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    The mechanism of syngas to ethanol on MoCu(2 1 1) surface has been researched by density functional theory (DFT) calculation, and the effects of Mo as a promoter on C—O bond breaking and C—C bond formation have been discussed. Calculations show that Cu-Mo atoms constitute the active sites on MoCu(2 1 1) surface after Mo atom being served as a promoter of Cu catalyst. Compared with Cu(2 1 1), MoCu(2 1 1) has two improvements. Firstly, CH3 is the most advantageous monomer on the MoCu(2 1 1) surface, which provides abundant CH3 intermediate for syngas to ethanol. Secondly, the C—C bond is formed mainly by inserting CHO into the abundant CH3, and the generated CH3CHO through multiple steps of hydrogenation to generate C2H5OH. The key of the promoter Mo on the MoCu(2 1 1) surface also has been verified by the analysis of its electronic properties. Differential charge density shows that the massive electron transfer from Mo to Cu, projected density of states (pDOS) shows that the electron transfer from Mo to Cu makes the d-band center of MoCu(2 1 1) nearer to the Fermi level, these indicate that the MoCu(2 1 1) catalytic capacity increased. The addition of Mo in the Cu-based catalyst not only can effectively solve the problem of C—O bond breaking, but also promote C—C bond formation. About the influence of Mo content on C—O bond breaking and C—C bond formation, compared with MoCu(2 1 1), the DFT results and the d-band center of Mo2Cu(2 1 1) show that the increase of Mo content could not promote the synergistic effect of Cu/Mo on the generation of ethanol more effectively.
    Experimental and numerical study on improvement performance by wave parallel flow field in a proton exchange membrane fuel cell
    Zijun Li, Shubo Wang, Sai Yao, Xueke Wang, Weiwei Li, Tong Zhu, Xiaofeng Xie
    中国化学工程学报. 2022, 45(5):  90-102.  doi:10.1016/j.cjche.2021.07.016
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    The performance and operation stability of proton exchange membrane fuel cells (PEMFCs) are closely related to the transportation of reactants and water management in the membrane electrode assembly (MEA) and flow field. In this paper, a new three-dimensional wave parallel flow field (WPFF) in cathode was designed and analyzed throughout simulation studies and an experimental method. The experimental results show that the performance of PEMFC with WPFF outperforms that of PEMFC with straight parallel flow field (SPFF). Specifically, the peak power density increased by 13.45% for the PEMFC with WPFF as opposed to PEMFC with SPFF. In addition, the flow field with area of 11.56 cm2 was formed by the assembly of transparent end plate used for cathode and the traditional graphite plate used for anode. To understand the mechanism of the novel flow field improving the performance of PEMFC, a model of PEMFC was proposed based on the geometry, operating conditions and MEA parameters. The thickness of gas diffusion layers (GDL), catalytic layers (CL) and proton exchange membrane were measured by scanning electron microscope. The simulation result shows that compared with SPFF, the WPFF based PEMFC promote the oxygen transfer from flow channel to the surface of CL through GDL, and it was beneficial to remove the liquid water in the flow channel and the MEA.
    Microscopic morphology evolution of the crystal structure of tetrahydrofuran hydrate under flowing condition
    Jialu Zhang, Xiang Liu, Shuai Liu, Yuxing Li, Qihui Hu, Wuchang Wang
    中国化学工程学报. 2022, 45(5):  103-110.  doi:10.1016/j.cjche.2021.07.002
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    The evolution of the hydrate particle structure during growth and agglomeration under flowing condition affects the particle as well as flow characteristic, which plays an important role in the flow assurance as well as heat transfer in refrigeration systems. Therefore, this article conducts experiments to study and observe the growth and agglomeration process in the main forming stage of hydrate. It was found that the growth of tetrahydrofuran hydrate was anisotropic and in a layered growth pattern. Single crystals generally transformed from octahedral structure to octahedral skeleton structure with growth, however some single crystals also deformed into plate type particles. The thickness of the plate type particles increased gradually during growth, and the edge part increased earlier than the middle part. During agglomeration, the hydrate particles contacted and sintered together. Sand as the impurity didn’t serve as the nucleation center but affected the agglomeration of hydrate particles by collisions. In addition, the effect increased as the sand size decreased. Finally, a microstructure model for hydrate growth and agglomeration was proposed, which showed the hydrate structure evolution in these processes and could lay a foundation for studying the flow assurance of hydrate slurry.
    Design and optimization of an integrated process for the purification of propylene oxide and the separation of propylene glycol by-product
    Song Hu, Jinlong Li, Qihua Wang, Weisheng Yang
    中国化学工程学报. 2022, 45(5):  111-120.  doi:10.1016/j.cjche.2021.04.012
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    It is difficult to separate the methanol and hydrocarbons in the propylene oxide (PO) purification process due to their forming azeotrope. As for this, a novel PO separation process, in that the deionized water is employed as extractant and 1,2-propylene glycol (MPG) that is formed from the PO hydrolysis reaction is recovered, is presented in this work. The salient feature of this process is that both the non-catalyzed reactions of PO hydrolysis to form MPG and dipropylene glycol (DPG) are simultaneously considered and MPG by-product with high purity is obtained in virtue of the deionized water as reflux liquid and side take-off in MPG column. In addition, the ionic liquid (IL) extractant is screened through the conductor-like screening model for segment activity coefficient (COSMO-SAC) and the comparisons of separation efficiency between the IL and normal octane (nC8) extractant for the separation of PO and 2-methylpentane are made. With the non-random two-liquid (NRTL) thermodynamic model, the simulation and optimization design for the full flow sheet are performed and the effects of the key operation parameters such as solvent ratio, theoretical stages, feeding stage etc. on separation efficiency are detailedly discussed. The results show that the mass purity and the mass yield of PO can be up to 99.99% and 99.0%, and the condenser duty, reboiler duty and PO loss in the process with IL extractant can be decreased by 69.66%, 30.21% and 78.86% compared to ones with nC8. The total annual cost (TAC) calculation also suggests that the TAC would be significantly reduced if using IL in replace of nC8 for the investigated process. The presented results would provide a useful guide for improving the quality of PO product and the economic efficiency of industrial plant.
    Novel design of lubricant-type vacuum distillation process for lube base oils production from hydrocracking tail oil
    Hui Pan, Xinshuang Li, Yichao Shen, Xiang Wu, Feng Ju, Yuzhe Li, Gaosheng Wu, Bo Ai, Baoyun Xu, Hao Ling
    中国化学工程学报. 2022, 45(5):  121-132.  doi:10.1016/j.cjche.2021.04.035
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    Dividing-wall columns (DWCs) are widely used in the separation of ternary mixtures, but rarely seen in the separation of petroleum fractions. This work develops two novel and energy-efficient designs of lubricant-type vacuum distillation process (LVDP) for the separation of hydroisomerization fractions (HIF) of a hydrocracking tail oil (HTO). First, the HTO hydroisomerization reaction is investigated in an experimental fixed-bed reactor to achieve the optimum liquid HIF by analyzing the impact of the operating conditions. A LVDP used for HIF separation is proposed and optimized. Subsequently, two thermal coupling intensified technologies, including side-stream (SC) and dividing-wall column (DWC), are combined with the LVDP to develop side-stream vacuum distillation process (SC-LVDP) and dividing-wall column vacuum distillation process (DWC-LVDP). The performance of LVDP, SC-LVDP, and DWC-LVDP are evaluated in terms of energy consumption, capital cost, total annual cost, product yields, and stripping steam consumption. The results demonstrates that the intensified processes, SC-LVDP and DWC-LVDP significantly decreases the energy consumption and capital cost compared with LVDP. DWC-LVDP further decreases in capital cost due to the removal of the side stripper and narrows the overlap between the third lube oils and fourth lube oils. This study attempts to combine DWC structure into the separation of petroleum fractions, and the proposed approach and the results presented provide an incentive for the industrial implementation of high-quality utilization of HTO through intensified LVDP.
    Catalytic decomposition and mass transfer of aqueous ozone promoted by Fe-Mn-Cu/γ-Al2O3 in a rotating packed bed
    Weizhou Jiao, Xingyue Wei, Shengjuan Shao, Youzhi Liu
    中国化学工程学报. 2022, 45(5):  133-142.  doi:10.1016/j.cjche.2021.03.050
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    This study investigated catalytic decomposition and mass transfer of aqueous ozone promoted by Fe-Mn-Cu/γ-Al2O3 (Cat) in a rotating packed bed (RPB) for the first time. The results showed that the value of the overall decomposition rate constant of ozone (Kc) and overall volumetric mass transfer coefficient (KLa) are 4.28×10-3 s-1 and 11.60×10-3 s-1 respectively at an initial pH of 6, β of 40, of 60 mg·L-1 and QL of 85 L·h-1 in deionized water, respectively. Meanwhile, the Kc and KLa values of Fenhe water are 0.88×10-3 s-1 and 2.51×10-3 s-1 lower than deionized water, respectively. In addition, the Kc and KLa values in deionized water for the Cat/O3-RPB system are 44.86% and 47.41% higher than that for the Cat/O3-BR (bubbling reactor) system, respectively, indicating that the high gravity technology can facilitate the decomposition and mass transfer of ozone in heterogeneous catalytic ozonation and provide some insights into the industrial wastewater.
    Effect of pitched short blades on the flow characteristics in a stirred tank with long-short blades impeller
    Yongjun Wu, Pan You, Peicheng Luo
    中国化学工程学报. 2022, 45(5):  143-152.  doi:10.1016/j.cjche.2021.11.010
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    This work focuses on the design improvement of the long-short blades (LSB) impeller by using pitched short blades (SBs) to regulate the flow field in the stirred vessel. After mesh size evaluation and velocity field validation by the particle image velocimetry, large eddy simulation method coupled with sliding mesh approach was used to study the effect of the pitched SBs on the flow characteristics. We changed the inclined angles of the SBs from 30° to 60° and compared the flow characteristics when the impeller was operated in the down-pumping and up-pumping modes. In the case of down-pumping mode, the power number is relatively smaller and vortexes below the SBs are suppressed, leading to turbulence intensification in the bottom of the vessel. Whereas in the case of up-pumping mode, the axial flow rate in the center increased significantly with bigger power number, resulting in more efficient mass exchange between the axial and radial flows in the whole vessel. The LSB with 45° inclined angle of the SBs in the up-pumping mode has the most uniform distributions of flow field and turbulent kinetic energy compared with other impeller configurations.
    Formation dynamics and size prediction of bubbles for slurry system in T-shape microchannel
    Zhen Chen, Chunying Zhu, Taotao Fu, Xiqun Gao, Youguang Ma
    中国化学工程学报. 2022, 45(5):  153-161.  doi:10.1016/j.cjche.2021.08.007
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    The bubble formation dynamics and size manipulation in the slurry of polystyrene microspheres in the microfluidic T-junction were visually investigated by a high-speed camera. Based on the evolution of the bubble neck with time, the formation process of bubbles is divided into three stages: filling, squeezing and pinch-off. The particle concentration has an obvious effect on the squeezing stage, while less impact on the filling and pinch-off stages. In the squeezing stage, the evolution of the dimensionless minimum neck width of bubbles with time could be described by a power-law relationship. The increase of the particle concentration or continuous phase flow rate could lead to the increase of body flow of the continuous phase and the enhancement of the squeezing force acted on the bubble neck, correspondingly, the power-law index α in the squeezing stage enlarges. Moreover, the bubble size increases with the increase of the gas phase flow rate and the decrease of the particle concentration and continuous phase flow rate. However, the effect of the particle concentration on the bubble size weakens with the increase of the continuous phase flow rate. In addition, a new prediction correlation of the bubble size for the slurry system in a T-shape microchannel was proposed with good prediction accuracy.
    Coupling effect of bifunctional ZnCe@SBA-15 catalyst in 1,3-butadiene production from bioethanol
    Zheng Wang, Sijia Li, Shengping Wang, Jiaxu Liu, Yujun Zhao, Xinbin Ma
    中国化学工程学报. 2022, 45(5):  162-170.  doi:10.1016/j.cjche.2021.02.025
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    A series of bifunctional ZnCe@SBA-15 catalysts with different Zn/Ce ratios were prepared by a solid-state grinding strategy and used in the conversion of ethanol to 1,3-butadiene (ETB). For the supported metal oxides, ZnO serves as the active sites for the dehydrogenation of ethanol, and CeO2 promotes the aldol-condensation reaction. Based on the results of Py-FTIR and NH3-TPD, it suggests that the yield of 1,3-butadiene is positively correlated with the number of weak Lewis acid sites on the catalyst surface, given their benefit for aldol-condensation reactions. The catalyst with an optimal Zn/Ce ratio of about 1:5 has the highest concentration of weak Lewis acid. Coupling with the ZnO sites, it contributes to a 98.4% conversion of ethanol and a 45.2% selective of 1,3-butadiene under relatively mild reaction conditions (375 ℃, 101.325 kPa, and 0.54 h-1).
    Enhanced recycling performance of bimetallic Ir-Re/SiO2 catalyst by amberlyst-15 for glycerol hydrogenolysis
    Xin Ren, Li Leng, Yueqiang Cao, Jing Zhang, Xuezhi Duan, Xueqing Gong, Jinghong Zhou, Xinggui Zhou
    中国化学工程学报. 2022, 45(5):  171-181.  doi:10.1016/j.cjche.2021.07.015
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    Recycling performance of heterogeneous catalysts is of crucial importance especially for a batch reaction system. In this work, we demonstrate a strategy for enhancing recycling performance of Ir-Re/SiO2 catalyst synergized with amberlyst-15 in glycerol hydrogenolysis to produce 1,3-propanediol. Comprehensive characterization results reveal that the Re sites in the Ir-Re/SiO2 catalyst undergo irreversible segregation and oxidation. These hinder the formation of active Re—OH species and thus contribute to a complete and irreversible deactivation. However, the introduction of amberlyst-15 into the reactant mixture can restrain the oxidation process of Re sites and favor the formation of Re—OH species, and thus significantly enhance the catalytic recycling performance. The results demonstrated here could guide the development of excellent bimetallic catalysts with the desirable recycling performances for the reaction.
    Mesopore-encaged V-Mn oxides: Progressive insertion approach triggering reconstructed active sites to enhance catalytic oxidative desulfuration
    Fu Yang, Ruyi Wang, Shijian Zhou, Xuyu Wang, Yan Kong, Shuying Gao
    中国化学工程学报. 2022, 45(5):  182-193.  doi:10.1016/j.cjche.2021.05.015
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    The oxidative desulphurization (ODS) has become mainly popular by rapid catalytic oxidation of dibenzothiophene (DBT) relied on efficient heterogeneous catalyst. V-based catalytic active species were regarded as the potential option in the activity-preferred ODS systems. Herein, we reported the re-dispersion of vanadium oxide (VOx) on the mesoporous silica modified with manganese oxide (Mn3O4) through one progressive insertion approach of metal oxides in the silica. Impressively, mesopore-encaged vanadium-manganese oxides in the silica (VMn-MS) as the admirable output of excellent ODS catalyst was demonstrated compared to other monometal-modified counterparts and one-pot implanted one. The characterization results revealed the post-implanted VOx species not only deposited around the pre-covered Mn3O4 on the mesoporous surface but also inserted the surface layer of Mn3O4 inducing the amorphous evolution of aggregated Mn3O4 and the reconstruction of final active sites. This integrated approach made the reconstructed active species afford more exposed catalytic sites and the tailored surface redox cycles owing to the electronic communication of V-Mn. The catalytic results demonstrated the excellent catalytic desulphurization efficiency (~100%) during 60 min at 80 ℃, which made the sulphur content reduce to 6 mg·L-1, remarkably superior to other comparative samples. The outstanding catalytic performance of VMn-MS catalyst can be ascribed to the synergistic effect of V-Mn dual metals rendering two different reaction pathways, which includes free-radical reaction and ring-forming reaction, where Mn site acted as active center triggering reactive free radicals which could be further optimized by surrounded V sites around Mn sites to promote the ODS process.
    Highly permeable reverse osmosis membranes incorporated with hydrophilic polymers of intrinsic microporosity via interfacial polymerization
    Jing Dou, Shuo Han, Saisai Lin, Zhikan Yao, Lian Hou, Lin Zhang
    中国化学工程学报. 2022, 45(5):  194-202.  doi:10.1016/j.cjche.2021.05.002
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    Enhancing the water permeation while maintaining high salt rejection of existing reverse osmosis (RO) membranes remains a considerable challenge. Herein, we proposed to introduce polymer of intrinsic microporosity, PIM-1, into the selective layer of reverse osmosis membranes to break the trade-off effect between permeability and selectivity. A water-soluble a-LPIM-1 of low-molecular-weight and hydroxyl terminals was synthesized. These designed characteristics endowed it with high solubility and reactivity. Then it was mixed with m-phenylenediamine and together served as aqueous monomer to react with organic monomer of trimesoyl chloride via interfacial polymerization. The characterization results exhibited that more “nodule” rather than “leaf” structure formed on RO membrane surface, which indicated that the introduction of the high free-volume of a-LPIM-1 with three dimensional twisted and folded structure into the selective layer effectively caused the frustrated packing between polymer chains. In virtue of this effect, even with reduced surface roughness and unchanged layer thickness, the water permeability of prepared reverse osmosis membranes increased 2.1 times to 62.8 L·m-2·h-1 with acceptable NaCl rejection of 97.6%. This attempt developed a new strategy to break the trade-off effect faced by traditional polyamide reverse osmosis membranes.
    Efficient conversion of benzene and syngas to toluene and xylene over ZnO-ZrO2&H-ZSM-5 bifunctional catalysts
    Xiao Zhao, Xuan Shi, Zhongshun Chen, Long Xu, Chengyi Dai, Yazhou Zhang, Xinwen Guo, Dongyuan Yang, Xiaoxun Ma
    中国化学工程学报. 2022, 45(5):  203-210.  doi:10.1016/j.cjche.2021.05.028
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    A series of ZnO-ZrO2 solid solutions with different Zn contents were synthesized by the urea co-precipitation method, which were coupled with H-ZSM-5 zeolite to form bifunctional catalysts. As a new benzene alkylation reagent, syngas was used instead of methanol to realize the efficient conversion of syngas and benzene into toluene and xylene. A suitable ratio of ZnO-ZrO2 led to the significant improvement in the catalytic performance, and a suitable amount of acid helped to increase the selectivity of toluene/xylene and reduce the selectivity of the by-products ethylbenzene and C9+ aromatics. The highest benzene conversion of 89.2% and toluene/xylene selectivity of 88.7% were achieved over 10% ZnO-ZrO2&H-ZSM-5 (Si/Al = 23) at a pressure of 3 MPa and a temperature of 450 ℃. In addition, the effect of the zeolite framework structure on product distribution was examined. Similar to the molecular dynamics of aromatic hydrocarbons, H-ZSM-5 zeolites comprise 10-membered-ring pores, which are beneficial to the activation of benzene; hence, the conversion of benzene is higher. H-ZSM-35 and H-MOR zeolites exhibited small eight-membered-ring channels, which were not conducive to the passage of benzene; hence, the by-product ethylbenzene exhibits a higher selectivity. The distance between the active centers of the bifunctional catalysts was the main factor affecting the catalytic performance, and the powder mixing method was more conducive to the conversion of syngas and benzene.
    Investigation on hydrate growth at the oil–water interface: In the presence of asphaltene
    Guangchun Song, Yuanxing Ning, Yuxing Li, Wuchang Wang
    中国化学工程学报. 2022, 45(5):  211-218.  doi:10.1016/j.cjche.2021.03.019
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    Natural gas hydrates can readily form in deep-water oil production processes and pose a great threat to the oil industry. Moreover, the coexistence of hydrate and asphaltene can result in more severe challenges to subsea flow assurance. In order to study the effects of asphaltene on hydrate growth at the oil–water interface, a series of micro-experiments were conducted in a self-made reactor, where hydrates nucleated and grew on the surface of a water droplet immersed in asphaltene-containing oil. Based on the micro-observations, the shape and growth rate of the hydrate shell formed at the oil–water interface were mainly investigated and the effects of asphaltene on hydrate growth were analyzed. According to the experimental results, the shape of the water droplet and the interfacial area changed significantly after the formation of the hydrate shell when the asphaltene concentration was higher than a certain value. A mechanism related to the reduction of the interfacial tension caused by the absorption of asphaltenes on the interface was proposed for illustration. Moreover, the growth rate of the hydrate shell decreased significantly with the increasing asphaltene concentration under experimental conditions. The conclusions of this paper could provide preliminary insight how asphaltene affect hydrate growth at the oil–water interface.
    CFD simulation study of the effect of baffles on the fluidized bed for hydrogenation of silicon tetrachloride
    Ning Liu, Xingping Liu, Fumin Wang, Feng Xin, Mingshuai Sun, Yi Zhai, Xubin Zhang
    中国化学工程学报. 2022, 45(5):  219-228.  doi:10.1016/j.cjche.2021.04.003
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    In this study, the effect of channel baffles and louver baffles on the flow pattern in the large-scale industrial fluidized beds was studied by computational fluid dynamics (CFD) methods. Then, the effect of flow pattern on the chemical reaction performance was studied for the first time. Simulation results showed that the gas velocity distributed more uniformly, solid particles dispersed more homogeneously and aggregation scarcely occurred in the fluidized bed with louver baffles than that with channel baffles. The residence time distribution indicated that louver baffles remarkably suppressed gas back-mixing in comparison with channel baffles. The reasonable agreements of pressure distribution and reaction results between the simulation in the bed with channel baffles and the data on a large-scale industrial apparatus demonstrated the accuracy of the CFD model. The predicted conversion of SiCl4 in the bed with louver baffles (27.44%) was higher than that with channel baffles (22.69%), indicating that louver baffles markedly improved the performance of the fluidized bed. This study could provide useful information for future structural improvements of baffles in large-scale fluidized beds.
    Oil droplet movement and micro-flow characteristics during interaction process between gas bubble and oil droplet in flotation
    Shenglin Yan, Yan Zhang, Chong Peng, Xiaoyong Yang, Yuan Huang, Zhishan Bai, Xiao Xu
    中国化学工程学报. 2022, 45(5):  229-237.  doi:10.1016/j.cjche.2021.03.014
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    Flotation is an efficient pre-treatment technology for oily water. In this work, the interaction process between the moving oil droplet and the gas bubble was studied by high-speed camera and Bassset-Boussinesq-Oseen (BBO) theoretical model, and the experimental and simulation results of the oil droplet trajectory were compared. Moreover, the micro-particle image velocimetry system was utilized to observe the flow inside and outside of the moving oil droplet. The results show that the BBO model with the mobile bubble’s surface can reflect the velocity change trend of the oil droplet during the interaction process between the moving oil droplet and the gas bubble, but there are some significant differences between the experimental and simulation results. While the oil droplet is moving on the bubble’s surface, the velocity of the area near the contact point of oil droplet–gas bubble is less than that of the other areas inside the oil droplet. Meanwhile, the flow of water above the oil drop is more biased towards the gas bubble.
    Fabrication and characterization of hierarchical porous Ni2+ doped hydroxyapatite microspheres and their enhanced protein adsorption capacity
    Yaling Li, Hao Ai, Liangzhi Qiao, Yinghong Wang, Kaifeng Du
    中国化学工程学报. 2022, 45(5):  238-247.  doi:10.1016/j.cjche.2021.03.020
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    Hydroxyapatite (HAP) is a common bio-adsorbent, which performance depends heavily upon its morphology and microporous structure. In this study, a novel synthesis strategy was proposed for hierarchical porous HAP microspheres by a simple “one-pot” hydrothermal reaction. In the strategy, L-glutamic acid serves as soft template to modulate the morphology and inner crystalline of HAP. To evaluate the application potential, doping Ni2+ on hierarchical porous HAP microspheres gives metal chelated affinity adsorbents. The prepared adsorbents show a perfect spherical shape, particles size of 96.6 μm, relatively specific surface area of 48.5 m2·g-1 and hierarchical pores (mesopores: 4 nm and macropores: 53 nm). By the adsorption evaluation, it reveals that the Ni2+-HAP adsorbents have high adsorption capacities of 275.11 and 97.55 m2·g-1 for hemoglobin and bovine serum albumin, respectively, which is comparable to other similar adsorbent. Therefore, this work provides a promising method for high-efficiency hydroxyapatite microspheres for proteins purification.
    Innovative hydrophobic/hydrophilic perfluoropolyether (PFPE)/polyvinylidene fluoride (PVDF) composite membrane for vacuum membrane distillation
    Jun Pan, Xianli Xu, Zhaohui Wang, Shi-Peng Sun, Zhaoliang Cui, Lassaad Gzara, Iqbal Ahmed, Omar Bamaga, Mohammed Albeirutty, Enrico Drioli
    中国化学工程学报. 2022, 45(5):  248-257.  doi:10.1016/j.cjche.2021.03.018
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    Though membrane distillation (MD) has gained more and more attention in the field of desalination, the wetting phenomenon was still a non-negligible problem. In this work, a method combined dip-coating and UV in situ polymerization for preparing hydrophobic/hydrophilic perfluoropolyether (PFPE)/polyvinylidene fluoride composite membranes. This composite membrane consisted of a top thin hydrophobic coating layer and hydrophilic substrate membrane. In terms of anti-wetting properties, contact angle and liquid entry pressure of all composite membranes (except for those based on 0.45 μm) exceeded 160° and 0.3 MPa, respectively. In particular, the desalination performance was tested in vacuum membrane distillation tests by feeding 3.5% (mass) saline solution (NaCl) at 60 ℃. The composite membranes with larger support pore size and lower PFPE content had higher membrane distillation flux. And for stability tests (testing the 0.22 μm membrane coated by 5% (mass) PFPE), the highest MD flux 29.08 kg·m-2·h-1 and stable salt rejection (over 99.99%) during the period. Except that, the effects of coating material concentration and pore sizes of substrate membrane were also investigated for surface morphology and topography, porosity, mechanical strength and pore size characteristics. This work provided a simple and effective alternative to prepare excellent hydrophobic composite membranes for MD applications.
    Spray-drying assisted layer-structured H2TiO3 ion sieve synthesis and lithium adsorption performance
    Minxia Liu, Dang Wu, Dongling Qin, Gang Yang
    中国化学工程学报. 2022, 45(5):  258-267.  doi:10.1016/j.cjche.2021.07.003
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    A spray-drying assisted solid-state method to prepare spherical layer-structured H2TiO3 ion sieve (LSTIS) particles is reported herein. The effects of synthesis parameters (calcination temperature, calcination time, and the lithium-titanium molar ratio) on adsorption–desorption performance (the delithiation ratio, titanium dissolution loss, and the adsorption capacity) were investigated. The as-prepared LSTIS exhibited an equilibrium adsorption capacity of 30.08 mg·g-1 (average of 25.85 mg·g-1 over 5 cycles) and ultra-low titanium dissolution loss of less than 0.12% (average of 0.086% over 5 cycles). The LSTIS showed excellent selectivity toward Li+ in Na+, K+, Mg2+, and Ca2+ coexisting saline solutions where its adsorption capacity reached 27.45 mg·g-1 and the separation factors of Li+ over the coexisting cations exceeded 100. The data suggests that the LSTIS is promising to competitively enrich Li+ from saline solutions.
    Numerical study on hydrodynamic characteristics of spherical bubble contaminated by surfactants under higher Reynolds numbers
    Tao Sun, Mingjun Pang, Yang Fei
    中国化学工程学报. 2022, 45(5):  268-283.  doi:10.1016/j.cjche.2021.04.002
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    It is of significance to investigate deeply the hydrodynamic features of the bubble contaminated by impurities in view of the fact that the industrial liquid is difficult to keep absolutely pure. On the basis of the finite volume method, the bubble interface contaminated by the surfactant (1-pentanol) is achieved through solving the concentration transport equations in liquid and along the bubble interface, and solving the absorption and desorption equation at the bubble interface. And the three-dimensional momentum equation is solved at the same time. It is investigated in detail on the influence of interfacial contamination degrees (described with the cap angle θ) on hydrodynamic characteristics of the spherical bubble when the bubble Reynolds number (Re) is larger than 200. The θ is realized by changing the surfactant concentration (C0) in liquid. The present results show that the hydrodynamic characteristics, such as interfacial concentration, interfacial shear stress, interfacial velocity and wake flow, are related to both Re and C0 for the contaminated bubble. When C0 is relatively low in liquid (i.e., the contamination degree of the bubble interface is relatively slight), the hydrodynamic characteristics of the bubble can still keep the 2D features even if Re > 200. The decrease of θ or the increase of Re can promote the appearance of the unsteady wake flow. For the present investigation, when Re > 200 and θ ≤ 60°, the hydrodynamic characteristics of the bubble show the 3D phenomena, which indicates that axisymmetric model is no longer valid.
    Insights into the cross-amyloid aggregation of Aβ40 and its N-terminal truncated peptide Aβ11-40 affected by epigallocatechin gallate
    Yue Liang, Wenjuan Wang, Yan Sun, Xiaoyan Dong
    中国化学工程学报. 2022, 45(5):  284-293.  doi:10.1016/j.cjche.2021.04.018
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    Inhibition of protein misfolding and aggregation is a great challenge in the field of biochemical and biopharmaceutical engineering. Alzheimer's disease (AD) is a protein-misfolding disease, and the interactions between 40-amino-acid-residue β-amyloid peptide (Aβ40) and its N-terminal truncated peptide Aβ11-40 demonstrate that Aβ11-40 may play an important role in the pathological process of AD. However, the effect of inhibitors on Aβ11-40 aggregation and on the cross-amyloid aggregation (co-assembly) between Aβ40 and Aβ11-40 has never been studied. Herein, coaggregation and seeding interactions between Aβ40 and Aβ11-40 as well as the effect of epigallocatechin gallate (EGCG), a small molecule inhibitor, on the cross-amyloid aggregation have been investigated by extensive analyses. It is found that Aβ11-40 participates in the aggregation of Aβ40 and leads to the formation of coaggregates that contain less β-sheet structures than pure Aβ40 aggregates. The aggregation kinetics along with morphologies and secondary structures of the coaggregates are also significantly affected by the Aβ40/Aβ11-40 ratio. EGCG accelerates the nucleation of Aβ40 but retards that of Aβ11-40 by affecting their elongation and secondary nucleation processes in solution and on solid surfaces. Meanwhile, EGCG makes the conformations of the seeding-induced Aβ aggregates more compact, especially for the homologous seedings. Isothermal titration calorimetry measurement indicates that hydrophobic interactions mainly contribute to the inhibition of the two Aβ isoforms by EGCG. The findings of this research have provided new insights into Aβ aggregation and the effect of an important inhibitor and the results would benefit in the development of potent inhibitors against co-assembly of different amyloid proteins.
    Solubility determination and thermodynamic modeling of bis-2-hydroxyethyl terephthalate (BHET) in different solvents
    Haoyu Yao, Dongxia Yan, Xingmei Lu, Qing Zhou, Yinan Bao, Junli Xu
    中国化学工程学报. 2022, 45(5):  294-300.  doi:10.1016/j.cjche.2021.03.024
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    Studies on the degradation process of waste polyethylene terephthalate (PET) have become increasingly mature, but there are relatively few studies on the separation of degradation products. The products contain many components and the separation of which is difficult. Therefore, the study on phase equilibrium thermodynamics of bis-2-hydroxyethyl terephthalate (BHET) is of great theoretical significance and practical value to provide basic data for the BHET crystallization separation. In this work, the degraded products were purified and characterized. The solubility of BHET in methanol, ethanol, ethylene glycol, water and the mixture of ethylene glycol + water were determined by static method. The experimental results were correlated with different models, such as ideal solution (IS) model, λh equation, Apelblat equation and NRTL model. Based on the van't Hoff equation, the mixing Gibbs energy, enthalpy and entropy were calculated. From this work, the basic data which can be used to guide the crystallization process of BHET were obtained, including solubility data, correlation model and thermodynamic properties.