Table of Content

    30 June 2022, Volume 24 Issue 2
    2022, 24(2):  0. 
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    content of this issue
    Amorphous Catalysts for Electrochemical Water Splitting
    Zhang Cong, Wang Shuaiyang, Rong Junfeng, Mi Wanliang
    2022, 24(2):  1-13. 
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    Hydrogen production by water electrolysis is an important route for generating green hydrogen. However, the development of efficient and inexpensive electrocatalysts is crucial for future industrial applications. Amorphous catalysts possess a large specific surface area with abundant structural defects. In addition, their structures can be tuned to provide more efficient active sites, leading to superior water electrolysis activity compared with their crystalline counterparts. In this review, we summarize recent progress on amorphous electrocatalysts for water splitting, with a focus on the reaction mechanisms under both acidic and alkaline conditions, catalyst synthesis, and the application of these catalysts to the hydrogen and oxygen evolution reactions. Moreover, we highlight the current challenges and promising opportunities relating to amorphous catalysts for electrochemical water splitting.
    Process Research
    Tetralin Hydrocracking Reaction Network to Single Ring Aromatics on Bifunctional Catalysts
    Ju Xueyan, Huang Zhen, Zhang Rui, Wang Lixin, Hu zhihai, Li Dadong
    2022, 24(2):  14-22. 
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    Conversion of LCO (light cycle oil) to BTX (benzene, toluene, and xylene) is an economically valuable method for refineries. However, this approach still faces difficulties as the main reactions are not clearly understood. Here we study the detailed hydrocracking pathway of typical reactants, 1-methylnaphthalene and tetralin, through molecular simulations and experiments to improve our understanding of the conversion process of LCO to BTX. Molecular simulations demonstrate that the rate-determining step is the isomerization pathway of six-membered ring to five-membered ring in tetralin as its activation energy (ΔEa) is the highest among all the reactions and the order of ΔEa of reactions is isomerization > ring-opening ≈ side-chain cleavage. The results of experiments show that with the increase in reaction depth, i.e., through a high temperature (350 – 370 °C) and low LHSV (4.5 – 6.0 h−1), isomerization, ring-opening, and side-chain  cleavage reactions occurred, thus improving the selectivity and yield of alkyl aromatics.
    Upgradation of heavy crude oil via hydrodynamic cavitation technique through variations in asphaltenes
    Li Kang, Han Haibo, Lei Jie, Wang Youhe, Li Dekun, Mark J. Rood, Fazle Subhan, Yan Zifeng
    2022, 24(2):  23-33. 
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    In this work, Saudi heavy crude oil (SHCO) was upgraded by hydrodynamic cavitation bubble collapse technique. Collapse of cavitation bubbles instantly produces extreme effects such as high temperature, pressure, high jet flow and strong shear force, which played significant role for upgradation process. The results revealed that the properties of SHCO such as, viscosity and Conradson carbon residue were reduced from 13.61 mm2/s, 7.16% to 7.22 mm2/s, 6.48%, respectively. True boiling point distillation findings showed that the vacuum residue (VR) was also decreased by 1%. APPI FT-IR MS, XRD, DLS, FT-IR, and SEM were employed to characterize the molecular composition, crystalline structure, asphaltene aggregates particle size distribution, functional groups, and morphology, respectively to understand the effect on asphaltenes by hydrodynamic cavitation technique. The obtained results demonstrated that hydrodynamic cavitation upgradation reduced the interaction forces between asphaltenes molecules, making the crystalline structure of asphaltenes aggregates weak, reduce the degree of association of aromatic compounds in SHCO and asphaltenes, and decrease the particle size distribution. The delayed coking properties of the VR was further investigated to feedback the upgradation effect. The coke yield decreased by 1.85%, and the liquid and gas yields increased by 1.52% and 0.33%, respectively. Hence, the improvement in asphaltenes properties and structural characteristics can effectively improve its processing performance.
    Acid Desulfurization Exploration of High-Sulfur Petroleum Coke Intensified by Pre-calcination, H2O2 treatment, and Ultrasound
    Wang Gang, Mao Qiuyun, Liu Wei, Yu Zhou, Zhong Qifan
    2022, 24(2):  34-45. 
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    The present investigation reported the acid desulfurization of high sulfur petroleum coke (petcoke) powder intensified by pre-calcination, H2O2, and ultrasound combing X-ray photoelectron spectroscopy, thermal gravity/ derivative thermogravimetry, pore distribution, specific surface area, energy-dispersive X-ray spectroscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy analyses. Results showed that pre-calcination at 800 °C for 6 h, mixing with HNO3 (8 mol/L) + H2O2 (2 mol/L) solution at a liquid-to-solid ratio of 10 ml/g, 60 °C, and 40 kHz ultrasound power of 400 W assisted for at least 6 h, and over 45% of sulfur atoms in Tianjin coke and Qilu coke (particle size < 0.1 mm) were removed efficiently. Besides, the specific surface area of petcoke particles increased from 0.7 m2/g to 301.49 m2/g. After desulfurization, the pore distribution of petcoke particles was concentrated more on smaller pores with micropores formed. This allowed desulfurized petcoke to be superior to the preparation of activated carbon and petcoke gasification. Reactive molecular dynamics (ReaxFF) simulation results revealed HNO3 continuously oxidized the carbon atoms adjacent to S in petcoke macromolecules, and promoted S to be removed from petcoke via destroying the stable structure between C and S. The transformation behavior of thiophene S could be summarized as follows: thiophene S → carbon branched chain S → CO2S → C2O2S → C2O3NS → C2O4S → CO2S.
    Removal of Heteroaromatic Sulfur Compounds by a Non-noble Metal Fe Single-atom Adsorbent
    Lü Yanjun, Wen Jie, Gong Qinmei, Zhang Lianhong, Li Airong, Arshid Mahmood Ali, Zhang Hui
    2022, 24(2):  46-57. 
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    Sulfur-containing compounds (SCCs) need to be removed from fuels due to their negative effects on the environment and catalytic stability. In this study, a novel non-noble metal Fe single-atom adsorbent (SA-Fe/CN) was synthesized using a core-shell strategy and applied to the adsorptive removal of benzothiophene (BT) and dibenzothiophene (DBT). Simultaneously, the adsorption isotherms, thermodynamics, and kinetics of DBT and BT on SA-Fe/CN were studied. SA-Fe/CN exhibited a strong adsorption affinity to DBT, and the isothermal equilibrium was well described by the Langmuir isotherm model. Thermodynamic analysis showed that the Gibbs free energy values were negative (ΔG0 <0), illustrating that the adsorption process for DBT and BT was favorable and spontaneous. Adsorption kinetics was analyzed using pseudo-first-order and pseudo-second-order, the results displayed that the adsorption process conformed to the pseudo-second-order kinetic model with higher R2 values (0.9994, 0.9987). The adsorption results also indicated that the adsorption capacity of SA-Fe/CN for DBT and BT reached 163.21 mg-S/g and 93.82 mg-S/g, respectively, which might be attributed to the highly active sites of the single atom and the electrostatic interaction with the sulfide. Therefore, this study proves SA-Fe/CN is a promising adsorbent for DBT removal.
    Scientific Research
    High-performance composite epoxy coating based on 2D Co2(OH)2BDC and electrospinning-made PAN nanofiber membrane
    Zhao Huarong, Zhang Yueshuang, Gan Shaojie, Yue Qiankun, Liu Zan, Cheng Zhilin
    2022, 24(2):  58-67. 
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    Based on a two-dimensional (2D) Co–MOF (Co2(OH)2BDC) with a self-contained organic interface and low conductivity, a composite epoxy coating (2D Co2(OH)2BDC-PAN/EP) was constructed by a two-step preparation. First, a polyacrylonitrile (PAN) nanofiber membrane was electrospuned on the surface of Q235 steel, followed by coating using the epoxy coating (EP) containing 2D Co2(OH)2BDC. The 2D Co2(OH)2BDC-PAN/EP composite epoxy coatings showed robust mechanical performance and excellent corrosion resistance capacity.
    Study on the Influence of Ethanol Addition on the Spray Auto-ignition Properties of Gasoline and Its Relationship with Octane Number
    Wang Jun, Yang He, Hu Xiaoming, Song Haiqing, Zhang Ran, Tian Huayu
    2022, 24(2):  68-75. 
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    In this study, the spray auto-ignition properties of binary primary reference fuels (PRFs) of 2,2,4-trimethylpentane and n-heptane with different research octane numbers (RONs) were measured according to the industry standard NB/SH/T 6035 to determine their ignition delay times at various initial temperatures. Furthermore, the auto-ignition properties were investigated after blending the PRFs with various amounts of ethanol. The results revealed a very good correlation between the derived cetane number and the RON for the PRFs in both the presence and absence of ethanol. In addition, a concept of ignition delay sensitivity was developed for ethanol-containing fuels that exhibited a close relationship with the octane sensitivity, which is defined as the RON minus the motor octane number (MON). Finally, the developed method was applied to conveniently estimate the RON and MON values of several ethanol-containing fuels by simply measuring their autoignition properties.
    Industrial Preparation and Acid Resistance of Ultra-stable Y Zeolite with Small Cell Size Produced by Gas-phase Method
    Zhang Jing, Jia Jishun, Sha Hao, Lu Guanqun, Yan Jiasong, Wang Shengji, Zhou Lingping
    2022, 24(2):  85-90. 
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    The zeolite HSY-S with small cell size prepared by gas-phase ultra-stable method had been researched and developed, and industrial preparation tests of HSY-S had been successfully carried out for the first time in the world. The acid resistance of HSY-S prepared in industrial was investigated by acid solutions with different pH values. The structures and properties of HSY-S and its acid-treated samples were characterized by XRD, XRF,BET and IR. The results showed that the zeolite HSY-S has the characteristics of high crystallinity, good stability, large specific surface area and good acid resistance.
    Controlled growth of NiMoO4 Nano-Rods on carbon cloth as advanced electrode for hydrogen evolution reaction (HER) process in alkaline and simulated sea water electrolyte
    Jiang Bolong, Shi Shunjie, Cui Yanyan, Jiang Nan
    2022, 24(2):  91-100. 
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    A series of NiMoO4-NRs/CC-x composites with different NiMoO4-NRs loadings (x) was synthetized for efficient HER through directly growing active NiMoO4 nano-rods (NRs) on carbon cloth (CC) by a simple hydrothermal reaction coupled with an annealing treatment. The resulting NiMoO4-NRs/CC-x composites were directly used as electrode for alkaline medium and simulated sea water electrolysis, respectively. Results showed that among NiMoO4-NRs/CC-x composites, the NiMoO4-NRs/CC-10 composite was found to possess the highest HER activity with the overpotential of 244.8 mV at 10 mA/cm2, Tafel slope of 95 mV/dec, fastest charge transfer (Rct<1Ω) and good stability in alkaline medium. Even in the simulated seawater, the NiMoO4-NRs/CC-10 composite showed a relatively high stability. The outstanding HER activity and stability can be originated from the strong interaction between Ni and Mo in NiMoO4 nano-rods as well as the fastest charge transfer and hydrogen reaction rate due to the synergistic effect of CC and NiMoO4 nano-rods.
    Simulation and Optimization
    A multi-objective optimization approach for the design of heat exchanger network (HEN) in process industries
    Tan Qiang, Chen Yuting, Xu Yanyan, Ye Shuang, Xiao Hao, Huang Weiguang
    2022, 24(2):  101-111. 
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    To simultaneously improve the quantity and quality of heat recovery in a heat exchanger network (HEN), this study conducts a theory analysis based on the first and second laws of thermodynamics. Under the premise of maximizing the heat recovery quantity of HEN, ?diss is used as an evaluation index to optimize the quality of heat recovery. Meanwhile, the total annual cost (TAC) is considered as another optimization objective to ensure the economic feasibility of the HEN. A superstructure-based multi-objective mixed integer non-linear programming approach is put forward to solve the trade-off between minimizing ?diss and minimizing TAC. This allows for the optimum HEN structure to be obtained. A well-studied example is solved to highlight the benefits of the proposed method.
    Modeling of C8 Aromatics Isomerization in a Radial Bed Reactor
    Gao Ninghan, Tang Xiaojin, Zhou Zhenhuan, Xu Jian
    2022, 24(2):  112-117. 
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    Reactor models were developed to describe the isomerization reaction process of C8 aromatics by applying a sixcomponent
    sequential reaction network. Lab-scale experimental data were used in an axial bed reactor model, and dynamic
    parameters were fitted by simulated annealing algorithm. In addition, industrial data and calculated dynamic parameters
    were used to determine the six-component concentration distributions using a radial reactor model. The influence of backmixing
    on reaction performance was investigated. It was found that the model considering back-mixing was much closer to
    the real industrial reaction process.
    Influence of structural composition on asphaltene self-diffusion coefficient in asphaltene-xylene system
    Yang Haiyang, Wang Chunlu, Ren Qiang, Wang Lixin, Yan Xuemin
    2022, 24(2):  118-125. 
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    Molecular simulations were carried out to investigate the self-diffusion coefficient of asphaltene in asphaltene-xylene systems which were used as heavy oil models. The self-diffusion behavior of asphaltene in asphaltene-xylene equilibrium system was mainly affected by the interaction between asphaltene molecules. The larger the interaction between the asphaltene molecules, the slower the diffusion of asphaltene. The interaction between asphaltene molecules mainly includes π-π interaction between aromatic rings and hydrogen bond interaction between strongly electronegative heteroatom groups. These results might provide theoretical guidance for viscosity reduction of heavy oil.
    Effects of combined stress from salt and herbicide on microbial remediation of soil contaminated by n-Hexadecane and phenanthrene
    Liu Bingkun, Zuo Shuai, Wang Ruirui, Dong Kangning, Zhang Xiuxia, Li Ruyue, Hao Boyu, Li Jing, Yin Linghao, Bai Yuhao, Song Jiayu, Gu Yingying, Sun Juan
    2022, 24(2):  126-137. 
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    In this study, physicochemical analysis, cluster analysis, high throughput sequencing were used to investigate the effects of combined salt and herbicide stress on microbial remediation of soil contaminated by n-Hexadecane and phenanthrene. Based on the physical and chemical properties of the soil, the differences in microbial quantity and enzyme activities were analyzed among the samples, and the influence on the distribution of soil community structure was mainly discussed. After 120 days of indoor simulated remediation, the cumulative degradation rate of n-hexadecane decreased by 94.92% (blank control), 96.96% (low concentration of salt and herbicide glyphosate stress), 65.07% (high concentration of salt and herbicide glyphosate stress), and that of phenanthrene decreased by 87.33% (blank control), 86.25% (low concentration of salt and herbicide glyphosate stress), 58.45% (high concentration of salt and herbicide glyphosate stress), respectively. The analysis of physical and chemical properties indicated that the combined stress of salt and herbicides could decrease the reduction efficiency of organic matter, total nitrogen, and total phosphorus, and also restrict the growth of microorganisms and enzyme activities. Cluster analysis implied that the non-stress group was similar to the low-concentration compound stress group during different repair periods, while the high-concentration compound stress group was quite different. High-throughput sequencing showed that dominant bacteria phyla changed from Firmicutes to Actinobacteria within 120 days of remediation.
    Visible light photocatalytic activity of TiO2 nanorods and its application in degrading organic pollutants
    He Jie, Shi Chaojie, Yang Zhengchun, Hou Qiang, Zhang Rui, Zhu Tianjia, Pan Peng, Zhang Ping
    2022, 24(2):  138-146. 
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    The FTO/TiO2 seed layer/TiO2 nanorods were prepared by ion beam deposition and hydrothermal methods. Under UV light, the photocurrent density of FTO/TiO2 seed layer/TiO2 nanorods can reach 1.39 mA/cm2, which is higher than that without seed layer and nanorods structure. Not only that, the FTO/TiO2 seed layer/TiO2 nanorods can also adsorb visible light, which overcomes the defect that traditional TiO2 can not absorb visible light. The photocurrent density of FTO/TiO2 seed layer/TiO2 nanorods can reach 0.21 mA/cm2 under visible light. The increased performance resulted from the deposition of the TiO2 seed layer, which can reduce the band gap of TiO2. FTO/TiO2 seed layer/TiO2 nanorods also exhibited high photodegradation ability for organic pollutant methylene blue (MB). Within 120 min, 77.3% MB can be degraded, and the degradation rates remained almost unchanged after four cycles. Not only that, compared with powdered photocatalysts, FTO/TiO2 seed layer/TiO2 nanorods is easy to recover, and it can be reused by rinsing it with water several times and drying it naturally after the reaction.
    Assembling superfine Bi3TaO7 particles into 2D Fe2O3 nanosheets for enhanced usability to purify aqueous tetracycline residues
    Liu Xiaoqing, Cheng Hongjun, Wang Zisha, Zhang Jian, Lan Yanhua, Wang Xiaojing
    2022, 24(2):  147-158. 
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    Composites of 2D/0D Fe2O3-Bi3TaO7 (FO-BTO) prepared by a hydrothermal method in which superfine Bi3TaO7 particles were mounted onto lamellae of Fe2O3 sheets could efficiently remove aqueous tetracycline (TC) residues. The optimal composite FO-3BTO had a TC removal rate of 95% in 120 min under solar light, and its overall properties were better than those of reported photocatalysts. According to XRD, HRTEM, XPS, SEM, PL, EIS, and photocurrent tests, Fe2O3 and Bi3TaO7 composites formed on effective S-scheme heterojunctions, and the tight contact structure contributed to the increase in efficiency of aqueous TC residue removal.