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Effects of different Ca^(2+) behavior patterns in the electric field on membrane fouling formation and removal of trace organic compounds

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Journal of environmental sciences 2022年第1期34卷 292-300页

作者： Zhen Du Min Ji Ruying Li School of Environmental Science and Engineering Tianjin UniversityTianjin 300350China

The effects of Ca^(2+) on membrane fouling and trace organic compounds(TrOCs)removal in an electric field-assisted microfiltration system were investigated in the presence of Na^(+) alone for comparison.In the electric field,negatively charged bovine serum albumin(BSA)migrated towards the anode far away from the membrane surface,resulting in a 42.9%transmembrane pressure(TMP)reduction in the presence of Na^(+) at 1.5 V.In contrast,because of the stronger charge shielding of Ca^(2+),the electrophoretic migration of BSA was limited and led to a neglectable effect of the electric field(1.5 V)on membrane fouling.However,under 3 V applied voltage,the synergistic effects of electrochemical oxidation and bridging interaction between Ca^(2+) and BSA promoted the formation of denser settleable flocs and a thinner porous cake layer,which alleviated membrane fouling with a 64.5%decrease in TMP and nearly 100%BSA removal.The Tr OCs elimination increased with voltage and reached29.4%–80.4%at 3 V.The electric field could prolong the contact between Tr OCs and strong oxidants generated on the anode,which enhanced the Tr OCs removal.However,a stronger charge shielding ability of Ca^(2+) weakened the electric field force and thus lowered the Tr OCs removal.

关键词： Electric field Membrane fouling Ca^(2+) Flocs formation Trace organic compounds

Inhibitory effect of high phenol concentration in treating coal gasification wastewater in anaerobic biofilter

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Journal of environmental sciences 2018年第2期30卷 207-215页

作者： Yajie Li Salma Tabassum Chunfeng Chu Zhenjia Zhang School of Environmental Science and Engineering Suzhou University of Science and Technology School of Environmental Science and Engineering Shanghai Jiao Tong University

In this paper, the inhibition of methanogens by phenol in coal gasification wastewater(CGW)was investigated by both anaerobic toxicity tests and a lab-scale anaerobic biofilter reactor(AF). The anaerobic toxicity tests indicated that keeping the phenol concentration in the influent under 280 mg/L could maintain the methanogenic activity. In the AF treating CGW,the result showed that adding glucose solution as co-substrate could be beneficial for the quick start-up of the reactor. The effluent chemical oxygen demand(COD) and total phenol reached1200 and 100 mg/L, respectively, and the methane production rate was 175 m L CH4/g COD/day.However, if the concentration of phenol was increased, the inhibition of anaerobic micro-organisms was irreversible. The threshold of total phenol for AF operation was 200–250 mg/L. The extracellular polymeric substances(EPS) and particle size distribution of anaerobic granular sludge in the different stages were also examined, and the results indicated that the influence of toxicity in the system was more serious than its effect on flocculation of EPS. Moreover, the proportion of small size anaerobic granular sludge gradually increased from10.2% to 34.6%. The results of high through-put sequencing indicated that the abundance of the Chloroflexi and Planctomycetes was inhibited by the toxicity of the CGW, and some shifts in the microbial community were observed at different stages.

关键词：煤气化废水厌氧酚毒性测试实验室规模化学药品粒子尺寸反应堆

Component regulation in novel La-Co-O-C composite catalyst for boosted redox reactions and enhanced thermal stability in methane combustion

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Journal of environmental sciences 2023年第4期126卷 459-469页

作者： Peiqi Chu Saifei Wang Yi Zhang Shiguang Zhao Yahan Wang Jiguang Deng Erhong Duan School of Environmental Science and Engineering Hebei University of Science and TechnologyShijiazhuang 050018China school of Chemical and Pharmaceutical engineering Hebei University of Science and TechnologyShijiazhuang 050018China College of environmental and Energy engineering Beijing University of TechnologyBeijing 100124China

A novel La-Co-O-C (LC-C) composites were prepared via a facile co-hydrothermal route with oxides and glycerol and further optimized for methane catalytic activity and thermal stability via component regulation.It was demonstrated that Co3O_(4)phase was the main component in regulation.The combined results of X-ray photoelectron spectroscopy (XPS),temperature-programmed desorption of oxygen (O_(2)-TPD),temperature-programmed reduction of hydrogen (H_(2)-TPR),temperature-programmed desorption of ammonia/carbon dioxide (NH_(3)/CO_(2)-TPD) revealed that component regulation led to more oxygen vacancies and exposure of surface Co_(2)+,lower surface basicity and optimized acidity,which were beneficial for adsorption of active oxygen species and activation of methane molecules,resulting in the excellent catalytic oxidation performance.Especially,the (3.5)LC-C (3.5 is Co-to-La molar ratio) showed the optimum activity and the T50and T90(the temperature at which the CH_(4)conversion rate was 50%and 90%,respectively) were 318 and 367℃,respectively.Using theoretical calculations and in situ diffuse reflection infrared Fourier transform spectroscopy characterization,it was also found that the catalytic mechanism changes from the “Rideal-Eley” mechanism to the “Two-term” mechanism depending on the temperature windows in which the reaction takes place.Besides,the use of the “Flynn-Wall-Ozawa” model in thermoanalytical kinetics revealed that component regulation simultaneously optimized the decomposition activation energy,further expanding the application scope of carboncontaining composites.

关键词： Methane combustion Composite oxides Co3O_(4) Component regulation

Peroxymonosulfate activation based on Co_(9)S_(8)@N-C:A new strategy for highly efficient hydrogen production and synchronous formaldehyde removal in wastewater

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Journal of Materials science & Technology 2022年第32期127卷 256-267页

作者： Caiyan Gao Xuezhen Feng Lian Yi Xiaoyong Wu Renji Zheng Gaoke Zhang Yubiao Li school of Resources and environmental engineering Wuhan University of TechnologyWuhan 430070China School of Environmental Science and Engineering Southern University of Science and TechnologyShenzhen 518055China

Formaldehyde(FA),as an important chemical raw material,has been widely used in many fields.However,the discharge of a large amount of FA-containing wastewater poses a serious threat to the environment and human health.Recently,the in-situ hydrogen energy release technology of hydrogen-containing stable liquid has been extensively explored due to its safe storage.Exploring a robust method to achieve FA removal and synchronous in-situ hydrogen release from FA containing wastewater is of great significant for environmental protection and energy crisis alleviation.Here,we have innovatively introduced peroxymonosulfate(PMS)activation technology into FA removal and hydrogen production simultaneously.The composite of nitrogen doped carbon coating Co_(9)S_(8)nanotubes(Co_(9)S_(8)@N-C)is employed as a proof of concept for FA decomposition and simultaneously hydrogen production based on PMS activation system.As expected,the Co_(9)S_(8)@N-C/PMS system presents much superior hydrogen production efficiency and satisfactory FA removal rate towards FA wastewater than those of common catalysis,photocatalysis and Fenton reaction in the basic condition in a wide range of FA concentration.The hydrogen yield reaches a value as high as 471μmol within 60 min,corresponding to a FA degradation rate of 30%with an initial FA concentration of 0.722 mol L^(-1).Characterizations and density functional theory(DFT)calculations suggest that the free radical process dominated by superoxide radical(O_(2)·^(-))and nonradical process dominated by singlet oxygen(^(1)O_(2)),which are induced by Co_(9)S_(8)@N-C/PMS system,are responsible for highly efficient hydrogen production via FA degradation.These generated O_(2)·^(-)and ^(1)O_(2)can extract·H from FA to form·OOH intermediate,which can further combine with the·H from water to produce hydrogen.This study provides an applicable technique for environmental purification and new energy development based on FA containing wastewater.

关键词： Peroxymonosulfate activation Co9S8@N–C Hydrogen evolution Formaldehyde removal

Insights into the changes of amino acids,microbial community,and enzymatic activities related with the nutrient quality of product during the composting of food waste

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Frontiers of environmental science & engineering 2023年第3期17卷 93-105页

作者： Ying Xue Keke Xiao Xiang Wu Mei Sun Yifei Liu Bei Ou Jiakuan Yang School of Environmental Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China

This study systematically investigated the changes of amino acids as the composting process of food waste proceeded.It is found that the addition of 0.3 g/g total solids of food waste achieved the highest seed germination index of the product(268%).The microbial community results indicated that the abundance of amino acid metabolism sequences remained at high levels during the whole composting process.Proline was identified as the key amino acid related with the nutrient quality of product during the composting of food waste.Further plant germination and hydroponic experiments found,that compared with those without the addition of proline,the addition of 50 mg/L proline increased seed germination rate by 20%,increased shoot length by 3%,increased root biomass of seedlings by 82%,and increased leaf biomass of seedlings by 76%,respectively.Firmicutes,γ-Pseudomonadota,Chloroflexi and Planctomycetes were the key identified bacteria related with the increase of proline during the composting of food waste.Meanwhile,the enzymatic tests of the activities of superoxide dismutase,peroxidase and malondialdehyde indicated that proline did not cause oxidative damage on the growth of plants.This study provided novel insights into the changes of amino acids,microbial community,and enzymatic activities related with the nutrient quality of product during the composting of food waste.

关键词： Composting Food waste Amino acids Microbial community Enzymatic activity Nutrient quality

COF-based membranes for liquid phase separation:Preparation,mechanism and perspective

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Journal of environmental sciences 2024年第7期141卷 63-89页

作者： Yujie Zhao He Gu Yilun Zhou CaimeiWen Xiaolu Liu Suhua Wang Zhongshan Chen Hui Yang Xiangke Wang College of environmental science and engineering North China Electric Power UniversityBeijing 102206China School of Environmental Science and Engineering Guangdong University of Petrochemical TechnologyMaoming 525000China

Covalent organic frameworks(COFs)are a new kind of crystalline porous materials composed of organic molecules connected by covalent bonds,processes the characteristics of low density,large specific surface area,adjustable pore size and structure,and easy to functionalize,which have been widely used in the field of membrane separation technology.Recently,there are more and more researches focusing on the preparation methods,separation application,and mechanism of COF membranes,which need to be further summarized and compared.In this review,we primarily summarized several conventional preparation methods,such as two-phase interfacial polymerization,in-situ growth on substrate,unidirectional diffusion method,layer-by-layer assembly method,mixed matrix membranes,and so on.The advantages and disadvantages of each method are briefly summarized.The application potential of COF membrane in liquid separation are introduced from four aspects:dyeing wastewater treatment,heavy metal removal,seawater desalination and oil-water separation.Then,the mechanisms including pore structure,hydrophilic/hydrophobic,electrostatic repulsion/attraction and Donnan effect are introduced.For the efficient removal of different kind of pollutions,researchers can select different ligands to construct membranes with specific pore size,hydrophily,salt or organic rejection ability and functional group.The ideas for the design and preparation of COF membranes are introduced.Finally,the future direction and challenges of the next generation of COF membranes in the field of separation are prospected.

关键词： Covalent organic frameworks Membrane materials Liquid phase separation Separation mechanism

Adsorption, separation and recovery properties of blocky zeolite-biochar composites for remediation of cadmium contaminated soil

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Chinese Journal of Chemical engineering 2023年第2期54卷 272-279页

作者： Miaomiao Zhao Degang Ma Yu Ye School of Environmental Science and Engineering Tianjin UniversityTianjin 300350China

Cadmium(Cd) contamination in soils is a global ecological threat. Conventional powdered biochar added to soil can temporarily immobilize Cd but is difficult to separate from soil, leading to secondary release of Cd and posing potential ecological and human health risks. The blocky biochar is also difficult to separate from the soil due to its fragile nature. One of the keys to overcome the difficulties in separating biochar from soil is to improve its mechanical strength. Blocky zeolite-biochar composites(ZBC) that have good mechanical strength were obtained after pyrolyzing the mixture of 50% feedstock and 50% zeolite powder at 400 ℃. ZBC and NaOH-activated ZBC(ZBC_a) were applied to remove Cd from soil. After sieving Cd-loaded ZBC and ZBC_a from soil, the bioavailable Cd content in the soil decreased by 59.70% and 68.54%,respectively. Zeolite contributed to improving both adsorption performance and mechanical properties of the composites. After repeating the process of “remediation-sieving-desorption-regeneration” three times, the recoveries of ZBC and ZBC_a were above 97.00%, and regeneration rates were 48.70-83.26%,respectively. Under simulated mechanical sieving conditions, ZBC and ZBC_a lost only 4.06% and 5.40%of their mass and retained their integrity. Remediation of Cd-contaminated soil with blocky zeolitebiochar composite is sustainable and safe because the removal of bioavailable Cd from soil is permanent rather than a temporary decrease of bioavailability. This study provides a reference for the preparation of separable and recyclable adsorbents for the removal of contaminants from soil.

关键词： Zeolite-biochar composite Adsorption Separation Recycling Cd-contaminated soil

A novel online analyzer for accurate and rapid measurement of volatile fatty acids in anaerobic wastewater treatment

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Journal of environmental sciences 2022年第12期34卷 72-82页

作者： Qingshan Lin Yanchao Yuan Feixiang Zan Hui Lu Zongping Wang Gang Guo School of Environmental Science and Engineering Huazhong University of Science and Technology(HUST)Key Laboratory of Water and Wastewater TreatmentMOHURDWuhan 430074China Department of environmental science and engineering Beijing University of Chemical TechnologyBeijing 100029China School of Environmental Science and Engineering Sun Yat-sen UniversityGuangzhou 510275China

Volatile fatty acids(VFAs), which are largely generated during the anaerobic acidification process, are considered to be reliable indicators of the stable process operation. However,the common methods for monitoring VFAs are offline, and they are typically manual requiring time-consuming, costly and complex instruments. This study aims to develop a novel online analyzer for automatic measuring VFAs, which was based on the 5-p H point titration, embedded with a proportional-integral-derivative(PID) feedback control system. The results show that it can achieve accurate and rapid monitoring of VFAs ranging between 0-400 mg/L(<9 min/sample) but simultaneously faces the problems of overtitration and interference of complex characteristics of wastewater. In order to improve its accuracy and stability, the effects of three general coefficients(K_(I),K_(P), and K_(D)) of PID on the titration were investigated, and the optimal values of K_(I), K_(P), and K_(D)were found to be 1.5, 1.0, and-1.0~0.5,respectively. Besides, the initial titration speed was set at 0.06 m L/min, equal to the minimum speed of the peristaltic pump, and the dichotomy approach was integrated into the PID feedback controller. Owing to the above improvements, the relative mean deviation and standard deviation of measuring VFAs in both synthetic and real wastewaters were mostly lower than 5.0% and 5.0 mg/L, proving the online analyzer is rapid, accurate and reliable.

关键词： Volatile fatty acids Online analyzer 5-pH point titration PID feedback control Anaerobic process

金属相1T-MoS_(2)/ZnIn_(2)S_(4)异质结调控电荷传输从而促进光催化氧化还原反应

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science China Materials 2024年第2期67卷 532-540页

作者：张洪文姚雪山巍刘玥唐华 School of Environmental Science and Engineering Qingdao UniversityQingdao 266071China school of Materials science and engineering Jiangsu UniversityZhenjiang 212013China

近年来,光催化产氢与有机物氧化的偶联反应备受关注,如何设计高效双功能光催化剂实现偶联反应成为研究重点.在众多光催化剂中,ZnIn_(2)S_(4)以其优异的可见光吸收能力、本征的极化电场以及较强的氧化还原能力成为双功能催化剂的热点备... 详细信息

近年来,光催化产氢与有机物氧化的偶联反应备受关注,如何设计高效双功能光催化剂实现偶联反应成为研究重点.在众多光催化剂中,ZnIn_(2)S_(4)以其优异的可见光吸收能力、本征的极化电场以及较强的氧化还原能力成为双功能催化剂的热点备选材料.然而,电子空穴分离效率低以及光生电子空穴复合率高的问题限制了ZnIn_(2)S_(4)光电转化效率的进一步提高.针对这一问题,我们采用了具有较高导电性和独特结构的金属相1T-MoS_(2)作为助催化剂与花状ZnIn_(2)S_(4)复合形成“海胆状”的1T-MoS_(2)/ZnIn_(2)S_(4)欧姆结复合材料.理论计算结合XPS数据揭示了欧姆结与内建电场的形成,一系列光谱表征表明由欧姆结所形成的强内建电场促进了ZnIn_(2)S_(4)体内光生电子快速向1T-MoS_(2)转移,同时活性测试与EPR表征证明了苯甲醇的氧化反应可以作为光生空穴的有效捕获剂.最终,1T-MoS_(2)/ZnIn_(2)S_(4)复合光催化剂实现了4.6倍光催化性能的提高,420 nm波长下表光量子效率达6.75%.本项工作通过精确调节电荷转移机制,实现了ZnIn_(2)S_(4)双功能催化剂光电效率的进一步提高,为光催化剂载流子调控设计提供了新思路.

关键词： metallic 1T-MoS_(2) heterojunction photocatalyst photocatalytic hydrogen evolution benzyl alcohol oxidation guiding charge migration