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Bao Q.,Tsinghua University | Chen L.,Tsinghua University | Chen L.,Zhejiang Provincial Key Laboratory of Water Science and Technology | Tian J.,Tsinghua University | Wang J.,Tsinghua University
Radiation Physics and Chemistry | Year: 2014

Industrial wastewaters containing 2-mercaptobenzothiazole (MBT), a widely used chemical additive, usually cannot be treated properly by conventional biological methods, thus cause an environmental risk. Ionizing radiation was proposed as a method for abatement of several refractory pollutants from water. The paper investigated MBT degradation using irradiation technology. The decomposition kinetics was described, and the transformation and the change of biodegradability were discussed. The results of gamma radiation experiments on MBT-containing aqueous solutions indicated that reactive radicals resulting from water radiolysis effectively degrade MBT and improve the biodegradability of the solutions. At a 20. mg/L MBT concentration, the removal of 82% was achieved at the absorbed dose of 1.2. kGy. The results of specific oxygen uptake rate (SOUR) test showed that MBT was decomposed into biodegradable products, after irradiation at 20. kGy. Radicals attacked the sulfur atoms of the studied molecule leading to the release of sulfate ions, but the mineralization of organic carbons was rather weak. Initial concentration significantly affected the degradation efficacy of MBT by gamma radiation. © 2014 Elsevier Ltd.


Bao Q.,Jilin University | Chen L.,Tsinghua University | Chen L.,Zhejiang Provincial Key Laboratory of Water Science and Technology | Tian J.,Tsinghua University | Wang J.,Tsinghua University
Journal of Environmental Sciences (China) | Year: 2016

Recently, water treatment by ionizing radiation has gained increasing attention as a powerful technology for the destruction of refractory pollutants. 2-Mercaptobenzothiazole (MBT) is known as a widespread, toxic and poorly biodegradable pollutant. This paper studied the gamma irradiation of aqueous solutions of MBT. Moreover, the effect of the addition of persulfate (S2O8 2-) on the radiolytic destruction of MBT was investigated. The main transformation products of the studied compound were detected and the sequence of occurrence of the products was described. The change of biodegradability of MBT solution was also observed. The main results obtained in this study indicated that gamma radiation was effective for removing MBT in aqueous solution. Persulfate addition, which induced the formation of reactive sulfate radicals (SO4 - ), greatly enhanced the degradation of MBT. Benzothiazole was identified as the first radiation product, followed by 2-hydroxybenzothiazole. Decomposition of MBT started with the oxidation of -SH groups to sulfate ions. Possible pathways for MBT decomposition by gamma irradiation were proposed. The BOD/COD ratios of MBT samples were increased after radiation, indicating the improvement of biodegradability and reduction of toxicity. © 2016.


Liu W.,Tsinghua University | Sang J.,Tsinghua University | Sang J.,Energy Foundation China | Chen L.,Tsinghua University | And 5 more authors.
Journal of Cleaner Production | Year: 2015

Electric bikes (e-bikes) have developed faster than any other mode of transport in China, which has stimulated the rapid growth of China's lead-acid battery (LAB) industry for more than a decade. This research undertook a life cycle assessment (LCA) for LABs used in e-bikes in China. Its purpose was to identify the key materials and processes that contribute most to impacts on the environment and public health within the life cycle of LABs, from materials extraction and processing, manufacture, transportation, use, and end-of-life. It also sought to find opportunities for improving the environmental profile of LABs. The results indicate that LABs use, as well as materials extraction and processing, have the largest environmental impacts within the life cycle of LABs. The former is responsible for 84% of the primary energy use and contributes the highest potentials to energy-related impacts, including global warming (86%) and acidification (69%). The latter, specifically the lead used in batteries, is the most important driver of impacts such as ozone depletion, photochemical smog, eutrophication, and carcinogenicity. Accordingly, battery reuse after refurbishment and recovery of materials in the end-of-life stage could significantly mitigate most of the overall life cycle impacts by reducing the consumption of virgin materials. However, currently, 95% of total lead emissions are released in the end-of-life stage due to improper management of the spent LABs recycling market in China, and these emissions causes 90% of total human toxicity potential. Battery manufacture only accounts for 3% of total lead emissions after the national cleanup action for heavy metal pollution. Moreover, sensitivity coefficients are employed to evaluate the reliability and uncertainty of the LCA results. Based on the findings, there are several substantial opportunities to further reduce the overall environmental impacts of LABs, such as prolonging the lifetime of LABs, reducing the consumption of metals in LABs, and improving the technology and management in the recovery of spent LABs. © 2015 Elsevier Ltd.


Xie Y.,Tsinghua University | Chen L.,Tsinghua University | Chen L.,Zhejiang Provincial Key Laboratory of Water Science and Technology | Liu R.,Zhejiang Provincial Key Laboratory of Water Science and Technology
Journal of Environmental Sciences (China) | Year: 2016

Adsorbable organic halogens (AOX) are a general indicator for the total amount of compounds containing organically bonded halogens. AOX concentrations and components were investigated along the wastewater treatment process in four large-scale pharmaceutical factories of China, and genotoxicity based on the SOS/umu test was also evaluated. The results showed that AOX concentrations in wastewater of four factories ranged from 4.6 to 619.4. mg/L, which were high but greatly different owing to differences in the raw materials and products. The wastewater treatment process removed 50.0%-89.9% of AOX, leaving 1.3-302.5. mg/L AOX in the effluents. Genotoxicity levels ranged between 2.1 and 68.0. μg 4-NQO/L in the raw wastewater and decreased to 1.2-41.2. μg 4-NQO/L in the effluents of the wastewater treatment plants (WWTPs). One of the main products of factory I, ciprofloxacin, was identified as the predominant contributor to its genotoxicity. However, for the other three factories, no significant relationship was observed between genotoxicity and detected AOX compounds. © 2016.


Qi B.,Tsinghua University | Chen L.,Tsinghua University | Chen L.,Zhejiang Provincial Key Laboratory of Water Science and Technology | Wang J.,Tsinghua University
Chinese Journal of Environmental Engineering | Year: 2014

To determine the composition of organic pollutants in the cephalosporin synthesis wastewater, the gas chromatography-mass spectrometry (GC-MS) technology was used and the analytical method was optimized. The influent and effluent of the existing treatment system were sampled at a cephalosporin intermediate plant located in Tianjin. The organic matter was extracted from raw wastewater using dichloromethane. After concentration and purification, the samples were injected into the column for separation. The qualitative analysis was made by comparing the obtained mass spectrograms to NIST08 database. Over 30 kinds of organic pollutants were identified and the chemical structure and abundance information of each molecule were provided. After further classification of the listed components, it is concluded that heterocycles and nitrogen-containing polycycles are the most recalcitrant pollutants discharged by the cephalosporin intermediate plant which are supposed to be treated by additional physico-chemical process. ©, 2014, Science Press. All right reserved.


Xie Y.,Tsinghua University | Chen L.,Tsinghua University | Chen L.,Zhejiang Provincial Key Laboratory of Water Science and Technology | Liu R.,Zhejiang Provincial Key Laboratory of Water Science and Technology
Chemosphere | Year: 2016

Adsorbable organic halogens (AOX) and total organic carbon (TOC) removal efficiencies in pharmaceutical wastewater treated by Fenton process under response surface methodology (RSM) optimized conditions were studied. High regression coefficient value R2 (R2 = 0.9680, 0.9040 for AOX and TOC removal efficiency, respectively) and low value coefficient of variation (2.21%, 2.04% for AOX and TOC, respectively) of the quadratic model indicated that the model was accurate in predicting the experimental results. The desirability function was used to optimize AOX and TOC removal efficiencies simultaneously. The optimal pH, Fe2+ concentration, molar ratio of H2O2/Fe2+ and reaction time were found to be 3.3, 19.05 mM, 20.16 and 2.2 h, respectively, and 91.78% AOX and 75.01% TOC were removed under these conditions, which was validated. Furthermore, gas chromatography-mass spectrometer (GC-MS) results revealed that 28 out of 33 kinds of organic compounds, including 11 kinds of AOX were completely removed by the Fenton process while one new AOX compound, 4,5,6,7-tetrachlorophthalide, was produced which was the result of the carbonyl of 4,5,6,7-tetrachloro-1,3-isobenzofurandione being attacked in the Fenton reaction. These results indicated that analysis of organics was important since new AOX compounds could be produced in Fenton process despite the value of AOX decreasing. © 2016 Elsevier Ltd.


Zhu X.,Tsinghua University | Chen L.,Tsinghua University | Chen L.,Zhejiang Provincial Key Laboratory of Water Science and Technology | Liu R.,Zhejiang Provincial Key Laboratory of Water Science and Technology | And 2 more authors.
Environmental Sciences: Processes and Impacts | Year: 2013

The potential biotoxicity to the environment should be addressed during wastewater treatment. In this study, biotoxicity of coking wastewater effluent from MBR, Fenton, electro-Fenton and coagulation treatment processes was evaluated using embryos and larvae of Japanese medaka (Oryzias latipes). The acute toxicity based on 96-h larval mortality as well as the chronic toxicity based on embryo hatching, larvae swim-up failure, growth, and sexual ratio were determined. The results showed that different treatment processes have various biotoxicity levels. The acute toxicity of Fenton and electro-Fenton effluents was much higher than that of MBR and coagulation. For the chronic toxicity, the effluent of the Fenton/electro-Fenton process displayed lower embryo hatching, larvae survival and growth in comparison with the effluents of MBR and coagulation. No endocrine disruption was detected in MBR, Fenton and electro-Fenton effluents, but was contained in the coagulation effluent. The biotoxicity test indicated that the effluent of MBR was very safe for the environment. The toxicological indices were necessary for ecological safety maintenance in the industrial wastewater treatment. © 2013 The Royal Society of Chemistry.


Ma D.,Tsinghua University | Chen L.,Tsinghua University | Chen L.,Zhejiang Provincial Key Laboratory of Water Science and Technology | Zhu X.,Tsinghua University | And 3 more authors.
Environmental Science and Pollution Research | Year: 2014

To date, toxicological studies of endocrine disrupting chemicals (EDCs) have typically focused on single chemical exposures and associated effects. However, exposure to EDCs mixtures in the environment is common. Antiandrogens represent a group of EDCs, which draw increasing attention due to their resultant demasculinization and sexual disruption of aquatic organisms. Although there are a number of in vivo and in vitro studies investigating the combined effects of antiandrogen mixtures, these studies are mainly on selected model compounds such as flutamide, procymidone, and vinclozolin. The aim of the present study is to investigate the combined antiandrogenic effects of parabens, which are widely used antiandrogens in industrial and domestic commodities. A yeast-based human androgen receptor (hAR) assay (YAS) was applied to assess the antiandrogenic activities of n-propylparaben (nPrP), iso-propylparaben (iPrP), methylparaben (MeP), and 4-n-pentylphenol (PeP), as well as the binary mixtures of nPrP with each of the other three antiandrogens. All of the four compounds could exhibit antiandrogenic activity via the hAR. A linear interaction model was applied to quantitatively analyze the interaction between nPrP and each of the other three antiandrogens. The isoboles method was modified to show the variation of combined effects as the concentrations of mixed antiandrogens were changed. Graphs were constructed to show isoeffective curves of three binary mixtures based on the fitted linear interaction model and to evaluate the interaction of the mixed antiandrogens (synergism or antagonism). The combined effect of equimolar combinations of the three mixtures was also considered with the nonlinear isoboles method. The main effect parameters and interaction effect parameters in the linear interaction models of the three mixtures were different from zero. The results showed that any two antiandrogens in their binary mixtures tended to exert equal antiandrogenic activity in the linear concentration ranges. The antiandrogenicity of the binary mixture and the concentration of nPrP were fitted to a sigmoidal model if the concentrations of the other antiandrogens (iPrP, MeP, and PeP) in the mixture were lower than the AR saturation concentrations. Some concave isoboles above the additivity line appeared in all the three mixtures. There were some synergistic effects of the binary mixture of nPrP and MeP at low concentrations in the linear concentration ranges. Interesting, when the antiandrogens concentrations approached the saturation, the interaction between chemicals were antagonistic for all the three mixtures tested. When the toxicity of the three mixtures was assessed using nonlinear isoboles, only antagonism was observed for equimolar combinations of nPrP and iPrP as the concentrations were increased from the no-observed-effect-concentration (NOEC) to effective concentration of 80 %. In addition, the interactions were changed from synergistic to antagonistic as effective concentrations were increased in the equimolar combinations of nPrP and MeP, as well as nPrP and PeP. The combined effects of three binary antiandrogens mixtures in the linear ranges were successfully evaluated by curve fitting and isoboles. The combined effects of specific binary mixtures varied depending on the concentrations of the chemicals in the mixtures. At low concentrations in the linear concentration ranges, there was synergistic interaction existing in the binary mixture of nPrP and MeP. The interaction tended to be antagonistic as the antiandrogens approached saturation concentrations in mixtures of nPrP with each of the other three antiandrogens. The synergistic interaction was also found in the equimolar combinations of nPrP and MeP, as well as nPrP and PeP, at low concentrations with another method of nonlinear isoboles. The mixture activities of binary antiandrogens had a tendency towards antagonism at high concentrations and synergism at low concentrations. © 2014 Springer-Verlag Berlin Heidelberg.


Bao Q.,Tsinghua University | Chen L.,Tsinghua University | Chen L.,Zhejiang Provincial Key Laboratory of Water Science and Technology | Wang J.,Tsinghua University
Journal of Environmental Sciences (China) | Year: 2014

Diisopropylthiourea (DPT), an intermediate of a widely used cephalosporin, has been found to be one of the most refractory components in cephalosporin synthesis wastewater. This compound cannot be completely removed by conventional biological processes due to its antimicrobial property. Ionizing radiation has been applied in the decomposition of refractory pollutants in recent years and has proved effective. Therefore, the decomposition of DPT by γ-irradiation was studied. The compound was irradiated at the dose of 150-2000. Gy before a change of concentration and UV absorption of the solutions was detected. Furthermore, the decomposition kinetics and radiation yield (G-value) of DPT was investigated. The results of radiation experiments on DPT-containing aqueous showed that the DPT can be effectively degraded by γ-radiation. DPT concentration decreased with increasing absorbed doses. G-values of radiolytic decomposition for DPT (20. mg/L) were 1.04 and 0.47 for absorbed doses of 150 and 2000. Gy, respectively. The initial concentration and pH of the solutions affected the degradation. As the concentration of substrate increased, the decomposition was reduced. The decrease of removal rate and radiation efficacy under alkaline condition suggested that lower pH values benefit the γ-induced degradation. UV absorption from 190 to 250. nm decreased after radiation while that from 250 to 300. nm increased, indicating the formation of by-products. © 2014 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.


PubMed | Tsinghua University and Zhejiang Provincial Key Laboratory of Water Science and Technology
Type: | Journal: Chemosphere | Year: 2016

Adsorbable organic halogens (AOX) and total organic carbon (TOC) removal efficiencies in pharmaceutical wastewater treated by Fenton process under response surface methodology (RSM) optimized conditions were studied. High regression coefficient value R(2) (R(2)=0.9680, 0.9040 for AOX and TOC removal efficiency, respectively) and low value coefficient of variation (2.21%, 2.04% for AOX and TOC, respectively) of the quadratic model indicated that the model was accurate in predicting the experimental results. The desirability function was used to optimize AOX and TOC removal efficiencies simultaneously. The optimal pH, Fe(2+) concentration, molar ratio of H2O2/Fe(2+) and reaction time were found to be 3.3, 19.05mM, 20.16 and 2.2h, respectively, and 91.78% AOX and 75.01% TOC were removed under these conditions, which was validated. Furthermore, gas chromatography-mass spectrometer (GC-MS) results revealed that 28 out of 33 kinds of organic compounds, including 11 kinds of AOX were completely removed by the Fenton process while one new AOX compound, 4,5,6,7-tetrachlorophthalide, was produced which was the result of the carbonyl of 4,5,6,7-tetrachloro-1,3-isobenzofurandione being attacked in the Fenton reaction. These results indicated that analysis of organics was important since new AOX compounds could be produced in Fenton process despite the value of AOX decreasing.

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