Tianjin Key Laboratory of Membrane Science and Desalination Technology

Tianjin, China

Tianjin Key Laboratory of Membrane Science and Desalination Technology

Tianjin, China
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Xu L.,Tianjin University | Xu L.,Tianjin Key Laboratory of Membrane Science and Desalination Technology | Liang G.,Tianjin University | Liang G.,Tianjin Key Laboratory of Membrane Science and Desalination Technology | And 2 more authors.
Chemosphere | Year: 2017

A distinctive SnO2[sbnd]Sb electrode with highly ordered Nb doped TiO2 nanotubes sheet as a new substrate, obtained by Nb[sbnd]Ti alloy anodization, is prepared by pulse electrochemical deposition for the first time as electrocatalytic oxidation anode for wastewater treatment. The novel electrode has a larger surface area and smaller crystallite particles than conventional SnO2[sbnd]Sb electrodes as obtained from the analysis of scanning electron microscopy and X-ray diffraction. Compared with Ti/SnO2[sbnd]Sb and Ti/TiO2-NTs/SnO2[sbnd]Sb prepared by pulse electrochemical deposition, the electrode modified by Nb[sbnd]TiO2-NTs has the higher oxygen evolution potential of 2.29 V (vs. Ag/AgCl), and the lower charge transfer resistance, which decreased by 65% and 79%. The service lifetime of Nb[sbnd]Ti/Nb[sbnd]TiO2-NTs/SnO2[sbnd]Sb is 4.9 times longer than that of Ti/SnO2[sbnd]Sb and 1.9 times longer than that of Ti/TiO2-NTs/SnO2[sbnd]Sb. The new electrode is proved to have an excellent electrochemical oxidation and degradation ability using Acid Red 73 as a target organic pollutant. The AR 73 removal, chemical oxygen demand removal and kinetic rate constant are increased obviously due to the introduction of Nb[sbnd]TiO2-NTs. Besides, the energy consumption reduces 37.2% and 31.4% in contrast with Ti/SnO2[sbnd]Sb and Ti/TiO2-NTs/SnO2[sbnd]Sb. Hence, the Ti/SnO2[sbnd]Sb modified by Nb[sbnd]TiO2-NTs is a very promising anode material for the electrochemical treatment of dye wastewater. © 2017 Elsevier Ltd


Xu L.,Tianjin University | Xu L.,Tianjin Key Laboratory of Membrane Science and Desalination Technology | Guo Z.,Tianjin University | Guo Z.,Tianjin Key Laboratory of Membrane Science and Desalination Technology | And 2 more authors.
Electrochimica Acta | Year: 2013

This work is conducted to study ability of anodic oxidation treatment azo dye C.I. Acid Red 73 (AR73) using the electrodes of Y doped Ti/SnO 2-Sb electrodes prepared by thermal decomposition and Ti/SnO 2-Sb electrodes prepared by electrodeposition. It has been shown that doping Y can enhances the electrochemical activity of the electrodes, but the accelerated service life was slightly reduced. Both the lifetime and electrochemical activity of Ti/SnO2-Sb electrodes prepared by electrodeposition in a new Sn-Sb electrodeposition bath outperform the Ti/SnO2-Sb electrodes prepared by thermal decomposition. Moreover, the effect of varying wastewater process indexes (initial pH (4-10), the addition of NaCl (0-9 mM) and initial dye concentration (0.5-2.0 g L -1)) on the performance of anodic oxidation using Ti/SnO 2-Sb electrodes prepared by electrodeposition was investigated followed by the performance indicators analyses including color, chemical oxygen demand (COD), current efficiency and specific energy consumption. Finally, the synergy technology of anodic oxidation coupling nanofiltration was adopted to treat AR73 wastewater in order to overcome the low current efficiency of anodic oxidation. Preliminary results have shown that the synergy technology could cost-effectively treat AR73 wastewater. © 2013 Elsevier Ltd.


Xie L.,Tianjin University | Xie L.,Tianjin Key Laboratory of Membrane Science and Desalination Technology | Chen X.,Tianjin University | Chen X.,Tianjin Key Laboratory of Membrane Science and Desalination Technology
Huagong Xuebao/CIESC Journal | Year: 2014

Spinel-type manganese oxide Li1.6Mn1.6O4 was prepared. It was mixed with poly(vinylidene fluoride) (PVDF) and flat membrane was obtained for recovering lithium from lithium-containing waters by a solvent exchange method. After the membrane was treated with an HCl solution it can uptake lithium. A series of experiments for examining its adsorption and reuse were carried out. Results showed that when membrane M-10-55[Li] was treated with 0.5 mol·L-1 HCl solution for 2 h, the lithium extraction reached equilibrium and about 95% lithium was extracted, and the rate of manganese dissolution was about 3.5%. The membrane M-10-55[H] obtained showed good performance in adsorption capacity to Li+ (about 41 mg·g-1), and when used for the fifth time it still had an adsorption capacity of 35 mg·g-1. The membrane can selectively adsorb Li+ better compared with Na+, K+, Mg2+ and Ca2+. It is potential to be used in enrichment and recovery of lithium from seawater and other liquid lithium sources. © All Rights Reserved.


Zhang L.,Tianjin University | Zhang L.,Tianjin Key Laboratory of Membrane Science and Desalination Technology | Xu L.,Tianjin University | Xu L.,Tianjin Key Laboratory of Membrane Science and Desalination Technology | And 2 more authors.
Electrochimica Acta | Year: 2014

A new type of Ti/SnO2-Sb electrode modified with carbon nanotube (CNT) has been fabricated using a pulse electrodeposition method. The electrode modified with CNT versus without CNT has larger surface area and smaller crystallite particles (41.9 nm versus 46.8 nm) as seen by scanning electron microscopy (SEM), and calculated through X-ray diffraction (XRD), respectively. It means that the CNT-modified electrode can provide more active sites for electrochemical oxidation of organic pollutants. Oxygen evolution potential of the CNT-modified electrode has 0.07 V higher overpotential in the Linear sweep voltammetry (LSV) curve. The service lifetime of Ti/SnO2-Sb-CNT electrode is 4.8 times longer than that of the Ti/SnO2-Sb electrode without CNT modifying. The Ti/SnO2-Sb-CNT electrode is demonstrated to have a superior electrochemical oxidation and degradation abilities using Acid Red 73 (AR 73) as a model organic pollutant. The CNT-modified electrode has higher kinetic rate constant, chemical oxygen demand (COD) and total organic carbon (TOC) removals, and mineralization current efficiency, which is 1.93, 1.27, 1.26, and 1.38 times those of the Ti/SnO2-Sb electrode, respectively. The repeated experiments prove the reproducibility of the data. Ti/SnO2-Sb-CNT electrode is 1.15 times more effective in permeation flux than the Ti/SnO2-Sb electrode when combining electro-catalytic oxidation and nanofiltration for treating dye wastewater. © 2013 Elsevier Ltd.


Xu L.,Tianjin University | Xu L.,Tianjin Key Laboratory of Membrane Science and Desalination Technology | Sun Y.,Tianjin University | Sun Y.,Tianjin Key Laboratory of Membrane Science and Desalination Technology | And 2 more authors.
Desalination | Year: 2014

Electro-catalytic oxidation enhanced cross-flow nanofiltration system has been carried out to treat tetracycline hydrochloride wastewater, using Ti/SnO2-Sb anodes prepared by the method of pulse electrodeposited and the membrane of NF90 in the laboratory-scale membrane module. The effects of electro-catalytic oxidation for controlling the fouling of the membrane and concentration polarization were studied in the present paper. Flux change and filtration resistance were studied in order to characterize weakening the concentration polarization and membrane fouling by the introduction of electro-catalytic oxidation. A comparative study between classic nanofiltration and coupling process was then performed at different operating conditions including current density, operating pressure, cross flow velocity and the initial feed concentration. Experimental results showed that electro-catalytic oxidation could reduce the resistance of concentration polarization and cake layer. The filtration rate was found to increase with the increasing in current density and transmembrane pressure. It was no response that did the filtration rate has on the cross flow velocity due to a thin layer of concentration polarization, which was caused by the introduction of electro-catalytic oxidation. Permeate flux decreased with the increasing in initial feed concentration. Morphological difference of the membrane surface between the two processes was studied by a scanning electron microscope. © 2014 Elsevier B.V.


Xu L.,Tianjin University | Xu L.,Tianjin Key Laboratory of Membrane Science and Desalination Technology | Zhang L.,Tianjin University | Zhang L.,Tianjin Key Laboratory of Membrane Science and Desalination Technology | And 2 more authors.
Journal of Membrane Science | Year: 2014

The research was conducted to study the independent impact of electro-catalytic oxidation on the nanofiltration (NF) performance during the separation of C.I. Acid Red 73 (AR 73) wastewater. Ti/SnO2-Sb2O3 electrode modified with rare element yttrium (Y) was successfully prepared by the sol-gel technology, and then it was used as an anode for the degradation of azo dye AR 73 coupling with NF. The electro-catalytic oxidation could be restrained by painting insulating varnish on the surface of anode. Through comparing the permeation flux with the case of not using insulating varnish, we could identify the independent impact of electro-catalytic oxidation in the coupling process. The influence of operating parameters, e.g., applied voltage, initial feed concentration, operating pressure and cross flow velocity on the electro-catalytic oxidation flux and energy consumption was investigated respectively. The results indicated that the accelerated lifetime of the Ti/SnO2-Sb2O3-Y electrode reached 4.1h, which was 9.1 times longer than that of the Ti/SnO2-Sb2O3 electrode, and the electro-catalytic oxidation flux was enhanced to a great extent by choosing appropriate operating conditions and the coupling process could energy-effectively treat AR 73 wastewater. © 2013 Elsevier B.V.


Zhao Y.,Tianjin University | Jiang Z.,Tianjin University | Xiao L.,Tianjin University | Xu T.,Tianjin University | And 3 more authors.
Solid State Ionics | Year: 2011

Hydroxyapatite (BMHA) particles, using Ca(OH)2 and H 3PO4 as the reactants and chondroitin sulfate as the template/catalyst, are synthesized through a biomimetic mineralization approach. The BMHA particles are then incorporated into chitosan (CS) matrices to prepare the CS/BMHA hybrid membranes. Thermal stability of the hybrid membranes is enhanced owing to the formation of strong hydrogen bonds between the BMHA surface and CS molecules. The methanol crossover of the CS/BMHA membranes is decreased due to their prolonged methanol transfer pathways and the improved hydrophilicity. The hybrid membranes exhibit at most 127% higher proton conductivity than the pure CS membrane because of the high intrinsic proton conductivity of the BMHA particles, the strong hydrophilicity and the large free volume of the membranes. In particular, the hybrid membrane with BMHA content of 8 wt% exhibits1.8 times higher selectivity of proton to methanol than the pure CS membrane. © 2011 Elsevier B.V. All rights reserved.


Zhao Y.,Tianjin University | Zhao Y.,Tianjin Key Laboratory of Membrane Science and Desalination Technology | Wang Y.,Tianjin University | Wang Y.,Tianjin Key Laboratory of Membrane Science and Desalination Technology | And 8 more authors.
Desalination | Year: 2013

In this paper, graphite cloths were used as electrode materials to fabricate the capacitive deionization (CDI) cell and the ion-exchange membranes were introduced in the CDI cell to assemble the membrane capacitive deionization (MCDI) module. The desalination performances of the MCDI and the CDI cells were investigated under different working voltages and feed concentrations and assessed by adsorption capacity and specific energy consumption. The experimental results indicated that the introduction of the ion exchange membranes could effectively prevent the "co-ion" effect in the CDI and the current efficiency of MCDI was up to four times of the CDI. Under the experimental conditions, the adsorption capacity of MCDI is much higher than that of the CDI and also its specific energy consumption was dramatically reduced indicating the comprehensive economical advantage of MCDI technology. © 2013 Elsevier B.V.


Zhang J.,Tianjin University | He Z.,Tianjin University | Li W.,Tianjin University | Han Y.,Tianjin Key Laboratory of Membrane Science and Desalination Technology
RSC Advances | Year: 2012

The deactivation mechanism of AuCl 3 catalyst in the reaction of acetylene hydrochlorination was studied by using AuCl 3 dimer model and the density functional theory (DFT) method. Four possible paths for the acetylene hydrochlorination reaction catalyzed by AuCl 3 were illustrated with corresponding transition states. The activation free energies and reaction rate constants of the four paths were also analyzed. It is apparent that when HCl and C 2H 2 coadsorbed on the AuCl 3 dimer, the C 2H 2 was co-catalyzed by HCl and the AuCl 3 dimer to produce C 2H 3Cl and the reaction energy barrier was as low as 23.35 kcal mol -1. If the HCl in the gas phase could not adsorb on the Au site within the set time, the intermediate chlorovinyl was difficult to desorb from the AuCl 3 catalyst as its desorption energy was as high as 41.336 kcal mol -1. As the reaction temperature increased, C 2H 2 became easier to be adsorbed on the AuCl 3 catalyst prior to HCl, which resulted in the side reaction and the rapid deactivation of the AuCl 3 dimer due to the loss of Cl atoms. Our calculations are necessary for us to clearly understand the experimental results, which indicate a great dependence of activity and stability of AuCl 3 catalysts on the HCl:C 2H 2 ratio as well as the temperature. © 2012 The Royal Society of Chemistry.


Xu L.,Tianjin University | Xu L.,Tianjin Key Laboratory of Membrane Science and Desalination Technology | Du L.-S.,Tianjin University | Du L.-S.,Tianjin Key Laboratory of Membrane Science and Desalination Technology | And 2 more authors.
Journal of Membrane Science | Year: 2012

To investigate the effects of electrolytic oxidation on nanofiltration in treating dye waste water, we put a mesh catalytic electrode on the intercept side of the membrane and apply a voltage to realize the coupling of electrolytic oxidation and nanofiltration. The effects of the electroosmosis, electrophoresis and electrochemical oxidation on the flux were investigated. Experiments show that electroosmosis makes the flux increase linearly with the electric intensity. When there is only an electric filed in the coupling experiments, we get that, with the increase of the electric intensity the flux is accelerating until the electric intensity reach the critical value, after that the flux increase linearly with the electric intensity. With the current density increasing, the degraded organics and the bubbles generated increase, and so the thickness of the concentration polarization and gel layer is reduced in a certain degree. The flux increases with the decrease of the feed concentration in the coupling experiments. The trend that the flux increases with the pressure slows down. The flux increases to a certain value and then keeps constant with the increase of the cross flow velocity. The trend that the flux decreases with time slows down with the increase of the voltage, because of the electroosmosis, electrophoresis and electrochemical oxidation. And when the voltage increases to a certain degree, the flux keeps at a high level and changes less with time because the thickness of concentration polarization and gel layer is reduced to the minimum. © 2012 Elsevier B.V.

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