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ABSTRACT: Bioanodes formed at an optimal potential of 200mV vs. SHE and biocathodes developed at -300mV vs. SHE in bioelectrochemical cells (BECs) enhanced the subsequent performances of microbial fuel cells (MFCs) compared to the un-treated controls. While the startup times were reduced to 320h (bioanodes) and 420-440h (biocathodes), PCP degradation rates were improved by 28.5% (bioanodes) and 21.5% (biocathodes), and power production by 41.7% (bioanodes) and 44% (biocathodes). Accordingly, there were less accumulated products of PCP de-chlorination in the biocathodes whereas PCP in the bioanodes was more efficiently de-chlorinated, resulting in the formation of a new product of 3,4,5-trichlorophenol (24.3±2.2μM at 96h). Charges were diverted to more generation of electricity in the bioanodes at 200mV while oxygen in the biocathodes at -300mV acted as a primary electron acceptor. Dominant bacteria known as recalcitrant organic degraders and/or exoelectrogens/electrotrophs included Desulfovibrio carbinoliphilus and Dechlorospirillum sp. on the bioanodes at 200mV, and Desulfovibrio marrakechensis, Comamonas testosteroni and Comamonas sp. on the biocathodes at -300mV. These results demonstrated that an optimal potential was a feasible approach for developing both bioanodes and biocathodes for efficient PCP degradation and power generation from MFCs.
Bioelectrochemistry (Amsterdam, Netherlands) 05/2013; 94C:13-22. · 2.65 Impact Factor
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ABSTRACT: Silanol groups on a silica surface affect the activity of immobilized catalysts because they can influence the hydrophilicity/hydrophobicity, matter transfer, or even transition state in a catalytic reaction. Previously, these silanol groups have usually been passivated by using surface-passivation reagents, such as alkoxysilanes, bis-silylamine reagents, chlorosilanes, etc., and surface passivation has typically been found in mesoporous-silicas-supported molecular catalysts and heteroatomic catalysts. However, this property has rarely been reported in mesoporous-silicas-supported metal-nanoparticle catalysts. Herein, we prepared an almost-superhydrophobic SBA-15-supported gold-nanoparticle catalyst by using surface passivation, in which the catalytic activity increased more than 14 times for the reduction of nitrobenzene compared with non-passivated SBA-15. In addition, this catalyst can selectively catalyze hydrophobic molecules under our experimental conditions, owing to its high (almost superhydrophobic) hydrophobic properties.
Chemistry - An Asian Journal 05/2013; 8(5):934-8. · 4.50 Impact Factor
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ABSTRACT: In this study, a novel approach was developed for sulfate - containing wastewater treatment via dosing FeO in a two - stage anaerobic reactor (A1, S1). The addition of FeO in its second stage i.e. acidogenic sulfate-reducing reactor (S1) resulted in microbial reduction of Fe (III), which significantly enhanced the biological sulfate reduction. In reactor S1, increasing influent sulfate concentration to 1400 mg/L resulted in a higher COD removal (27.3%) and sulfate reduction (57.9%). In the reference reactor without using FeO (S2), the COD and sulfate removal were 15.6% and 29%, respectively. The combined performance of the two-stage anaerobic reactor (A1, S1) also showed a higher COD removal of 74.2%. Denaturing gradient gel electrophoresis (DGGE) and phylogenetic analysis showed that the dominant bacteria with high similarity to IRB species as well as sulfate reducer Desulfovibrio and acidogenic bacteria (AB) were enriched in S1. Quantitative Polymerase Chain Reaction (qPCR) analysis presented a higher proportion of sulfate reducer Desulfovibrio marrakechensis and Fe (III) reducer Iron-reducing bacteria HN54 in S1.
Water Research 04/2013; 47(6):2033-40. · 4.86 Impact Factor
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ABSTRACT: Microbial electrolysis cell (MEC) devices are efficient for wastewater treatment, but its application was limited due to low anode oxidation rate. The objective of this study was to improve anode performance of a MEC combined anaerobic reactor (R1) for high concentration industrial wastewater treatment via dosing Fe(OH)3. For the first 53days without power, the addition of Fe(OH)3 in R1 enhanced the degradation of reactive brilliant red X-3B dye and sucrose. Applying a voltage of 0.8V in R1 resulted in a higher decolorization and COD removal through driving the redox reactions at electrodes under Fe(III)-reducing conditions. Real-time PCR and enzyme activity analysis showed that the abundance and azoreductase activity of bacteria were improved in R1. Pyrosequencing revealed that dominant populations in anode biofilm and R1 were more diverse and abundant than the common anaerobic reactor (R2), and there was a significant distinction among anode film, R1 and R2 in microbial community structure.
Bioresource technology 03/2013; 136C:273-280. · 4.25 Impact Factor
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ABSTRACT: The anoxic-oxic (A/O) process has been extensively applied for simultaneous removal of organic contaminants and nitrogen in wastewater treatment. However, very little is known about its ability to remove toxic materials. Municipal wastewater contains various kinds of pollutants, some of which have recalcitrant genotoxicity and may cause potential threat to environment, and even can lead to extinction of many species. In this study, we have selected three municipal wastewater treatment plants (WWTPs) employing anoxic-oxic (A/O) process to evaluate their ability to remove acute toxicity and genotoxicity of wastewater. Mortality rate of zebrafish (Danio rerio) was used to evaluate acute toxicity, while micronucleus (MN) and comet assays were used to detect genotoxicity. Results showed that in this process the acute toxicity was completely removed as the treatment proceeded along with decrease in chemical oxygen demand (COD) (<50mgL(-1)) in the effluent. However, in these treatment processes the genotoxicity was not significantly reduced, but an increase in genotoxicity was observed. Both MN and comet assays showed similar results. The eliminated effluent may pose genotoxic threaten although its COD level has met the Chinese Sewage Discharge Standard. This study suggests that further treatment of the wastewater is required after the A/O process to remove the genotoxicity and minimize the ecotoxicological risk.
Chemosphere 12/2012; · 3.21 Impact Factor
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ABSTRACT: Perfluorooctane sulfonate (PFOS) is a highly persistent organic pollutant which has raised many concerns in recent years. Research focusing on plant uptake of PFOS is very necessary when considering its risk of transfer from soil into food chain. In this work, the uptake of PFOS by wheat (Triticum aestivum L.) which is the most main food crop in northern China, was studied. To predict the kinetic uptake limit, the partition-dominated equilibrium sorption of PFOS by roots of wheat was determined. The uptake of PFOS from water at a fixed concentration (1μgmL(-1)) increased with exposure time in approach to steady states and the observed uptake was lower than its limit, due presumably to the PFOS dissipation in wheat. The influences of the environmental factors on plant uptake of PFOS were investigated. The concentrations of PFOS measured in the plant compartments increased with increasing salinity (0.03-7.25psu), temperature (20-30°C) and concentration (0.1-100mgL(-1)) at the ranges tested, whereas the maximum uptake of PFOS was found at pH=6 with increasing pH from 4 to 10. In addition, in all of the cases, the average levels of PFOS detected in the roots were higher than those in the shoots.
Chemosphere 12/2012; · 3.21 Impact Factor
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ABSTRACT: Cobalt leaching from lithium cobalt oxide is a promising reduction process for recovery of cobalt and recycle of spent lithium ion batteries, but suffers from consumption of large amount of reductants and energy, and generation of excess secondary polluted sludge. Thus, effective and environmental friendly processes are needed to improve the existing process limitations. Here we reported microbial fuel cells (MFCs) to effectively reduce Co(III) in lithium cobalt oxide with concomitant energy generation. There was a synergetic interaction in MFCs, leading to a more rapid Co(III) leaching at a rate 3.4 times the sum of rates by conventional chemical processes and no-acid controls. External resistor, solid/liquid ratio, solution conductivity, pH and temperature affected system performance. This study provides a new process for recovery of cobalt and recycle of spent lithium ion batteries with concomitant energy generation from MFCs.
Bioresource technology 11/2012; 128C:539-546. · 4.25 Impact Factor
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ABSTRACT: In this study, novel molecularly imprinted polymer nanoparticles (nanoMCN@MIPs) were prepared by covalent grafting of ofloxacin-imprinted polymer onto the surface of mesoporous carbon nanoparticles (MCNs). SEM analyses indicated that the prepared nanoMCN@MIPs were almost uniform, and their geometrical mean diameter was about 230nm. The sorption behaviors of the nanoMCN@MIPs including sorption kinetics and isotherms, effect of pH, ionic strength, and cross-reactivity were investigated in detail. The adsorption capacity of the nanoparticles for ofloxacin was 40.98mg/g, with a selectivity factor of 2.6 compared to the nonimprinted polymer nanoparticles (nanoMCN@NIPs). The feasibility of removing fluoroquinolone antibiotics (FQs) from environmental waters with the nanoMCN@MIPs was demonstrated using sea water spiked with six typical FQs (ofloxacin, gatifloxacin, balofloxcacin, enrofloxacin, norfloxacin and sarafloxacin). The nanoMCN@MIPs could be reused at least five times with removal efficiency more than 90% except for norfloxacin.
Journal of hazardous materials 11/2012; · 4.14 Impact Factor
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ABSTRACT: Herein we reported the assembly of colloidal graphene (CG) and MC-LR-DNA bioconjugates to develop a homogenous competitive fluorescence-based immunoassay for rapid and sensitive detection of MC-LR in water samples. Initially, the MC-LR-DNA probe was quickly adsorbed onto the CG surface through the strong noncovalent π-π stacking interactions, and can be effectively quenched benefiting from the high quenching efficiency of CG. In contrast, the competitive binding of anti-MC-LR with MC-LR-DNA destroyed the graphene/MC-LR-DNA interaction, thus resulting in the restoration of fluorescence signal. This signal transduction mechanism made it possible for analysis of the target MC-LR. Taking advantage of the colloidal nature of the as-prepared graphene, the assay was carried out in homogeneous solution throughout, which avoided numerous immobilization, incubation and washing steps that were necessary to traditional heterogeneous immunoassays, thereby reducing the whole assay time (within less than 35 min) and allowing a much better antigen-antibody interaction. Moreover, due to the direct competitive mode, the assay did not involve any antibody labeling or modification process, which would be beneficial to preserve the binding affinity of antigen-antibody. Under optimal conditions, the proposed immunosensor can be applied for quantitative analysis of MC-LR with a detection limit of 0.14 μg/L, which satisfied the WHO provisional guideline limit of 1 μg/L for MC-LR in drinking water, thus providing a powerful tool for rapid and sensitive monitoring of MC-LR in environmental samples.
Environmental Science & Technology 10/2012; · 4.80 Impact Factor
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ABSTRACT: We provide a novel and versatile signaling transduction strategy in the fluoroimmunoassay through regulating the interaction between graphene (Gr) and graphene quantum dots (GQDs), and demonstrate its feasibility in sensitive detection of human immunoglobulin G (IgG).
Chemical Communications 10/2012; · 6.17 Impact Factor
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ABSTRACT: A graphene-based immunosensor was fabricated for the detection of microcystin-LR using a horseradish peroxidase-carbon nanosphere-antibody system for signal amplification. Graphene and chitosan were used as immobilization materials to improve the electrochemical performance of the electrode. Signal amplification was achieved using multienzyme functionalized carbon nanosphere. This approach provided a linear range from 0.05 to 15μgL(-1) microcystin-LR with a detection limit of 0.016μgL(-1). Analytical detection of microcystin-LR in environmental water samples were demonstrated by comparing the results obtained using immunosensor and high-performance liquid chromatography. This electrochemical immunosensor showed good performance with high sensitivity, acceptable stability, repeatability and the potential for use in routine water quality monitoring for various toxins.
Colloids and surfaces. B, Biointerfaces 10/2012; 103C:38-44. · 2.60 Impact Factor
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ABSTRACT: Proteomic analysis allows detection of changes of proteins expression in organisms exposed to environmental pollutants, leading to the discovery of biomarkers of exposure and understanding of the action mechanism of toxicity. In the present study, we applied iTRAQ labeling quantitative proteomic technology for global characterization of the liver proteome in mice exposed to perfluorooctane sulfonate (PFOS). This successfully identified and quantified 1038 unique proteins. Seventy-one proteins showed a significant expression change in the treated groups (1.0, 2.5, 5.0 mg/kg of body weight) compared with the control group, and 16 proteins displayed strong dose-dependent changes. Gene ontology analysis showed that these differential proteins were significantly enriched and mainly involved in lipid metabolism, transport, biosynthetic processes, and response to stimulus. We detected significantly increased expression levels of enzymes regulating peroxisomal β-oxidation-including long-chain acyl-CoA synthetase, acyl-CoA oxidase 1, bifunctional enzyme, and 3-ketoacyl-CoA thiolase A. PFOS also significantly induced cytochrome P450s and glutathione S-transferases that are responsible for the metabolism of xenobiotic compounds. The expressions of several proteins with important biological functions-such as cysteine sulfinic acid decarboxylase, aldehyde dehydrogenase, and apolipoprotein A-I, also correlated with PFOS exposure. Together, the present results provide insight into the molecular mechanism and biomarkers for PFOS-induced effects.
Environmental Science & Technology 10/2012; · 4.80 Impact Factor
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ABSTRACT: Azo dye wastewater treatment was enhanced in an acidogenic reactor (A1) by Fe(0) dosing. Both COD (50%) and color (60%) removal in A1 were stable when the dye concentrations were increased from 200 to 800 mg/L. However, the performances of a Fe(0)-free control reactor (A2) showed low COD (34%) and color (32%) removals. The reason was attributed that Fe(0) dosing enhanced the activity of fermentative bacteria, which played an important role in acidogenesis and decolorization. The methanogenic reactor fed with the effluent of A1 exhibited higher removal efficiency and treatment stability. These results suggested that Fe(0) powder dosing was helpful to improve acidogenesis and decolorization to create a favorable feeding condition for the subsequent methanogenic treatment.
Bioresource technology 07/2012; 121:148-53. · 4.25 Impact Factor
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ABSTRACT: An energetic TiN cathode was fabricated for effective electrocatalytic debromination of 2,2',4,4'-tetrabromodiphenyl ethers (BDE-47); this was achieved by placing Ti foils in an aqueous suspension of TiN nanoparticles, then drying the system at 50 °C for 12 h. TEM and SEM characterization showed that the TiN nanoparticles-whose average size was approximately 50 nm-were ideal nano-cubic structures and distributed uniformly on the Ti substrate. When applied as a cathode in cyclic voltammetry measurements, the TiN electrode exhibited stable electrochemical performance over 20 cycles, in the ∼1-10 pH range. The overpotential of the TiN cathode for electrochemical reduction of water (the main side reaction during the electrocatalytic reduction of pollutants in aqueous solution) was determined as 0.54 V, which was much higher than the values for either a Pt wafer (0.12 V), or a Pt film (0.07 V). The TiN electrodes displayed superior electrocatalytic activity for the electrocatalytic debromination of BDE-47. The kinetic constant of BDE-47 degradation on TiN cathode is 0.65 h(-1), which was 2, 4 and 17 times as much as those on Pt film, Pt wafer and graphite cathodes, respectively. A pathway was proposed for the degradation of BDE-47, based on measurements of the intermediate products resulting from the removal of BDE-47 by GC-MS.
Journal of hazardous materials 06/2012; 231-232:105-13. · 4.14 Impact Factor
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ABSTRACT: Combined effects of enrichment procedure and non-fermentable acetate or fermentable glucose on system performance and bacterial community for pentachlorophenol (PCP) degradation in microbial fuel cells (MFCs) were determined in this study. Co-substrate and PCP were added into MFCs either simultaneously or sequentially. Simultaneous addition with glucose (simultaneous-glucose) achieved the shortest acclimation time and the most endurance to heavy PCP shock loads. Species of Alphaproteobacteria (simultaneous-acetate, 33.9%; sequential-acetate, 31.3%), Gammaproteobacteria (simultaneous-glucose, 44.1%) and Firmicutes (sequential-glucose, 31.8%) dominated the complex systems. The genus Sedimentibacter was found to exist in all the cases whereas Spirochaetes were merely developed in simultaneous-acetate and simultaneous-glucose. While Epsilonproteobacteria were only absent from sequential-acetate, simultaneous-glucose benefited to the evolution of Lentisphaerae. These results demonstrate simultaneous-glucose is a strategy for efficient system performance and the microbiological evidence can contribute to improving understanding of and optimizing PCP degradation in MFCs.
Bioresource technology 06/2012; 120:120-6. · 4.25 Impact Factor
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ABSTRACT: A synergistic graphene-based catalyst was engineered by the in situ growth of "naked" Au-nanoparticles (NPs) on graphene sheets. The catalyst exhibits excellent switchable peroxidase-like activity in response to specific DNA.
Chemical Communications 06/2012; 48(56):7055-7. · 6.17 Impact Factor
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ABSTRACT: In this study, an electrochemically enhanced solid-phase microextraction (EE-SPME) approach based on molecularly imprinted polypyrrole/multi-walled carbon nanotubes (MIPPy/MWCNTs) composite coating on Pt wire was developed for selective extraction of fluoroquinolone antibiotics (FQs) in aqueous samples. During the extraction, a direct current potential was applied to the MIPPy/MWCNTs/Pt fiber as working electrode in a standard three-electrode system, FQ ions suffered electrophoretic transfer to the coating surface and then entered into the shape-complimentary cavities by hydrogen-bonding and ion-exchange interactions. After EE-SPME extraction, the fiber was desorbed with desorption solvent for high-performance liquid chromatography (HPLC) analysis. Some parameters influencing EE-SPME extraction such as applied potential, extraction time, solution pH, ionic strength, and desorption solvent were optimized. EE-SPME showed good selectivity and higher extraction efficiency to FQs compared with that of traditional solid-phase microextraction. EE-SPME coupled with HPLC to determine FQs in water samples, the limits of detection (S/N=3) for the selected FQs are 0.5-1.9 μg L(-1). The proposed method was successfully used to the analysis of FQs spiked urine and soil samples, with recoveries of 85.1-94.2% for the urine samples and 89.8-95.5% for the soil samples.
Analytica chimica acta 05/2012; 727:26-33. · 4.31 Impact Factor
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ABSTRACT: In order to investigate the contribution of various black carbon (BC) contents to nonlinearity of sorption and desorption
isotherms for acetochlor on sediment, equilibrium sorption and desorption isotherms were determined to measure sorption and
desorption of acetochlor in sediment amended with various amounts of BC. In this paper, two types of BC referred to as BC400
and BC500 were prepared at 400°C and 500°C, respectively. Higher preparation temperature facilitated the formation of micropores
on BC to enhance its sorption capacity. Increase of the BC content obviously increased the sorption amount and reduced the
desorption amount for acetochlor. When the BC500 contents in total organic carbon (TOC) increased from 0 to 60%, Freundlich
sorption coefficient (K
f) increased from 4.07 to 35.74, and desorption hysteresis became gradually obvious.When the content of BC in TOC was lower
than 23%, the sorption isotherm had a significant linear correlation (p = 50.05). In case of desorption, a significant nonlinear change could be observed when the content of BC was up to 13%. Increase
of BC content in the sediment would result in shifting the sorption-desorption isotherms from linearity to nonlinearity, which
indicated that contribution of BC to nonlinear adsorption fraction became gradually remarkable.
Frontiers of Environmental Science & Engineering in China 04/2012; 3(1):69-74. · 0.75 Impact Factor
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ABSTRACT: Waste gases from oil refining wastewater treatment plants are often characterized by the presence of multicomponent and various
concentrations of compounds. An evaluation of the performance and feasibility of removing multicomponent volatile organic
compounds (VOCs) in off-gases from oil refining wastewater treatment plants was conducted in a pilot-scale compost-based biofilter
system. This system consists of two identical biofilters packed with compost and polyethylene (PE). This paper investigates
the effects of various concentrations of nonmethane hydrocarbon (NMHC) and empty bed residence time (EBRT) on the removal
efficiency of NMHC. Based on the experimental results and practical applications, an EBRT of 66 s was applied to the biofilter
system. The removal efficiencies of NMHC were within the range of 47%–100%. At an EBRT of 66 s, the average removal efficiency
of benzene, toluene, and xylene were more than 99%, 99%, and 100%, respectively. The results demonstrated that multicomponent
VOCs in off-gases from the oil refining wastewater treatment plant could be successfully removed in the biofilter system,
which may provide useful information concerning the design criteria and operation of full-scale biofilters.
Frontiers of Environmental Science & Engineering in China 04/2012; 3(4):483-491. · 0.75 Impact Factor
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ABSTRACT: Pentachlorophenol (PCP) vertical transportation in soil column during its phototransformation on the soil surface was investigated
using a new designed photoreactor. Three kinds of soils were used to study the effect of soil water and soil properties. In
air-dried sandy loam, no obvious PCP transportation occurred in the soil profile when PCP was phototransformed on the soil
surface. And the average removal of PCP in the whole soil column was close to zero after 48h irradiation. In the moist sandy
loam, PCP in the deeper soil could transport to the soil surface with water evaporation and then be transformed during UV
irradiation, thus the average PCP removal in the whole soil column was improved. When the initial water contents are 9.3 and
19.2%, the average PCP removal in the sandy loam after 48h irradiation accounted to 20.9 and 39.9%, respectively. The improving
of PCP removal induced by soil water was limited in the clay and silt soils where PCP transportation was impeded because of
their higher adsorption capacity. In the silt soil where the initial water content was 19.7%, not only PCP transportation
in the deeper soil but also PCP phototransformation on the surface was inhibited seriously because of the high organic matter
content of 18%.
Water Air and Soil Pollution 04/2012; 189(1):103-112. · 1.63 Impact Factor
