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Feng Z.,Zhejiang University | Zhu L.,Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control
Science of the Total Environment | Year: 2017

Biochar amendment has been proposed as a potential solution for improving soil quality and suppressing greenhouse gas emission. Considering the serious nitrogen fertilizer overuse problem in China, it is important to investigate the effect of biochar on soil with excess nitrogen fertilizer. Therefore, two sets of soil column experiments were conducted to explore the effect of biochar on N2O emission from nitrogen fertilizer-overused soil. Three types of biochar (biochars pyrolzed at 300, 500 and 700°C, respectively) and one type of nitrogen fertilizer (ammonium sulfate) were investigated at varying application rates. It was found that N2O emission was related to both biochar and N-fertilizer application rates, and increased N2O emission was negatively correlated with the TC/IN ratio (the ratio of total carbon to inorganic nitrogen) after biochar application. The soil TC/IN ratio determined the ammonium utilization pathway, affecting the intensity of nitrification and N2O emission. When the TC/IN ratio was relatively high (>60), suppressed nitrification led to the suppression of N2O emission. Conversely, enhanced nitrification when the TC/IN ratio was relatively low (<45) caused the promotion of N2O emission. In conclusion, biochar's suppression of soil N2O emission was conditional and biochar should be applied in a proper ratio to nitrogen fertilizer to avoid excessive N2O emission. © 2017 Elsevier B.V.

Zhuang S.,Zhejiang University | Zhuang S.,Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control | Zhang C.,University of Houston-Clear Lake | Liu W.,Zhejiang University
Chemical Research in Toxicology | Year: 2014

Bisphenol A analogues (BPAs) belong to a wide variety of large volume chemicals with diverse applications yet emerging environmental concerns. Limited experimental data have demonstrated that BPAs with different halogenation patterns distinctly affect the agonistic activities toward proliferator-activated receptor (PPAR)γ and estrogen receptors (ER)α. Understanding the modes of action of BPAs toward di fferent receptors is essential, however, the underlying molecular mechanism is still poorly understood. Here we probed the molecular recognition process of halogenated BPAs including TBBPA, TCBPA, BPAF, BPC, triBBPA, diBBPA, and monoBBPA toward PPARγ and ERα by molecular modeling, especially the impact of different halogen patterns. Increasing bromination at phenolic rings of BPAs was found highly correlated with electrostatic interactions (R2 = 0.978 and 0.865 toward PPARγ and ERα, respectively) and van der Waals interactions (R2 = 0.995 and 0.994 toward PPARγ and ER α, respectively). More halogenated phenolic rings at 3,5-positions of BPAs increase the shielding of the hormonally active phenolic OH and markedly decrease electrostatic interactions favorable for agonistic activities toward PPARγ, but unfavorable for agonistic activities toward ERα. The halogenation at the phenolic rings of BPAs exerts more impact on molecular electrostatic potential distribution than halogenation at the bridging alkyl moiety. Di fferent halogenations further alter hydrogen bond interactions of BPAs and induce conformational changes of PPARγ ligand binding domain (LBD) and ERα LBD, specifically affecting the stabilization of helix H12 attributable to the different agonistic activities. Our results indicate that structural variations in halogenation patterns result in different interactions of BPAs with PPARγ LBD and ERα LBD, potentially causing distinct agonistic/antagonistic toxic effects. The various halogenation patterns should be fully considered for the design of future environmentally benign chemicals with reduced toxicities and desired properties. (Chemical Equation Presented). © 2014 American Chemical Society.

Zhang J.,Zhejiang University | Zhang J.,Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control | Ding T.,Zhejiang University | Ding T.,Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control | Zhang C.,University of Houston-Clear Lake
Chemosphere | Year: 2013

Toxicity and biosorption responses to arsenite (As[III]) were examined in a 96-h exposure study using Scenedesmus quadricauda, one of the most popular green algae distributed in freshwaters in China. Results indicated that the pH-dependent distribution of two arsenite species (H2AsO3- and H3AsO3) played an important role in biosorption and toxicity. The undissociated H3AsO3 was more toxic than its monoanionic H2AsO3- through comparison of algal cell numbers, chlorophyll-a contents, and algal ultrastructural changes observed with transmission electron microscopy. An effective biosorption of 89.0mgg-1 at 100mgL-1 As[III] was found in the treatments with an initial pH of 9.3 and 25.2μgg-1 at 0.03mgL-1 As[III] at an initial pH of 8.2 as a result of the predominant species of H2AsO3- under the ambient pH and Eh conditions. Our results imply that S. quadricauda may provide a new means for the removal of toxic arsenite species present in contaminated surface water. © 2013 Elsevier Ltd.

Zhong Y.,Zhejiang University | Zhong Y.,Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control | Zhu L.,Zhejiang University | Zhu L.,Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control
Science of the Total Environment | Year: 2013

Given the steel industry park-city paired structure commonly found across China and it associated environmental pollution, the objective of this study was to examine the spatial-temporal distributions of polycyclic aromatic hydrocarbons (PAHs) as well as the relative contributions of the main influx pathways in Banshan steel industry park, China. We analyzed the concentrations of 16 PAHs in soil, air, water and dry/wet deposition samples using gas chromatography-mass spectrometry (GC-MS). The concentrations of ∑16-PAHs ranged from 572 to 4654μg/kg in April 2010; and the average concentration is 12.7% and 26.1% higher than that of April 2009 and April 2008, respectively, mainly due to the rapid increase of highly toxic high molecular weight (MW) PAHs. The principal input pathway for high and low MW PAHs was determined to be dry deposition (e.g., 69.73% for Benzo[a]pyrene) and wet deposition (e.g., 78.87% for Naphthalene), respectively. Together, 54.79% of total PAHs found in this region are via dry deposition, whereas wet deposition and river water irrigation contribute to 25.46% and 19.76% (corrected with toxic equivalency factors). The approach to the soil-air equilibrium was assessed by calculating fugacity quotients between soil and air samples, and the results indicate that the soil acted as a secondary source for light MW atmospheric PAHs and a sink for higher MW PAHs. It was also determined that the soil acted as a source for median MW PAHs, particularly PY. © 2012 Elsevier B.V..

Fang Q.,Zhejiang University | Fang Q.,Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control | Chen B.,Zhejiang University | Chen B.,Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control
Journal of Materials Chemistry A | Year: 2014

Self-assembly based on graphene building blocks are an important strategy for three-dimensional (3D) architectures, but their fabrication and application in water purification remain challenging. Here, we report a facile one-step approach to prepare 3D graphene oxide (GO) hydrogels and aerogels containing nanoscaled layered double hydroxides (LDHs). The LDHs acted as cross-linking agent molecules ("buttons") to join GO nanosheets into a 3D network via charge-assisted hydrogen bonds and lattice-lattice cation-π interactions. The resultant aerogels exhibited high hydrophilicity and excellent structural stability/plasticity in water environments, which guarantee the availability of their effective active sites in aqueous solution and overcome the utilization restrictions of neat GO aerogels due to their fragile morphology. The obtained LDH + GO aerogels showed a high capability for removal of dye (methylene blue) and heavy metal (Cd2+) pollutants from water. The addition of LDH nanoparticles assisted the aerogels in maintaining their 3D monoliths and made it easy for separation and collection after use, and improved the adsorption capacities for environmental pollutants via reducing the stacking of GO sheets and exposing more active adsorption sites. Thus the obtained LDH + GO aerogels have a great potential for water purification as highly efficient and stable adsorbents. This journal is © the Partner Organisations 2014.

Li M.,Zhejiang University | Li M.,Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control | Lin D.,Zhejiang University | Lin D.,Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control | And 2 more authors.
Environmental Pollution | Year: 2013

The dissolution of ZnO nanoparticles (nano-ZnO) plays an important role in the toxicity of nano-ZnO to the aquatic organisms. The effects of water chemistry such as pH, ionic components, and dissolved organic matter (DOM) on the dissolution of nano-ZnO and its toxicity to Escherichia coli (E. coli) were investigated in synthetic and natural water samples. The results showed that the toxicity of nano-ZnO to E. coli depended on not only free Zn2+ but also the coexisting cations which could reduce the toxicity of Zn2+. Increasing solution pH, HPO42-, and DOM reduced the concentration of free Zn2+ released from nano-ZnO, and thus lowered the toxicity of nano-ZnO. In addition, both Ca2+ and Mg2+ dramatically reduced the toxicity of Zn2+ to E. coli. These results highlight the importance of water chemistry on the toxicity evaluation of nano-ZnO in natural waters. © 2012 Elsevier Ltd. All rights reserved.

Zhang D.,Zhejiang University | Zhang D.,Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control | Zhu L.,Zhejiang University | Zhu L.,Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control
Environmental Pollution | Year: 2012

The sorption and biodegradation of pyrene by Klebsiella oxytoca PYR-1 (PYR-1) in the presence of nonionic surfactant Tween 80 were investigated toward a better understanding that how surfactants can affect biodegradation of hydrophobic organic compounds. The results indicated that Tween 80 can promote the removal, sorption and biodegradation of pyrene depending on the surfactant concentration, of which the most significant promotion of biodegradation was achieved at critical micelle concentration of Tween 80 with an improvement of 22.4%. A highly positive correlation (P < 0.0001) was observed between the biodegradation and sorption of pyrene with the presence of Tween 80. Biosorption experiments showed the same trends as biodegradation and further illustrated the improved biodegradation of pyrene was mainly due to surfactant-facilitated sorption. The regularly changes of cell surface hydrophobicity suggested formation of more hydrophobic surface caused by surfactant sorption lead to stimulation of pyrene sorption. © 2012 Elsevier Ltd. All rights reserved.

Li F.,Zhejiang University | Li F.,Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control | Li F.,Zhejiang Yuying College | Zhu L.,Zhejiang University | Zhu L.,Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control
Bioresource Technology | Year: 2012

In order to better understand how surfactants affect biodegradation of hydrophobic organic compounds (HOCs), Tween 80 and sodium dodecyl benzene sulfonate (SDBS), were selected to investigate effects on cell surface hydrophobicity (CSH), electron transport system (ETS) activities and phenanthrene biodegradation by Citrobacter sp. SA01. Tween 80 and SDBS increased CSH by 19.8-25.2%, ETS activities by 352.1-376.0 μmol/g. min, catechol 1,2-dioxygenase (C12) activities by 50.8-52.7. U/L, and phenanthrene biodegradation by 8.9-17.2% separately in the presence of 50. mg/L of surfactants as compared to in their absence. Lipopolysaccharide (LPS) release was 334.7 μg/mg in the presence of both surfactants whereas in their absence only 8.6-44.4 μg/mg of LPS was released. Thus, enhanced LPS release probably increased ETS and C12 activities as well as phenanthrene biodegradation by increasing CSH. The results demonstrate that surfactant-enhanced CSH provides a simple, yet effective strategy for field applications of surfactant-enhanced bioremediation of HOCs. © 2012 Elsevier Ltd.

Pei X.Q.,Zhejiang University | Song M.,Zhejiang University | Guo M.,Zhejiang University | Mo F.F.,Zhejiang University | And 2 more authors.
Atmospheric Environment | Year: 2013

Phthalate esters (PAEs) are ubiquitous in the indoor environment, owing to their use in consumer products. People spend a considerable amount of time indoors. As a result, human exposure to indoor contaminants is of great concern. People are exposed to phthalates through inhalation and dermal absorption of indoor air. In this study, the concentrations, characteristics and carcinogenic risks of gas-phase and particle-phase phthalates in indoor air from bedroom, living room and study room of 10 newly decorated apartments in Hangzhou, China were first investigated. The mean concentration of phthalates (gas-phase and particle-phase) present in household air was 12 096.4 ng m-3, of which diethyl phthalate (DEP), butylbenzyl phthalate (BBP) and di(2-ethylhexyl) phthalate (DEHP) were the most abundant compounds with concentrations of 2290 ng m-3, 3975 ng m-3 and 2437 ng m-3, respectively, totally accounting for 72.0% of 6PAEs. Contamination levels of phthalates varied in different compartments. The concentration of phthalates was the highest 17 363.7 ng m-3 in living room, followed with 11 389.5 ng m-3 in study room, and the lowest 9739.1 ng m-3 in bedroom. It was also found that phthalates mainly accumulated in gaseous form in household air. DEHP posed the greatest health risk to children aged 1-2. Carcinogenic risk of DEHP was evaluated to be 3.912 × 10-5, and was 39 times higher than the limit set by the U.S. EPA. © 2012 Elsevier Ltd.

Tong C.,Zhejiang University | Tong C.,Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control | Zhuo X.,Zhejiang University | Guo Y.,Zhejiang University
Journal of Agricultural and Food Chemistry | Year: 2011

A sensitive liquid chromatography-fluorescence detection method, combined with one-step solid-phase extraction, was established for detecting the residual levels of the four typical fluoroquinolone antibiotics (ofloxacin, norfloxacin, ciprofloxacin, and enrofloxacin) in influent, effluent, and surface waters from Hangzhou, China. For the various environmental water matrices, the overall recoveries were from 76.8 to 122%, and no obvious interferences of matrix effect were observed. The limit of quantitation of this method was estimated to be 17 ng/L for ciprofloxacin and norfloxacin, 20 ng/L for ofloxacin, and 27 ng/L for enrofloxacin. All of the four typical fluoroquinolone antibiotics were found in the wastewaters and surface waters. The residual contents of the four typical fluoroquinolone antibiotics in influent, effluent, and surface water samples are 108-1405, 54-429, and 7.0-51.6 ng/L, respectively. The removal rates of the selected fluoroquinolone antibiotics were 69.5 (ofloxacin), 61.3 (norfloxacin), and 50% (enrofloxacin), indicating that activated sludge treatment is effective except for ciprofloxacin and necessary to remove these fluoroquinolone antibiotics in municipal sewage. The risk to the aquatic environment was estimated by a ratio of measured environmental concentration and predicted no-effect concentration. At the concentrations, these fluoroquinolone antibiotics were found in influent, effluent, and surface waters, and they should not pose a risk for the aquatic environment. © 2011 American Chemical Society.

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