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Zhao B.,Tianjin Polytechnic University | Zhao B.,State Key Laboratory of Hollow Fiber Membrane Materials and Processes | Zhao B.,Peking University | Zhao B.,Key Laboratory of Water and Sediment science | And 5 more authors.
Journal of Hazardous Materials | Year: 2012

A simple point of use (POU) device based on the theory of Donnan dialysis was developed for the removal of arsenate (As(V)) in the present study. A commercial anion exchange membrane was used as a semipermeable barrier between the feed and stripping solution (As(V)-spiked groundwater and a 12gL -1 table salt solution, respectively). The proposed POU device could be operated 26 times before replacing the stripping solution. In each batch, approximately 80% of the arsenate anions were transported across the membrane within 24h, and the arsenic concentration of the stripping solution was finally more than 180 times greater than that of the treated water. Cations were well preserved in treated water; however, a slight increase in the sodium ion concentration was observed due to electrolyte leakage. Alternatively, the chloride ion concentration significantly increased at the expense of a loss of sulfate and bicarbonate. The quality of treated water was in compliance with drinking water standards. Membrane fouling was investigated, and a reduction in the As(V) removal rates was not observed when the membrane was used repeatedly. Our results showed that the proposed Donnan dialysis POU device could effectively remove arsenic from drinking water in rural areas in a sustainable manner. © 2012 Elsevier B.V.

Xue A.,Peking University | Xue A.,Key Laboratory of Water and Sediment science | Shen Z.-Z.,Peking University | Shen Z.-Z.,Key Laboratory of Water and Sediment science | And 4 more authors.
Journal of Hazardous Materials | Year: 2013

Conventional zerovalent iron (ZVI) technology has low arsenic removal efficiency because of the slow ZVI corrosion rate. In this study, microbial fuel cell (MFC)-zerovalent iron (MFC-ZVI) hybrid process has been constructed and used to remove arsenite (As(III)) from aqueous solutions. Our results indicate that the ZVI corrosion directly utilizes the low-voltage electricity generated by MFC in the hybrid process and both the ZVI corrosion rate and arsenic removal efficiency are therefore substantially increased. The resultant water qualities are compliant with the recommended standards of EPA and WHO. Compared to the ZVI process alone, the H2O2 generation rate and output are dramatically improved in MFC-ZVI hybrid process. Strong oxidants derived from H2O2 can rapidly oxidize As(III) into arsenate (As(V)), which helps to improve the As(III) removal efficiency. The distribution analysis of As and Fe indicates that the As/Fe molar ratio of the flocs in solution is much higher in the MFC-ZVI hybrid process. This phenomenon results from the different arsenic species and hydrous ferric oxides species in these two processes. In addition, the electrosorption effect in the MFC-ZVI hybrid process also contributed to the arsenic removal by concentrating As(V) in the vicinity of the iron electrode. © 2013.

Zhao H.,Peking University | Zhao H.,Key Laboratory of Water and Sediment science | Zhang Y.,Peking University | Zhang Y.,Key Laboratory of Water and Sediment science | And 6 more authors.
Environmental Science and Technology | Year: 2012

Electrochemical reduction of carbon dioxide (CO2) to useful chemical materials is of great significance to the virtuous cycle of CO 2. However, some problems such as high overpotential, high applied voltage, and high energy consumption exist in the course of the conventional electrochemical reduction process. This study presents a new CO2 reduction technique for targeted production of formic acid in a microbial electrolysis cell (MEC) driven by a microbial fuel cell (MFC). The multiwalled carbon nanotubes (MWCNT) and cobalt tetra-amino phthalocyanine (CoTAPc) composite modified electrode was fabricated by the layer-by-layer (LBL) self-assembly technique. The new electrodes significantly decreased the overpotential of CO2 reduction, and as cathode successfully reduced CO2 to formic acid (production rate of up to 21.0 ± 0.2 mg·L-1·h-1) in an MEC driven by a single MFC. Compared with the electrode modified by CoTAPc alone, the MWCNT/CoTAPc composite modified electrode could increase the current and formic acid production rate by approximately 20% and 100%, respectively. The Faraday efficiency for formic acid production depended on the cathode potential. The MWCNT/CoTAPc composite electrode reached the maximum Faraday efficiency at the cathode potential of ca. -0.5 V vs Ag/AgCl. Increasing the number of electrode modification layers favored the current and formic acid production rate. The production of formic acid was stable in the MFC-MEC system after multiple batches of CO2 electrolysis, and no significant change was observed on the performances of the modified electrode. The coupling of the catalytic electrode and the bioelectrochemical system realized the targeted reduction of CO2 in the absence of external energy input, providing a new way for CO2 capture and conversion. © 2012 American Chemical Society.

Wang X.,Tianjin Polytechnic University | Wang J.,Tianjin Polytechnic University | Wu J.,Harbin Institute of Technology | Cheng B.,State Key Laboratory of Hollow Fiber Membrane Materials and Processes | And 2 more authors.
Ionics | Year: 2015

Mg-doped spinel LiMg0.05Mn1.95O4 was synthesized and coated with three types of Li-containing manganese oxides (Li2Mn4O9, Li4Mn5O12, and LiNi0.5Mn1.5O4) to improve the cycling properties at room temperature and at 50 °C via a coprecipitation method. The as-prepared spinels were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), inductively coupled plasma (ICP), and electrochemical tests. The results indicate that all the coated samples show enhanced electrochemical performance including higher initial charge-discharge capacities and more stable cycling properties as well as improved coulombic efficiency. Especially, the LiNi0.5Mn1.5O4-coated sample delivers the highest initial discharge capacity of 129 mAh/g with capacity retention of 82.5 % as well as the best coulombic efficiency of 92.1 %. This improved performance could be attributed to the enhanced electrochemical kinetics by successful surface modification of spinels with Li-containing manganese oxides via coprecipitation method. © 2015, Springer-Verlag Berlin Heidelberg.

Zang H.,Tianjin Polytechnic University | Su Q.,Tianjin Polytechnic University | Guo S.,Tianjin Polytechnic University | Mo Y.,Tianjin Polytechnic University | Cheng B.,State Key Laboratory of Hollow Fiber Membrane Materials and Processes
Chinese Journal of Chemistry | Year: 2011

A new class of pyrazolone derivatives has been isolated in good to excellent yields from the 2 : 1 condensation reaction between 3-methyl-1-phenyl-5-pyrazolone and arylaldehydes in the presence of ionic liquid [HMIM]HSO 4. The compounds were characterised by their IR, NMR spectra, MS and elemental analyses. The important features of the methodology are a wide application range of substrates, higher yields and shorter reaction time. © 2011 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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