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Effects of substrate types on the transformation of heavy metal speciation and bioavailability in an anaerobic digestion system

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Journal of Environmental Sciences 2021年第3期33卷 361-372页

作者： Xiarong Zheng Kuanhuai Wu Pengju Sun Siyu Zhouyang Yuanpeng Wang Haitao Wang Yanmei Zheng Qingbiao Li department of chemical and Biochemical engineering College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China College of food and Biological engineering Jimei UniversityXiamen 361021China

chemical speciation can fundamentally affect the potential toxicity and bioavailability of heavy *** transformation of heavy metal speciation and change of bioavailability were investigated in an anaerobic digestion(AD)system using four different substrates(pig manure(PM),cattle manure(CAM),chicken manure(CHM)and rice straw(RS)).The results obtained indicated that the total contents of heavy metals in PM,CHM and GAM were higher than in RS and decreased in the order Zn>Cu>Ni>Pb>As>Cd in all ***,the speciation with the largest proportion for each heavy metal was the same both in the different substrates and the biogas *** them,Zn,Ni,Cd and As were mainly in the reducible fraction(F2),while Cu was mainly in the oxidizable fraction(F3)and Pb occurred predominantly in the residual fraction(F4).Our results further indicated that the AD process had a greater effect on the speciation of heavy metals in CHM and PM,but less on CAM and *** rates of change in bioavailability followed the order PM>CHM>CAM>*** in organic matter,humic acid or local metal ion environment as a result of AD were inferred as likely mechanisms leading to the transformation of heavy metal *** results enhanced our understanding of the behavior of heavy metals in AD and provided a new perspective for the treatment and disposal of the substrates.

关键词： Anaerobic digestion Heavy metal Speciation Bioavailability

Component analysis and risk assessment of biogas slurry from biogas plants

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Chinese Journal of chemical engineering 2022年第4期35卷 182-191页

作者： Lanting Ke Xiaobin Liu Bingqing Du Yuanpeng Wang Yanmei Zheng Qingbiao Li department of chemical and Biochemical engineering College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China College of food and Biology engineering Jimei UniversityXiamen 361021China

Massive amounts of biogas slurry are produced due to the development of biogas *** pollution features and the risk of biogas slurry were fully evaluated in this ***-one biogas slurry samples were collected from sixteen different cities and five different raw materials biogas plants(*** manure,swine manure,straw-manure mixture,kitchen waste and chicken manure).The chemical oxygen demand(COD),ammonia nitrogen(NH_(4)^(+)-N),anions(***^(-1),SO_(4)^(2-),NO_(3)^(-)and PO_(4)^(3-)),antibiotics(***,quinolones,β2-receptor agonists,macrolides,tetracyclines and crystal violet)and heavy metals(***,Cd,As,Cr,Hg,Zn and Pb)contents from these biogas slurry samples were systematically *** this basis,risk assessment of biogas slurry was also *** concentrations of COD,NH_(4)^(+)-N and PO_(4)^(3-) in biogas slurry samples with chicken manure as raw material were significantly higher than those of other raw ***,the biogas slurry from chicken manure raw material demonstrated the most serious eutrophication *** antibiotic contents in biogas slurry samples from swine manure were the highest among five raw materials,mostly sulphonamides,quinolones and *** slurry revealed particularly serious arsenic contamination and moderate potential ecological *** quadratic polynomial stepwise regression model can quantitatively describe the correlation among NH_(4)^(+)-N,PO_(4)^(3+) and heavy metals concentration of biogas *** work demonstrated a universal potential threat from biogas slurry that can provide supporting data and theoretical basis for harmless treatment and reuse of biogas slurry.

关键词： Biogas slurry Antibiotics Heavy metals Risk assessment

CONTINUOUS STIFFNESS MODE NANOINDENTATION RESPONSE OF POLY(METHYL METHACRYLATE) SURFACES

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Chinese Journal of Polymer Science 2013年第8期31卷 1096-1107页

作者： T. Iqbal B.J. Briscoe S. Yasin P.F. Luckham chemical engineering department University of Engineering & Technology chemical engineering department Imperial College

Indentation is a comparatively simple and virtually nondestructive method of determining mechanical properties of material surfaces by means of an indenter inducing a localized deformation. The paper present experimental results of the load-displacement curves, the hardness and the elastic modulus data, and associated analysis for poly（methyl methacrylate）（PMMA） surfaces as a function of contact displacement. The experimental results include continuous stiffness indentations performed using constant loading rate and constant displacement rate experiments. The continuous stiffness indentation involves continuous calculation of a material stiffness, and hence hardness and elastic modulus of surfaces, during discrete loading-unloading cycles, as in a conventional indentation routine, and in a comparatively smaller time constant, The dependence of the compliance curves, the hardness, the elastic modulus and the plasticity index upon the imposed penetration depth, the applied normal load and the deformation rate are described. Tip area and load frame calibrations for the continuous stiffness indentation are also reported. The paper includes practical considerations encountered during indentation of polymers specifically at low penetration depths. The experimental results show a peculiarly harder response of PMMA surfaces at the submicron （near to surface） layers.

关键词： Nanoindentation PMMA Hardness Modulus Continuous stiffness.

Investigation of the liquid recycle in the reactor cascade of an industrial scale ebullated bed hydrocracking unit

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Chinese Journal of chemical engineering 2019年第2期27卷 298-304页

作者： Eduard Manek Juma Haydary Institute of chemical and Environmental engineering Faculty of Chemical and Food Technology Slovak University of Technology

One of the commercial means to convert heavy oil residue is hydrocracking in an ebullated bed. The ebullated bed reactor includes a complex gas–liquid–solid backmixed system which attracts the attention of many scientists and research groups. This work is aimed at the calculation of the internal recycle flow rate and understanding its effect on other parameters of the ebullated bed. Measured data were collected from an industrial scale residual hydrocracking unit consisting of a cascade of three ebullated bed reactors. A simplified block model of the ebullated bed reactors was created in Aspen Plus and fed with measured data. For reaction yield calculation, a lumped kinetic model was used. The model was verified by comparing experimental and calculated distillation curves as well as the calculated and measured reactor inlet temperature. Influence of the feed rate on the recycle ratio(recycle to feed flow rate) was estimated. A relation between the recycle flow rate, pump pressure difference and catalyst inventory has been identified. The recycle ratio also affects the temperature gradient along the reactor cascade. Influence of the recycle ratio on the temperature gradient decreased with the cascade member order.

关键词： Residual hydrocracking Ebullated bed reactor Liquid recycle Aspen Plus Simulation

NHC-mediated photocatalytic para-selective C–H acylation of aryl alcohols: regioselectivity control via remote radical spiro cyclization

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Science China Chemistry 2025年

作者： Tinglei Zhang Lala Wang Xiaolin Peng Tianhui Liao Dongmei Chen Ting Tu Donghan Liu Ziye Cheng Shiqing Huang Shi-Chao Ren Xinglong Zhang Yonggui Robin Chi State Key Laboratory of Green Pesticide Key Laboratory of Green Pesticide and Agricultural Bioengineering Ministry of Education Guizhou University Qiannan Medical College for Nationalities School of Chemistry Chemical Engineering and Biotechnology Nanyang Technological University department of Chemistry The Chinese University of Hong Kong Institute of High Performance Computing Agency for Science Technology and Research

Friedel-Crafts reaction and transition-metal catalysis represent primary methodologies for arene acylation; however, suffer from certain limitations, such as electronic effect-dependent reactivity, regioselectivity issues, the necessity of directing group, and relatively exceptionally limited exploration in meta-and para-acylations. N-heterocyclic carbene(NHC) catalysis has recently emerged as a promising alternative strategy for arene acylation, offering distinct regioselectivity profiles that are challenging to achieve through known methods. Herein, an NHC-mediated photo-catalytic para-selective C–H acylation of aryl alcohols is disclosed. The reaction employs a remote radical-induced temporary spiro cyclization strategy, proceeding via tandem radical dearomatization, radical acylation, rearomatization processes. Combined experimental and computational mechanistic studies support the proposed reaction pathway and observe an exclusive para-selectivity regardless of the nature of the substituents on the substrates. Despite the less satisfactory yields, the current method exhibits non-electronic nature-based reactivity and regioselectivity, enabling quick access to acylated arenes that are difficult or impossible for reported methods.

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Effect of precipitants on Ni-CeO_2 catalysts prepared by a co-precipitation method for the reverse water-gas shift reaction

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Journal of Rare Earths 2013年第10期31卷 969-974页

作者：王路辉刘辉刘源陈英杨淑清 department of chemical engineering School of Petrochemical Technology and Energy Engineering Zhejiang Ocean University School of food and Pharmaceutical Zhejiang Ocean University department of Catalysis Sciences and Technology School of Chemical Engineering Tianjin University

A series of Ni-CeO2 catalysts were prepared by co-precipitation method with Na2CO3, NaOH, and mixed precipitant （Na2CO3：NaOH; 1：1 ratio） as precipitant, respectively. The effect of the precipitants on the catalytic performance, physical and chemical properties of Ni-CeO2 catalysts was investigated with the aid of X-ray diffraction （XRD）, Bmmaner-Emmett-Teller method （BET）, Fou- rier-transform infrared spectroscopy （FT-IR）, thermogravimetry （TG）, and H2-TPR characterizations. The Ni-CeO2 catalysts were exam- ined with respect to their catalytic performance for the reverse water-gas shift reaction, and their catalytic activities were ranked as： Ni-CeO2-CP （Na2CO3：NaOH=I：I）〉Ni-CeO2-CP（Na2CO3）〉Ni-CeO2-CP（NaOH）- Correlating to the characteristic results, it was found that the catalyst prepared by co-precipitation with mixed precipitant （Na2CO3：NaOH; 1：1 ratio） as precipitant hadthe most amount of oxygen vacancies accompanied with highly dispersed Ni particles, which made the corresponding Ni-CeO2-CP（Na2CO3：NaOH=I： 1） catalyst exhibit the highest catalytic activity. While the precipitant of Na2CO3 or NaOH resulted in less or no oxygen vacancies in Ni-CeO2 catalysts. As a result, Ni-CeO2-CP（Na2CO3） and Ni-CeO2-CP（NaOH） catalysts presented poor catalytic performance.

关键词： reverse water-gas shift reaction Ni-CeO2 catalyst co-precipitation oxygen vacancy precipitant rare earths

Facile and Controllable Assembly of Multiwalled Carbon Nanotubes on Polystyrene Microspheres

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Chinese Journal of Polymer Science 2014年第6期32卷 711-717页

作者：李云兴 Yan Gao Cheng Yang Zhao-qun Wang Gi Xue The Key Laboratory of food Colloids and Biotechnology Ministry of Education School of Chemical and Material Engineering Jiangnan University department of Polymer Science and engineering School of Chemistry and Chemical Engineering Nanjing University

Herein a facile and controllable heterocoagulation between polystyrene （PS） microspheres and multiwalled carbon nanotubes （MWCNTs） is introduced based on colloid thermodynamics. The MWCNTs play the role of steric stabilizer for stabilizing the metastable PS microspheres and thus immobilize spontaneously on the surface of PS microspheres. The synthesized MWCNTs-coated PS composite particles have been extensively characterized by scanning electron microscopy, transmission electron microscopy, thermogravimetry and Raman spectroscopy. The results indicate that the structure and morphology of the resultant MWCNTs-coated PS composite particles are significantly affected by the weight ratio of PS and MWNCTs and the amount of poly（vinylpyrrolidone） that is injected into PS dispersion before they are mixed with MWCNTs. Therefore, these composite particles have the potential to produce MWCNTs-based composite materials with controllable mass loading and dispersity of MWCNTs.

关键词： Multiwalled carbon nanotube Polystyrene microsphere Heterocoagulation Structural control Colloidthermodynamics.

Application of response surface methodology for optimization of purge gas recycling to an industrial reactor for conversion of CO_2 to methanol

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Chinese Journal of chemical engineering 2017年第5期25卷 676-687页

作者： Hadiseh Khalilpourmeymandi Azadeh Mirvakili Mohammad Reza Rahimpour Alireza Shariati department of chemical engineering School of Chemical and Petroleum EngineeringShiraz University department of chemical engineering School of Chemical and Petroleum EngineeringPersian Gulf University Shiraz University Natural Gas Engineering DepartmentSchool of Chemical and Petroleum Engineering

Nowadays, by the increasing attention to environment and high rate of fuel production, recycling of purge gas as reactant to a reactor is highly considered. In this study, it is proposed that the purge gases of methanol production unit, which are approximately15.018 t·h^(-1) in the largest methanol production complexes in the world, can be recycled to the reactor and utilized for increasing the production rate. Purge gas streams contain 63% hydrogen,20% carbon monoxide and carbon dioxide as reactants and 17% nitrogen and methane as inert. The recycling effect of beneficial components on methanol production rate has been investigated in this study. Simulation results show that methanol production enhances by recycling just hydrogen, carbon dioxide and carbon monoxide which is an effective configuration among the others. It is named as Desired Recycle Configuration(DRC) in this study. The optimum fraction of returning purge gas is calculated via one dimensional modeling of process and Response Surface Methodology(RSM) is applied to maximize the methanol flow rate and minimize the carbon dioxide flow rate. Simulation results illustrate that methanol flow rate increases by 0.106% in DRC compared to Conventional Recycle Configuration(CRC) which therefore shows the superiority of applying DRC to CRC.

关键词： Methanol synthesis Recycling purge gas streams Novel configuration Response surface methodology

Continuous Ethanol Production Through Fermentation with Glucose and Xylose by Immobilized Yeasts in Two Cascade Fixed Beds

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Chinese Journal of chemical engineering 1998年第1期6卷 54-62页

作者：邓旭岑沛霖 department of chemical engineering Xiamen University department of chemical engineering Zhejiang University

Glucose and xylose were used as mixed carbon sources for ethanol production by a cascade immobi-lized-cell *** the first fixed-bed reactor,immobilized *** was used to metabolize the glucoseanaerobically,and in the second fixed-bed column,the immobilized Pichia stipitis was applied to metabolize xy-lose *** effect of xylose on the glucose uptake by *** and the effect of ethanol on the xylosemetabolization by *** were studied.A mathematical model taking both tbe substrate and xylose inhibitioninto consideration was suggested for the description of the two-substrate fermentation process,and a total effec-tiveness factor η_s in the model was derived to take into account the mass transfer resistances of intra-particlesand liquid *** results are in fair agreement with the experimental data.

关键词： ethanol continuous fermentation mixed substrate kinetic model