Peifang Wang

Hohai University, Nan-ching, Jiangsu Sheng, China

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Publications (88)238.39 Total impact

  • Muhan Cao · Peifang Wang · Yanhui Ao · Chao Wang · Jun Hou · Jin Qian
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    ABSTRACT: Hydrogen evolution by photocatalytic water splitting has attracted extensive attention in recent years. Here we report a composite photocatalyst, in which graphene and Pt particles act as cocatalysts to modify CdS nanowires. This composite photocatalyst was prepared by a solvothermal method followed by a photoreduction process. The obtained samples were characterized by X-ray powder diffraction, UV-vis diffuse reflectance spectroscopy, scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, photoluminescence and Brunauer-Emmett-Teller specific surface area analysis. The graphene and Pt comodified CdS nanowires gain a high hydrogen evolution rate of 3984 μmol h(-1) g(-1), which is almost 4 times higher than that of bare CdS nanowires and also higher than the sum of graphene-CdS and Pt-CdS nanowires. The obtained sample also exhibits a good stability. The encouraging results presented here can be attributed to the incorporation of graphene and Pt which show a synergetic effect for hydrogen evolution. This work paves a way to the potential application of CdS nanowires in energy conversion.
    Dalton Transactions 08/2015; DOI:10.1039/c5dt02266e · 4.20 Impact Factor
  • Lihua Niu · Yi Li · Peifang Wang · Wenlong Zhang · Chao Wang · Qing Wang
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    ABSTRACT: To understand the relationship between elevation and bacterial communities in wastewater treatment plants (WWTPs), bacterial communities were investigated by 454-pyrosequencing in twenty-one municipal WWTPs located at 9 to 3660 meters above sea level (masl) across China. A threshold of elevation associated with bacterial community richness and evenness was observed at approximately 1200 masl. At lower elevations, both richness and evenness were not significantly associated with elevation. At higher elevations, significant decline trends with elevation were observed in community richness and evenness. The declining evenness trend at the phylum level was reflected by distinct trends of individual bacterial phyla in relative abundance. Betaproteobacteria, Bacteroidetes, and Firmicutes displayed significantly increasing trends, while most others declined. Spearman correlation analysis indicated that the community richness and evenness at high elevations were more correlated with elevation than any other single environmental variable. Redundancy analysis indicated that the contribution of elevation to community composition variances increased from 3% at lower elevations to 11% at higher elevations, whereas the community composition variance at higher elevations remained much more explained by operational variables (39.2%) than elevation. The influent total phosphorus concentration, food/microorganism ratio, and treatment process were the three shared dominant contributors to the community composition variance across the whole elevational gradient, followed by effluent ammonia nitrogen and temperature at higher elevations. Copyright © 2015, American Society for Microbiology. All Rights Reserved.
    Applied and Environmental Microbiology 07/2015; DOI:10.1128/AEM.01842-15 · 3.95 Impact Factor
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    Guoxiang You · Jun Hou · Yi Xu · Chao Wang · Peifang Wang · Lingzhan Miao · Yanhui Ao · Yi Li · Bowen Lv
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    ABSTRACT: Extracellular polymeric substances (EPS) are a major component of biofilms that act as a gel-like matrix, binding the cells together to form their three-dimensional structure. The effects of ceria nanoparticles (CeO2 NPs) on the production and physicochemical characteristics of EPS in biofilms in a sequencing batch biofilm reactor were investigated. Total EPS production, including loosely bound EPS (LB-EPS) and tightly bound EPS (TB-EPS), increased by 35.41% compared to in control tests without CeO2 NPs. Protein production increased by 47.02% (LB-EPS) and 58.83% (TB-EPS) after 50mg/L CeO2 NP exposure. Three-dimensional excitation-emission fluorescence spectra revealed that tyrosine (LB-EPS) and aromatic (TB-EPS) protein-like substances formed after CeO2 NP exposure. Fourier transform infrared spectroscopy results indicated the susceptibility of -OH and -NH2 in EPS hydroxyl and amine groups to CeO2 NPs. Exposure to 50mg/L CeO2 NPs reduced the flocculating capacity of LB-EPS (51.78%) and TB-EPS (17.14%), consistent with the decreased zeta potential. Copyright © 2015. Published by Elsevier Ltd.
    Bioresource Technology 07/2015; 194:91-98. DOI:10.1016/j.biortech.2015.07.006 · 5.04 Impact Factor
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    yanhui Ao · Liya xu · Peifang Wang · Chao Wang · jun hou · jin qian
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    ABSTRACT: In this work, a series of novel flower-like Bi2O2CO3/CdS heterojunctions were prepared by a simple and feasible two-step process. The phase structures of as-prepared samples were examined by X-ray diffraction (XRD). Scanning electron microscopy (SEM), Transmission Electron Microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) were used to confirm the flower-like heterostructures of the Bi2O2CO3/CdS composites. The Brunauer-Emmett-Teller (BET) specific surface area (SBET) of samples were analyzed by N2 adsorption-desorption isotherms. UV-vis diffuse reflectance spectrometry (DRS) revealed that Bi2O2CO3/CdS heterojunctions exhibited better light absorptive properties than pure Bi2O2CO3. The photocatalytic activity was investigated by the degradation of MB under visible light irradiation. The results showed that the as-prepared Bi2O2CO3/CdS heterojunctions exhibited much higher activity than pure Bi2O2CO3. The photoluminescence (PL) spectra and photocurrent studies indicated that the recombination of photogenerated electron-hole pairs was decreased effectively due to the formation of heterojunctions between flower-like Bi2O2CO3 and CdS nanoparticles. Trapping experiments indicated that ˙O(2-) radicals were the main reactive species for MB degradation in the present photocatalytic system. Furthermore, the cycling experiments revealed the good stability of Bi2O2CO3-CdS composites.
    Dalton Transactions 05/2015; DOI:10.1039/C5DT01168J · 4.20 Impact Factor
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    Zhiyuan Wang · Chao Wang · Peifang Wang · Jin Qian · Jun Hou · Yanhui Ao · Baohai Wu
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    ABSTRACT: This study aimed to investigate the performance of chitosan-modified nano-sized montmorillonite (CTS/NMMT) during the flocculation of Microcystis aeruginosa (MA). The release of intracellular microcystins (MCs) caused by the damage of intact MA cells during the flocculation and floc storage processes was also comprehensively evaluated through scanning electron microscopy (SEM) and measurement of K(+) and Mg(2+) release. With the application of the Box-Behnken experimental design combined with response surface methodology, the quadratic statistical model was established to predict and optimize the interactive effects of content of CTS/NMMT, weight ratio of NMMT to CTS, and agitation time on the removal efficiency of MA cells. A maximum removal of 94.7 % MA cells was observed with content of CTS/NMMT 300-320 mg L(-1), weight ratio of NMMT to CTS 14-16, and agitation time 16-50 min. During the flocculation process, CTS/NMMT aggregated MA cells as flocs and served as a protection shield for cells. The extracellular and intracellular microcystin-leucine-arginine (MC-LR) decreased remarkably and the yield of intracellular MC-LR showed a decreasing trend during the flocculation. The cell integrity was slightly damaged by the mechanical actions rather than by the flocculant. During the floc storage process, cell lysis and membrane damage were remarkably aggravated. The noticeable increase of K(+) and Mg(2+) release indicated that CTS/NMMT damaged the integrity of most MA cells in the flocs and liberated the intracellular MC-LR. Meanwhile, NMMT and CTS polymers assisted the adsorptive removal of extracellular MC-LR released to water. The flocs should be timely treated within 12 h to prevent the leakage of MCs.
    Environmental Science and Pollution Research 05/2015; DOI:10.1007/s11356-015-4412-z · 2.76 Impact Factor
  • Songhe Zhang · Bing Han · Ju Gu · Chao Wang · Peifang Wang · Yanyan Ma · Jiashun Cao · Zhenli He
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    ABSTRACT: Antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) are emerging contaminants of environmental concern. Heterotrophic bacteria in activated sludge have an important role in wastewater treatment plants (WWTPs). However, the fate of cultivable heterotrophic ARB and ARGs in WWPTs process remains unclear. In the present study, we investigated the antibiotic-resistant phenotypes of cultivable heterotrophic bacteria from influent and effluent water of three WWTPs and analysed thirteen ARGs in ARB and in activated sludge from anoxic, anaerobic and aerobic compartments. From each influent or effluent sample of the three plants, 200 isolates were randomly tested for susceptibility to 12 antibiotics. In these samples, between 5% and 64% isolates showed resistance to >9 antibiotics and the proportion of >9-drug-resistant bacteria was lower in isolates from effluent than from influent. Eighteen genera were identified in 188 isolates from influent (n=94) and effluent (n=94) of one WWTP. Six genera (Aeromonas, Bacillus, Lysinibacillus, Microbacterium, Providencia, and Staphylococcus) were detected in both influent and effluent samples. Gram-negative and -positive isolates dominated in influent and effluent, respectively. The 13 tetracycline-, sulphonamide-, streptomycin- and β-lactam-resistance genes were detected at a higher frequency in ARB from influent than from effluent, except for sulA and CTX-M, while in general, the abundances of ARGs in activated sludge from two of the three plants were higher in aerobic compartments than in anoxic ones, indicating abundant ARGs exit in the excess sledges and/or in uncultivable bacteria. These findings may be useful for elucidating the effect of WWTP on ARB and ARGs. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Chemosphere 05/2015; 135:138-145. DOI:10.1016/j.chemosphere.2015.04.001 · 3.50 Impact Factor
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    ABSTRACT: Abstract The effect of the water matrix components of a secondary effluent of a urban wastewater treatment plant on the photocatalytic activity of Ag/AgCl @ chiral TiO2 nanofibers and the undergoing reaction mechanisms were investigated. These effects were evaluated through the water components-induced changes on the net rate of hydroxyl radical (OH) generation and modeled using a relative rate technique. Dissolved organic matter DOM (k = −2.8 × 108 M−1 s−1) scavenged reactive oxygen species, Cl− (k = −5.3 × 108 M−1 s−1) accelerated the transformation from Ag to AgCl (which is not photocatalytically active under visible-light irradiation), while Ca2+ at concentrations higher than 50 mM (k = −1.3 × 109 M−1 s−1) induced aggregation of Ag/AgCl and thus all of them revealed inhibitory effects. In contrast, NO3− (k = 6.9 × 108 M−1 s−1) and CO32− (k = 3.7 × 108 M−1 s−1) improved the photocatalytic activity of Ag/AgCl slightly by improving the rate of HO generation. Other ubiquitous secondary effluent components including SO42− (k = 3.9 × 105 M−1 s−1), NH3+ (k = 3.5 × 105 M−1 s−1) and Na+ (k = 2.6 × 104 M−1 s−1) had negligible effects. 90% of 17-α-ethynylestradiol (EE2) spiked in the secondary effluent was removed within 12 min, while the structure and size of Ag/AgCl @ chiral TiO2 nanofibers remained stable. This work may be helpful not only to uncover the photocatalytic mechanism of Ag/AgCl based photocatalyst but also to elucidate the transformation and transportation of Ag and AgCl in natural water.
    Journal of Hazardous Materials 03/2015; 285:277 - 284. DOI:10.1016/j.jhazmat.2014.10.060 · 4.33 Impact Factor
  • Chao Wang · Huagang Zhu · Peifang Wang · Jun Hou · Yanhui Ao · Xiulei Fan
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    ABSTRACT: Sedimentary biogenic silica (BSi) is an important parameter for understanding biogeochemical processes in estuarine ecosystems. In this study, a two-step mild acid–mild alkaline extraction procedure was used to leach BSi and its early diagenetic products from the sediments of the Yangtze Estuary. A Si/Al correction of the mild alkaline leachable silica (Si-Alk) was applied to estimate the contents of BSi in the sediments. The BSi contents varied from 18.90 to 120.10 μmol Si/g in the sediments, whereas mild acid leachable silica (Si-HCl) and Si-Alk levels ranged from 17.43 to 73.56 and from 19.56 to 185.63 μmol Si/g, respectively. Furthermore, the degrees of diagenetic alteration of biogenic and reactive silica were also calculated and discussed. The diagenetic alteration ratios of biogenic and reactive silica increased seaward during May, August and November 2012, whereas an opposite trend was observed in March 2013. The diagenetic alteration of the biogenic and reactive silica was mainly controlled by the redox conditions in benthic sediments. Additionally, the deposition of fresh diatoms and authigenic products could temporarily affect the distribution of silica pools in the sediments and ultimately affect the diagenetic alteration ratios of biogenic and reactive silica. Detailed investigations are still necessary to understand the early diagenetic processes of biogenic and reactive silica in this warm temperate area.
    Continental Shelf Research 03/2015; 99. DOI:10.1016/j.csr.2015.03.003 · 2.12 Impact Factor
  • Muhan Cao · Peifang Wang · Yanhui Ao · Chao Wang · Jun Hou · Jin Qian
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    ABSTRACT: A magnetically separable graphene-TiO2 (MG-TiO2) hybrid photocatalyst was successfully prepared by a one step method. Namely, simultaneous reduction of graphene oxide and deposition of TiO2 on the graphene was occurred in one single process. The as-prepared samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectroscopy (DRS), photoluminescence (PL) analysis, X-ray photoelectron spectroscopy (XPS) and The Brunauer-Emmett-Teller (BET) analysis. The photocatalytic activity of the obtained samples was measured by the decomposition of methylene blue (MB) and tetrabromobisphenol A (TBBPA, a brominated flame retardant) under UV light irradiation. The results showed that MG-TiO2 exhibited much higher photocatalytic performance than that of bare TiO2. The enhanced activity can be ascribed to the incorporation of graphene. In addition, the MG-TiO2 with MG content of 3% exhibited the highest activity towards MB and TBBPA degradation. The intermediates of TBBPA in the photocatalytic degradation process were analyzed by LC-MS. On the basis of the identified intermediates, the photocatalytic degradation pathway of TBBPA was proposed. Furthermore, the recyclable ability of the samples was also studied and the results showed that the samples exhibited high stability.
    Chemical Engineering Journal 03/2015; 264:113-124. DOI:10.1016/j.cej.2014.10.011 · 4.32 Impact Factor
  • Chi Zhang · Yi Li · Dawei Wang · Wenlong Zhang · Qing Wang · Yuming Wang · Peifang Wang
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    ABSTRACT: Ag-modified helical chiral TiO2 NFs (Ag@chiral TiO2 NFs) were fabricated and characterized by ultraviolet-visible absorption spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. This novel material exhibited efficient photocatalytic activity for the degradation of 17α-ethinylestradiol (EE2) in water under visible light irradiation with an optimum size of deposited silver nanoparticles (Ag NPs) in the range of 12 ∼ 14 nm. The pseudo-first-order rate constant (k obs) for EE2 photodegradation by Ag@chiral TiO2 NFs increased by up to a factor of 20.1 when compared with that of pure chiral TiO2 NFs. The high photocatalytic activity can be attributed to the interactions between helical chiral TiO2 NFs and surface plasmon resonance effect of Ag NPs. The new catalyst retains its photocatalytic activity at least up to five consecutive cycles. The results clearly demonstrate the feasibility of using Ag@chiral TiO2 NFs for the photocatalytic removal of EE2 and other endocrine-disrupting chemicals from water.
    Environmental Science and Pollution Research 02/2015; 22(14). DOI:10.1007/s11356-015-4251-y · 2.76 Impact Factor
  • Peifang Wang · Bin Hu · Chao Wang · Yang Lei
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    ABSTRACT: The process of phosphorus (P) transformation in particulate matter during sediment resuspension and sedimentation was studied. The P-binding forms in resuspended particles (RP) and settled particles (SP) were analyzed by sequential fractionation (modified Psenner method) and an extended extraction with ammonium oxalate. Water quality data and P fractions were used to estimate P release and uptake by the resuspended and settling sediment particles. Results of 8-h resuspension experiments showed increases of dissolved oxygen, pH, total phosphorus, and particulate phosphorus in overlying water, but no change in soluble reactive phosphorus (SRP). P fractions extracted with common sequential fractionation showed that the increase of total P in RP was mainly due to increases of redox-sensitive bound P BD (BD-SRP) and P bound to Al and Fe oxides (NaOH-SRP) (36-52 % and 30-36 % of total increased P, respectively). Comparisons between two sequential fractionations indicated that inorganic P extracted with ammonium oxalate consisted of P bound to amorphous Fe/Al oxy-hydroxides and partially of carbonate-bound P (HCl-SRP) and that increased P in RP was mainly caused by increases in P bound to amorphous oxides. It is concluded that the formation of amorphous oxides and subsequent adsorption of P lead to the increase of P in RP. However, P adsorbed by amorphous oxy-hydroxides in RP is unstable and may be released under sedimentation conditions. Meanwhile, increases in HCl-SRP, refractory P, and crystalline Fe-P were found in SP compared with RP. NaOH-SRP in SP increased gradually under sedimentation conditions. It is suggested that, during sedimentation, mobile P can be transformed to non-mobile P forms that provide long-term P retention. The findings contribute to the understanding of P cycling in particulate matter during sediment resuspension and sedimentation.
    Environmental Science and Pollution Research 02/2015; 22(9). DOI:10.1007/s11356-015-4114-6 · 2.76 Impact Factor
  • Nan Geng · Chao Wang · Peifang Wang · Ning Qi · Lingxiao Ren
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    ABSTRACT: Freshwater bivalves such as Corbicula fluminea (Müller) are useful biomonitors for cadmium pollution because they absorb heavy metals and accumulate them in their tissues. We exposed C. fluminea in the laboratory to natural and cadmium (Cd)-spiked sediments below flowing water in order to evaluate the organisms' Cd accumulation and metallothionein (MT) response under hydrodynamic conditions. The accumulation of Cd and the induction of MT in C. fluminea were determined at 0, 1, 3, 6, 10, 16, and 23 days. Hydrodynamic conditions, represented by a water flow rate of 14 or 3.2 cm/s, increased Cd accumulation in the visceral mass, gill, foot, and mantle of C. fluminea in the first 3 or 6 days in the natural sediment. Cd concentrations in the C. fluminea tissues kept increasing over time in the three treatments, and significant differences were observed in Cd accumulation after 6 (visceral mass), 10 (foot) and 16 (gill and mantle) days among the three groups. The MT concentrations were barely affected by hydrodynamic conditions and were significantly linearly related to the Cd concentration in the visceral mass in the natural sediment and binomially related to it in the Cd-spiked sediment. Hydrodynamic conditions enhanced the accumulation of Cd in the soft tissues of C. fluminea, especially in the Cd-spiked sediment, but stronger hydrodynamic forces did not increase Cd accumulation. MT may be considered an indicator for Cd accumulation in C. fluminea under hydrodynamic conditions, but only when the Cd concentrations in the tissue remain below the toxic threshold values.
    Biological Trace Element Research 02/2015; 165(2). DOI:10.1007/s12011-015-0266-y · 1.61 Impact Factor
  • Zhiyuan Wang · Chao Wang · Peifang Wang · Jin Qian · Jun Hou · Yanhui Ao
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    ABSTRACT: The adsorptive removal of the most commonly occurring cyanobacterial toxin microcystin-LR by polyacrylamide/sodium alginate-modified montmorillonite (PAM/SA-MMT) superabsorbent nanocomposite was investigated through the HPLC/UV system. The process of PAM/SA-MMT preparation and MC-LR adsorption was characterized by scanning electron microscopy, energy dispersive X-ray microanalysis, X-ray diffraction analysis, and Fourier transform infrared spectroscopy analysis. With the application of Box-Behnken statistical experimental design combined with Response surface methodology, the quadratic statistical model was established to predict the interactive effects of pH, weight ratio (wr) of AM to SA, and weight content (wt) of MMT on MC-LR adsorption and to optimize the main controlling parameters. The maximum adsorption capacity was observed with pH 2.5-4.5, wr 55-65, and wt3-5%. The MC-LR adsorption capacity of PAM/SA-MMT increased with increase in temperature from 10 to 40°C. Kinetics were consistent with Pseudo models and revealed that the sorption process could reach the equilibrium within 80 min and involved several different rate-controlling kinetic stages. The Langmuir isotherm model predicted that the theoretical maximum adsorption capacity of PAM/SA-MMT was 32.66 mg g−1. Over 85% adsorption and 80% desorption could be achieved after five regeneration cycles and the recovery of MC-LR reached 92.8% without ionic effect. PAM/SA-MMT superabsorbent nanocomposite was determined as effective, economic, and environmentally benign for MC-LR removal on a large-scale application.
    Desalination and water treatment 02/2015; DOI:10.1080/19443994.2015.1006261 · 1.17 Impact Factor
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    ABSTRACT: The unsaturated fatty acid (linoleic acid) sustained-release microspheres were prepared with linoleic acid (LA) using alginate–chitosan microcapsule technology. These LA sustained-release microspheres had a high encapsulation efficiency (up to 62%) tested by high performance liquid chromatography with a photo diode array. The dry microspheres were characterized by a scanning electron microscope, X-ray diffraction measurement, dynamic thermogravimetric analysis and Fourier transform infrared spectral analysis. The results of characterization showed that the microspheres had good thermal stability (decomposition temperature of 236 °C), stable and temperature independent release properties (release time of more than 40 d). Compared to direct dosing of LA, LA sustained-released microspheres could inhibit Microcystis aeruginosa growth to the non-growth state. The results of this study suggested that the LA sustained-release microspheres may be a potential candidate for algal inhibition.
    Chemosphere 02/2015; 120:383–390. DOI:10.1016/j.chemosphere.2014.07.098 · 3.50 Impact Factor
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    Jun Hou · Lingzhan Miao · Chao Wang · Peifang Wang · Yanhui Ao · Bowen Lv
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    ABSTRACT: The effects of CuO nanoparticles (NPs) on the production and composition of extracellular polymeric substances (EPS) and the physicochemical stability of activated sludge were investigated. The results showed enhanced production of loosely bound extracellular polymeric substances (LB-EPS), protecting against nanotoxicity. Specifically, polysaccharide production increased by 89.7% compared to control upon exposure to CuO NPs (50mg/L). Fourier transform-infrared spectroscopy analysis revealed changes in the polysaccharide COC group and the carboxyl group of proteins in the EPS in the presence of CuO NPs. The sludge flocs were unstable after exposure to CuO NPs (50mg/L) because of excess LB-EPS. This also corresponded with decreased cell viability of the sludge flocs, as determined by the production of reactive oxygen species and the release of lactate dehydrogenase. These results are key to assessing the adverse effects of the CuO NPs on activated sludge in wastewater treatment plants. Copyright © 2014 Elsevier Ltd. All rights reserved.
    Bioresource Technology 01/2015; 176:65-70. DOI:10.1016/j.biortech.2014.11.020 · 5.04 Impact Factor
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    ABSTRACT: Simultaneous measurements of dissolved iron (Fe), phosphorus (P), and arsenic (As) were made using the diffusive gradients in thin films technique equipped with a mixed binding gel impregnated with zirconium oxide and Chelex-100 (ZrO–Chelex DGT). The ZrO–Chelex binding gel exhibited rapid binding dynamics to Fe(II), P(PO43−), and As(III)/As(V) in mixed solutions of the three elements. The bound Fe, P, and As could be quantitatively recovered using an established four-step elution procedure. Simultaneous measurements of the three elements with ZrO–Chelex DGT were validated through time-series experiments, and there was no influence of pH (4.1 to 7.1) and ionic strength (0.01 to 800 mM). The DGT capacities for As(III) and As(V) were 69.0 μg and 186 μg per device, respectively, which were much greater than those of the widely used ferrihydrite DGT. Applications in synthesized freshwaters and in sediments further confirmed its feasibility in simultaneous measurements in the environment. The present study offered that the ZrO–Chelex DGT will be a useful tool in in situ monitoring of Fe–P–As and assessment of their interactions in the biogeochemical processes.
    Environmental Sciences: Processes and Impacts 01/2015; 17(3). DOI:10.1039/C4EM00629A
  • Chao Wang · Di Wu · Peifang Wang · Yanhui Ao · Jun Hou · Jin Qian
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    ABSTRACT: Partially reduced ZnO nanorod arrays (NRAs) were synthesized in a reducing reagent of NaBH4. The NaBH4 treatment substantially increased the density of oxygen vacancies. The obtained materials were characterized by a field emission scanning electron microscopy, X-ray diffractometer, X-ray photoelectron spectroscopy and UV–vis absorption spectra. The photocatalytic activity of the resulting samples was evaluated by degradation of methylene blue (MB) under UV light irradiation. The ZnO NRAs with a partially reduced surface exhibited enhanced photocatalytic activity. The improvement was ascribed to the introducing oxygen vacancies in ZnO by NaBH4 treatment. The increased surface oxygen vacancy decreased the surface recombination centers, and improved the charge separation efficiency, thus enhances the photocatalytic activity. Furthermore, we found that moderate treatment enhanced photocatalytic activity. However, with longer time of treatment, bulk oxygen vacancies appeared, which would cause a reduced activity.
    Applied Surface Science 01/2015; 325:112-116. DOI:10.1016/j.apsusc.2014.11.003 · 2.54 Impact Factor
  • Muhan Cao · Peifang Wang · Yanhui Ao · Chao Wang · Jun Hou · Jin Qian
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    ABSTRACT: A series of GO modified AgCl/Ag3PO4 composites were prepared by a simple method. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–vis diffuse reflectance spectra (DRS) analysis and Brunauer–Emmett–Teller (BET) specific surface area analysis. The photocatalytic performance of the samples was measured by the degradation of dye methylene blue (MB) and O2 evolution under visible light irradiation. The results indicated that the couple of AgCl and GO could effectively enhance the photoactivity and stability in comparison with bare Ag3PO4. From the analysis, it can be inferred that GO sheets could accelerate the separation of electron–hole pairs and also improve the light absorption ability in comparison with bare Ag3PO4 and AgCl/Ag3PO4. Additionally, an optimum amount of GO added in the composite was obtained.
    International Journal of Hydrogen Energy 01/2015; 40(2). DOI:10.1016/j.ijhydene.2014.09.175 · 2.93 Impact Factor
  • Yanhui Ao · Dandan Wang · Peifang Wang · Chao Wang · Jun Hou · Jin Qian
    RSC Advances 01/2015; 5(67):54613-54621. DOI:10.1039/C5RA05473G · 3.84 Impact Factor
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    ABSTRACT: Heavy metal pollution has become an increasingly recognized threat to the aquatic environment. In response to heavy metal stresses, various terrestrial plants produce the hormone nitric oxide (NO), but minimal information is available about the role of NO in aquatic macro-phytes under high zinc (Zn) stress. In this study, we measured physiochemical parameters in the leaves of Hydrilla verticillata exposed to Zn2+ (10 mg l(-1)) alone or combined with NO (supplied as sodium nitroprusside, SNP) for 1 d and 4 d. Excess Zn disturbed nutrient uptake and altered the redox status of the aquatic plants. NO application partially reversed negative impacts of Zn stress on the contents of photosynthetic pigments, malondialdehyde, nutrient concentration, ascorbic acid, and the activity of antioxidant enzymes. However, the metabolites of SNP did not have similar effects. After treatments for 4 d, plants were further cultured in a solution containing Zn2+ (10 mg l(-1)) for 10 d. NO application partially reversed Zn-induced negative effects in parameters such as nutrient uptake, antioxidant enzymatic activities, and biomass, as compared to treatments with Zn alone. These results indicate that NO supply could mitigate Zn stress in H. verticillata, as a defense mechanism of the plant against Zn toxicity.
    Aquatic Biology 12/2014; 23(1):61-69. DOI:10.3354/ab00608 · 1.12 Impact Factor

Publication Stats

448 Citations
238.39 Total Impact Points

Institutions

  • 2007–2015
    • Hohai University
      • Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education
      Nan-ching, Jiangsu Sheng, China