期刊：
International Journal of Environmental Research and Public Health,2022年19(11):6529- ISSN：1661-7827
通讯作者：
Jie Zhang
作者机构：
[Zhang, Xiaoling; Wang, Liangqin; Li, Jie; Song, Xin; Zeng, Taotao; Yang, Jinhui; Chen, Shengbing] Univ South China, Hunan Prov Key Lab Pollut Control & Resources Reu, Hengyang 421001, Peoples R China.;[Zhang, Jie] Harbin Inst Technol, State Key Lab Urban Water Resources & Environm, Harbin 150090, Peoples R China.
通讯机构：
[Jie Zhang] S;State Key Laboratory of Urban Water Resources and Environment, Harbin Institute of Technology, Harbin 150090, China<&wdkj&>Author to whom correspondence should be addressed.
关键词：
heavy metals;wastewater treatment;industrial zones;microbial community;human health;water pollution
摘要：
Water pollution caused by heavy metals (HMs) poses a serious risk to human health and the environment and can increase the risk of diabetes, cancer, and hypertension in particular. In this study, two full-scale wastewater treatment plants (WWTPs) in industrial zones in southern China were selected to analyze the microbial community structure, diversity, similarity, and differentiation in the anoxic/oxic (AO) and anoxic/oxic membrane bioreactor (AO-MBR) units under the stress of HMs. High-throughput sequencing showed that microbial diversity and abundance were higher in the AO process than in the AO-MBR process. In the two WWTPs, the common dominant phyla were Proteobacteria and Bacteroidetes, while the common dominant genera were Gemmatimonadaceae, Anaerolineaceae, Saprospiraceae, and Terrimonas. Manganese (Mn) and zinc (Zn) positively correlated with Saccharimonadales, Nakamurella, Micrococcales, and Microtrichales, whereas copper (Cu) and iron (Fe) positively correlated with Longilinea and Ferruginibacter. Additionally, the relative abundances of Chloroflexi, Patescibacteria, and Firmicutes differed significantly (p < 0.05) between the two processes. These results may provide comprehensive outlooks on the characterization of microbial communities in WWTPs, which could also help to reduce the potential environmental risks of the effluent from WWTPs located in industrial zones.
作者机构：
[Yang, Shijiao; Fan, Junwei] Univ South China, Sch Resource Environm & Safety Engn, Hengyang 421001, Peoples R China.;[Deng, Bo; Fan, Junwei; Sun, Bing] Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China.;[Liu, Taoying] Cent South Univ, Sch Resources & Safety Engn, Changsha 410012, Peoples R China.
通讯机构：
[Bo Deng] S;School of Civil Engineering, University of South China, Hengyang 421001, China<&wdkj&>Author to whom correspondence should be addressed.
摘要：
In consideration of the temporary stability of the cutting slope during construction and its permanent stability under long-term service, a new technique of lattice beam construction with anchors pre-set in the slope from the original ground surface before cutting was proposed, and its construction process was briefly introduced. Compared with the model without pre-set anchors, the effectiveness of pre-setting anchors to strengthen the cutting slope during multi-excavation was verified in the numerical software FLAC(3D). Various factors such as the factor of safety (FOS) and the maximum shear strain increment (MSSI) as well as the displacement for different stages were discussed. The results show that the anchors pre-set in the slope provide reinforcement step-by-step with excavations which changes the mechanical responses of the cutting slope and increases the factor of safety with a variation of 15.9-44.1% compared to the case without setting anchors. In addition, with excavations, the axial forces of the anchors pre-set in the stratum increase gradually, and the positions of the maximum axial forces gradually transfer from the vicinity of the cutting surface to the depth of the design slope. Numerical simulations prove that this new technique is beneficial for ensuring the temporary stability of the slope during excavations and is especially suitable for the advance anchorage of the cutting slope, in which the inclined original ground surface is cut at an angle steeper than it can stand safely and is close to the design slope surface after cutting. After the completion of slope excavation, the cast-in-place concrete lattice beam is immediately set on the design slope surface and connected with the anchor heads exposed on the cut slope surface to ensure the permanent stability of the slope. Therefore, this new technology has important guiding significance for both the temporary stability of slopes during construction and the permanent stability of slopes in service.
通讯机构：
[Liu, Jinxiang] H;Hunan Provincial Key Laboratory of Pollution Control and Resources Technology, University of South China, Hengyang, 421001, China.;Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang, 421001, China.
摘要：
Perennial ryegrass (Lolium perenne L.) was planted in uranium-contaminated soil mixtures supplemented with different amounts of citric acid to investigate the defense strategies of perennial ryegrass against U and the enhanced mechanism of citric acid on the remediation efficiency in the laboratory. The uranium content in the plant tissues showed that the roots were the predominant tissue for uranium accumulation. In both root and shoot cells, the majority of U was located in the cell wall fraction. Furthermore, antioxidant enzymes were also stimulated when exposed to U stress. These results suggested that perennial ryegrass had evolved defense strategies, such as U sequestration in root tissue, compartmentalization in the cell wall, and antioxidant enzyme systems, to minimize uranium stress. For an enhanced mechanism, the optimal concentration of citric acid was 5 mmol/kg, and the removal efficiency of U in the shoots and roots increased by 47.37% and 30.10%, respectively. The treatment with 5 mmol/kg citric acid had the highest contents of photosynthetic pigment and soluble protein, the highest activity of antioxidant enzymes, and the lowest content of MDA (malondialdehyde) and relative electrical conductivity. Moreover, the TEM (transmission electron microscope) results revealed that after 5 mmol/kg citric acid was added, the cell structure of plant branches partially returned to normal, the number of mitochondria increased, chloroplast surfaces seemed normal, and the cell wall became visible. The damage to the cell ultrastructure of perennial ryegrass was significantly alleviated by treatment with 5 mmol/kg citric acid. All the results above indicated that perennial ryegrass could accumulate uranium with elevated uranium tolerance and enrichment ability with 5 mmol/kg citric acid.
通讯机构：
School of Civil Engineering, Shaoxing University, Shaoxing, China
摘要：
Among the factors affecting rock mass failure, the stress state has the greatest influence on the mechanical behavior of rock. The mechanical behavior of rock depends on the change of stress path, and the stress of rock mass is closely related to deformation and failure. In order to study the influence of surrounding rock stress state on the failure mode of surrounding rock, based on the theory of elastic mechanics and fracture mechanics, this paper analyzed the stress state of surrounding rock element and crack propagation of surrounding rock, and estimated the potential failure mode of surrounding rock in different areas of a phosphate mine in Yichang. The results showed that: the surrounding rock element is affected by the gradient stress, and a larger stress gradient corresponds to a larger principal stress ratio and variation direction of the surrounding rock. The failure mode of surrounding rock is affected by the coupling effect of principal stress ratio and principal stress direction. Under the action of certain crack angle and appropriate confining pressure, different fracture mechanisms may occur in the surrounding rock compression. But the partition of surrounding rock failure mode region can predict the surrounding rock failure mode to a certain extent.
期刊：
International Journal of Heat and Mass Transfer,2021年173:121240 ISSN：0017-9310
通讯作者：
Hao Liu
作者机构：
[Liu, Hao; Qiu, Zhouhua] Chongqing Jiaotong Univ, Chongqing Southwest Res Inst Water Transport Engn, Chongqing 400016, Peoples R China.;[Liu, Hao; Qiu, Zhouhua] Chongqing Jiaotong Univ, Key Lab Inland Waterway Regulat Engn, Minist Commun, Chongqing 400074, Peoples R China.;[Liu, Hao; Qiu, Zhouhua] Chongqing Xike Consulting Ctr Water Transport Eng, Chongqing 400016, Peoples R China.;[Zeng, Zhong] Chongqing Univ, Coll Aerosp Engn, Chongqing 400044, Peoples R China.;[Yin, Linmao] Univ South China, Sch Civil Engn, Hengyang 421001, Hunan, Peoples R China.
通讯机构：
[Hao Liu] C;Chongqing Southwest Research Institute for Water Transport Engineering, Chongqing Jiaotong University, Chongqing 400016, China<&wdkj&>Key Laboratory of Inland Waterway Regulation Engineering Ministry of Communications, Chongqing Jiaotong University, Chongqing 400074, China<&wdkj&>Chongqing Xike Consulting Center for Water Transport Engineering, Chongqing 400016, China
摘要：
In this paper, the onset of Rayleigh-Benard convection of cold water near its density maximum in a vertical cylindrical container and the stability of the steady axisymmetric flow were studied by using linear stability analysis. The results show that the critical Rayleigh number for the onset of convection increases with increasing the density inversion parameter Tm (Tm=(Phi(max)-Phi(c))/(Phi(h)-Phi(c)), where Phi(max) is the temperature at the maximum density, and Phi(h) and Phi(c) are the temperature at the bottom wall and top wall, respectively), and some new flow patterns not found in the Rayleigh-Benard convection of common fluids are presented. Within a certain range of density inversion parameters, the onset of convection is steady and axisymmetric. The steady axisymmetric basic flow is found to depend on the initial condition, and two distinctly different basic flow are obtained at identical parameters, due to the top-bottom symmetry breaking. For the upward basic flow, four different flow patterns are observed after the axisymmetry-breaking instability. In addition, a hysteresis phenomenon of the flow pattern transition is found when Tm=0.57. For the downward basic flow, six flow patterns are observed after the axisymmetry-breaking instability. In particular, it is found that there still exists stable axisymmetric flow beyond the second bifurcation in certain ranges of Rayleigh numbers. The energy analysis shows that both the primary instability and the axisymmetry-breaking instability are caused by the thermal-buoyancy mechanism. (C) 2021 Elsevier Ltd. All rights reserved.
关键词：
Exergy;Solid waste;Gasification;Updraft;Downdraft;Fixed bed
摘要：
The most commonly used for gasification of village-level solid waste is the fixed-bed gasifier, but there is no reasonable method to evaluate the gasification process. This paper attempts to find a gasifier that is most suitable for gasification of village-level solid wastes through exergy analysis method. Based on experimental data from literature, the exergy efficiencies and LHV(Low Heat Value) of product gas from updraft and downdraft fixed bed gasifier are studied in this paper. The results show that the updraft fixed bed gasifier has higher exergy efficiency, and the gas produced by the downdraft fixed bed gasifier has a higher heating value. Air gasification has higher exergy efficiency than steam gasification and pure oxygen gasification. The highest exergy efficiency at a gasification temperature of about 1000 degrees C and ER (Equivalence Ratio) value in the range of 0.33-0.36. The volatile content of gasification raw materials is higher, and the gasification efficiency is higher. Through the research of this paper, a new path to reasonably evaluate the gasification process is obtained. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
通讯机构：
[Shukui Zhou] S;School of Civil Engineering, University of South China, Hunan, People’s Republic of China
关键词：
Nanoscale hydroxyapatite (nHAP);Nanoscale hydroxyapatite;Nanoscale zerovalent iron mixture (nHAP NZVI);Uranium;Immobilize
摘要：
One of the more concerning issues in the world today is that radioactive uranium contaminates the soil and threatens the organisms. The focus of contaminated soil remediation is to immobilize the uranium in the soil and reduce its leaching. Nano-hydroxyapatite (nHAP) and nano-hydroxyapatite/nano-zero-valent iron mixture (nHAP/nZVI) are used as immobilizer to remediate uranium-contaminated soil. The leaching characteristics and morphological changes of uranium before and after immobilization were studied by using Toxicity Characteristic Leaching Procedure (TCLP) and Tessier stepwise chemical extraction method. The results show that the leaching concentration of uranium in the soil was 0.005 mg/L when nHAP was added alone, and the leaching rate was 9.14%. The leaching concentration of uranium in the soil was only 0.004 mg/L when adding nHAP/nZVI, and the leaching rate was reduced to 8.57%. U (VI) not only reacts with nHAP to form a stable complex but also is reduced by nZVI to insoluble U (IV) when nHAP/nZVI is added. As a result, both nHAP/nZVI and nHAP can effectively immobilize uranium in the soil, and nHAP/nZVI can better promote the immobilization of the uranium in the soil.
期刊：
Journal of Radioanalytical and Nuclear Chemistry,2021年328(1):39-47 ISSN：0236-5731
通讯作者：
Xie, Dong
作者机构：
[Wang, Chenhua; Xie, Dong] Natl & Local Joint Engn Res Ctr Airborne Pollutan, Hengyang 421001, Peoples R China.;[Wang, Chenhua; Xie, Dong; Wang, Hanqing; Yu, Chuck Wah; Yang, Xiaomin] Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China.;[Wang, Hanqing] Cent South Univ Forestry & Technol, Sch Civil Engn, Changsha 410211, Peoples R China.
通讯机构：
[Xie, Dong] N;[Xie, Dong] U;Natl & Local Joint Engn Res Ctr Airborne Pollutan, Hengyang 421001, Peoples R China.;Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China.
关键词：
Rn-222 exhalation;Temperature difference;Water content;Concrete block;Grey prediction model
摘要：
Effects of temperature difference between indoor air and concrete, and water content in concrete, on Rn-222 exhalation were investigated. In concrete with 0% water content, the heat generated due to temperature difference between concrete and indoor air could raise Rn-222 exhalation rate by 2.6 times. The Rn-222 exhalation rate rose initially, then declined as water content in concrete was increased. The maximum Rn-222 exhalation rate was 4.4 mBq m(-1) s(-1) in concrete with 10% water content. A grey prediction model was established for predicting Rn-222 exhalation rates and exposure doses of residents due to different indoor temperature differences with concrete.
摘要：
The effects of calcium content on the molecular structure and mechanical properties of sodium aluminosilicate hydrate (NASH) gels were studied by molecular dynamics simulations. NASH gels with different calcium content were constructed, followed by optimization, equilibration, and production runs of molecular dynamics simulation. Properties such as energy profile, radial distribution function (RDF), distribution of bond length and bond angle, mean square displacement (MSD), elastic modulus and density were obtained. The results indicated that with the increase of Ca/Al, average bond lengths and total energy decreased monotonically, and the distributions of bond lengths and bond angles became narrower. Results from the MSD analysis showed that diffusion degree of both Si and Al in the gels decreased with the increase of the Ca/Al ratio. Furthermore, the elastic modulus, compressive strength and density of the gel systems increased monotonically with the increase of calcium content, and the trend is consistent with experimental findings.
摘要：
The rheokinetics of geopolymer slurry and its fluidity modification methods, as well as modification mechanism were investigated by performing viscosity time dependence experiments and a cement comparative experiment. The results show that the viscosity curve of geopolymer slurry fits well with power law equations. The viscosity time dependence can be employed to characterize the geopolymerization process, and to describe the variations of fluidity with time. K+ activated geopolymer has lower initial viscosity and better fluidity retention than Na+ does. Among superplasticizers, naphthalene-based superplasticizer performs best, but superplasticizers simultaneously promote the deformation of viscosity. Viscosity curve of cement changed unevenly. (C) 2020 Elsevier Ltd. All rights reserved.
作者：
Ouyang, Gaoshang;Wu, Lianjie;Ye, Chuxiong;Wang, Jingsong;Dong, Teng
期刊：
Construction and Building Materials,2021年290:123223 ISSN：0950-0618
通讯作者：
Wang, Jingsong(1994000105@usc.edu.cn)
作者机构：
[Ouyang, Gaoshang; Ye, Chuxiong; Wang, Jingsong; Dong, Teng; Wu, Lianjie] Univ South China, Sch Civil Engn, Hengyang 421001, Hunan, Peoples R China.;[Ouyang, Gaoshang; Wang, Jingsong; Wu, Lianjie] Univ South China, Yangtze Delta Res Inst, Zhuji 311800, Zhejiang, Peoples R China.
通讯机构：
[Jingsong Wang] S;School of Civil Engineering, University of South China, Hengyang 421001, Hunan Province, China<&wdkj&>Yangtze Delta Research Institute, University of South China, Zhuji 311800, Zhejiang Province, China
摘要：
Y Fluidity modification on geopolymer without changing its compositions is necessary. This study, firstly, investigated the optimal oxides molar ratios of geopolymers, then rheology, rheokinetics, fluidity and mechanical properties tests were conducted to study the influence of silane coupling agent (SCA) on geopolymers. Finally, characterization techniques of SEM, pore size distribution, FTIR and DSC were used to reveal the mechanisms. The results show when SiO2/Al2O3 = 3.4, M2O/Al2O3 = 1, and H2O/M2O = 11, geopolymer's fluidity reaches 144 mm with the best compressive strength. The addition of 2 wt% SCA can reduce viscosity, increasing the fluidity to 167 mm, while excessive SCA can't. SCA can also increase the viscosity growth rate and influence the microstructure of geopolymers. (C) 2021 Elsevier Ltd. All rights reserved.
期刊：
Journal of Radioanalytical and Nuclear Chemistry,2021年329(2):815-827 ISSN：0236-5731
通讯作者：
Guohua Wang
作者机构：
[Zhang, Kao; Wu, Suiyi; Rong, Lishan; Li, Shiyou; Zeng, Taotao; Wang, Guohua] Univ South China, Hunan Prov Key Lab Pollut Control & Resources Tec, Hengyang 421001, Peoples R China.
通讯机构：
[Guohua Wang] H;Hunan Provincial Key Laboratory of Pollution Control and Resources Technology, University of South China, Hengyang, People’s Republic of China
摘要：
Polyethyleneimine (PEI) modified magnetic yeast biomaterials composites (MY@SiO2-PEI) were prepared through a two-step solution polymerization method to remove U(VI) from aqueous solutions. The impact of six anions on U(VI) removal efficiency with MY@SiO2-PEI in single- and multi-ion systems was conducted in this article. A 26–2 Fractional factorial design (FFD) and Visual MINTEQ were employed to identify primary or interacting factors and the uranium chemical speciation calculations, respectively. In the single-ion systems, PO43−, humic acids (HA) slightly increased the U(VI) removal efficiency with MY@SiO2-PEI at low pH, whereas the U(VI) removal efficiency was largely reduced with SO42−, CO32−. The factorial effects of the six selected species on U(VI) removal efficiency via FFD in the multi-ion system were in the following sequence: CO32− > Cl− > HA > PO43− > SO42− > NO3−, and U(VI) removal was affected significantly by the combined of AB (Cl− × NO3−), BD (NO3− × SO42−).
通讯机构：
[Zeng, Sheng] S;School of Resource & Environment and Safety Engineering, University of South China, Hengyang, 421001, Hunan, China.;ARC Centre of Excellence for Geotechnical Science and Engineering, The University of Newcastle, Callaghan, NSW, 2308, Australia.
摘要：
To investigate the influence of the fissure morphology on the dynamic mechanical properties of the rock and the crack propagation, a drop hammer impact test device was used to conduct impact failure tests on sandstones with different fissure numbers and fissure dips, simultaneously recorded the crack growth after each impact. The box fractal dimension is used to quantitatively analyze the dynamic change in the sandstone cracks and a fractal model of crack growth over time is established based on fractal theory. The results demonstrate that under impact test conditions of the same mass and different heights, the energy absorbed by sandstone accounts for about 26.7% of the gravitational potential energy. But at the same height and different mass, the energy absorbed by the sandstone accounts for about 68.6% of the total energy. As the fissure dip increases and the number of fissures increases, the dynamic peak stress and dynamic elastic modulus of the fractured sandstone gradually decrease. The fractal dimensions of crack evolution tend to increase with time as a whole and assume as a parabolic. Except for one fissure, 60° and 90° specimens, with the extension of time, the increase rate of fractal dimension is decreasing correspondingly.
关键词：
Sulfur-containing tailings sand;Immersion test;Oxidation and acidification;Physical and mechanical properties;Numerical simulation
摘要：
For studying the mechanical properties of sulfur-containing tailings material in the acidification environment, the tailings material was soaked in H2O2 solution with different concentrations to simulate the oxidation and acidification of the tailings with different accumulation history. The change laws and mechanisms of its mechanical properties after oxidation and acidification were discussed, and through the PFC (particle flow code) mesoscopic discrete element analysis method, the connection between mesoscopic particles and its macroscopic properties was established. The experimental results show that the chemical immersion tests on tailings materials with a certain ratio of hydrogen peroxide to concentrated sulfuric acid can well simulate the joint action of oxidation and acidification, so as to simulate the tailings with different accumulation history. Under the action of oxidation and acidification, the physical and mechanical properties of tailings material are mainly affected by the particle size and contact characteristics. The angle of internal friction decreases, influenced by the reduction of particle size, while the change of cohesive force is greatly correlated with both of the two factors. The shear modulus under different porosity and friction coefficients is basically the same, but the increase of porosity or the decrease of mesoscopic particle friction coefficient will greatly weaken its shear capacity, that is, its mesoscopic particle compactness and contact characteristics have an important impact on the macroscopic mechanical properties of tailings.
期刊：
Journal of Environmental Chemical Engineering,2021年9(6):106363 ISSN：2213-3437
通讯作者：
Duan, Yi;Tang, Zhenping
作者机构：
[Zhou, Shuai; Duan, Yi; Liu, Yingjiu] Univ South China, Hunan Prov Key Lab Pollut Control & Resources Reu, Hengyang 421001, Peoples R China.;[Zhou, Shuai; Duan, Yi; Liu, Yingjiu; Xie, Yanxing] Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China.;[Gao, Yuanyuan; Zhu, Feiyu; Tang, Zhenping] Univ South China, Hunan Prov Key Lab Rare Met Minerals Exploitat &, Hengyang 421001, Peoples R China.
通讯机构：
[Duan, Yi; Tang, Zhenping] U;Univ South China, Hunan Prov Key Lab Pollut Control & Resources Reu, Hengyang 421001, Peoples R China.;Univ South China, Hunan Prov Key Lab Rare Met Minerals Exploitat &, Hengyang 421001, Peoples R China.
关键词：
U(VI);Adsorption;PAO/GO/CS;Density functional theory
摘要：
Graphene oxide (GO) and its composites are promising candidates for the adsorption of U(VI) in water. Whereas the high hydrophobicity and dispersibility of GO makes it hard to separate from aqueous solutions, and thus greatly restricts its practical application. To address this defect, a novel composite [i.e., poly(amidoxime)/GO/chitosan (PAO/GO/CS)] was prepared. Characterization including Fourier transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy confirmed that cross-linking reaction between GO and CS may consume oxygen-contained groups of GO. The resulting deficit in U(VI) adsorption may be compensated by the amidoxime grafted onto the surface of GO/CS. Langmuir model showed that the maximum adsorption capacity of U(VI) by PAO/GO/CS was up to 701.5, 821.7, and 1220.0 mg/g, respectively, under 293, 303, and 313 K at pH 6.0. U(VI) is spontaneously and mainly chemically adsorbed onto the oxygen-containing groups (i.e., hydroxyl and amidoxime) in PAO/GO/CS based on characterization and density functional theory (DFT). DFT analysis indicated that the optimized adsorption energy of most stable configuration of the uranyl-PAO/GO/CS is -309.99 kcal/mol. PAO/GO/CS can achieve selective adsorption for U(VI) against common coexisting ions and superior separation from water. These findings demonstrate the feasibility of PAO/GO/CS composite used for the remediation of uranium-containing wastewater.
期刊：
Bulletin of Environmental Contamination and Toxicology,2021年107(6):1208-1219 ISSN：0007-4861
通讯作者：
Zeng, Taotao;Wang, Aijie
作者机构：
[Zhang, Xiaoling; Wang, Aijie; Zeng, Taotao; Nong, Haidu; Hu, Qing] Univ South China, Hunan Prov Key Lab Pollut Control & Resources Reu, Hengyang 421001, Peoples R China.;[Wang, Aijie] Chinese Acad Sci, Key Lab Environm Biotechnol, Beijing 100085, Peoples R China.
通讯机构：
[Taotao Zeng; Aijie Wang] H;Hunan Province Key Laboratory of Pollution Control and Resources Reuse Technology, University of South China, Hengyang, 421001, China.;Key Laboratory of Environmental Biotechnology, Chinese Academy of Sciences, Beijing, 100085, China.
关键词：
Selenium;Limited carbon;Acidic wastewater;Cadmium;Microbial community
摘要：
This study presents a successful treatment of biological acidic Se(IV)- and Cd(II)-containing wastewater via the SBR with limited carbon source (100 mg/L COD). Scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDS), high solution transmission electron microscopy (HRTEM) and X-ray photoelectron spectrometer (XPS) results verified the formation of elemental Se and CdSe nanoparticles in the sludge. The abundance of genera in the microbial community gradually changed over the treatment phases depending on the Se(IV) and Cd(II) exposure with different influent COD concentrations. The taxa of Proteiniclasticum, Clostridium_sensu_stricto_12, Longilinea and Mycobacterium were dominant. Redundancy analysis (RDA) indicates that COD concentrations had the greatest impact on Zoogloea and Pseudomonas by promoting an increased abundance and decreased abundance, respectively. Overall, the results extended our understanding of the mechanisms and microbial community responding for the Se(IV) and Cd(II) removal under limited carbon availability in acidic wastewater.
作者机构：
[Liu, Yuelin] Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Peoples R China.;[Liu, Yuelin] Hunan Univ Technol, Sch Civil Engn, Zhuzhou 412007, Peoples R China.;[Wu, Shanshan; Xie, Shuibo; Liu, Yingjiu] Univ South China, Hunan Prov Key Lab Pollut Control & Resources Reu, Hengyang 421001, Peoples R China.;[Liu, Jun] Hunan Univ Technol, Sch Life Sci & Chem, Hunan Key Lab Biomed Nanomat & Devices, Zhuzhou 412007, Peoples R China.;[Xie, Shuibo] Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China.
通讯机构：
[Xie, Shuibo] U;Univ South China, Hunan Prov Key Lab Pollut Control & Resources Reu, Hengyang 421001, Peoples R China.;Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China.
摘要：
Photocatalytic technology is a valid solution for the remediation of wastewater containing uranium. In this study, the synthesis of Z-scheme g-C3N4/TiO2 catalysts was made by a thermal synthetic approach for photocatalytic U(VI) reduction. The characterization results revealed the successful synthesis of g-C3N4/TiO2 nanostructures. The g-C3N4 surface was uniformly coated with TiO2 nanoparticles. The depletion of U(VI) in water evaluated the photocatalytic activity of g-C3N4/TiO2 under UV light irradiation. The photocatalytic tests showed that g-C3N4/TiO2 exhibited more effective photocatalytic activity than the raw materials (1.64 and 56.97 times higher than TiO2(P25) and g-C3N4, respectively). Besides, a pseudo-first-order model was followed by the experimental kinetic data for the photocatalytic process. Moreover, g-C3N4/TiO2 still presented high photocatalytic activity after four reacting cycles. Based on these experiment results, the improved photocatalytic activity could be attributed to the Z-scheme mechanism, which decreased the recombination of photo-produced electrons and holes. The synthesis of these g-C3N4/TiO2 nanomaterials provides a facile and inexpensive method for treating wastewater containing U(VI).
