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Wei Y.,Tongji University | Wei Y.,Changzhou University | Chu H.-Q.,Tongji University | Dong B.-Z.,State Key Laboratory of Pollution Control and Resource Reuse | And 3 more authors.
Desalination | Year: 2011

A new PVDF-TiO2 nanowire hybrid ultrafiltration membrane was prepared via phase inversion by dispersing TiO2 nanowires in PVDF casting solutions. The characteristics of the hybrid membranes, i.e., crystal structure, thermal stability, morphology, hydrophilicity, permeation performance, and mechanical properties, were investigated. Results of X-ray diffraction (XRD), thermal gravitational analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) analysis showed that the interaction existed between TiO2 nanowires and PVDF and the thermal stability of the hybrid membrane had been improved by the addition of TiO2 nanowires. Concurrently, dynamic contact angles indicated that the hydrophilicity of the hybrid membranes was enhanced by the addition of TiO2 nanowires. The effects of the TiO2 nanowires in the PVDF on the permeation properties, membrane strength, and antifouling performance were examined. The experimental results indicated that PVDF-TiO2 nanowire hybrid membranes exhibited significant differences in surface properties and intrinsic properties due to TiO2 nanowires addition. Most importantly, PVDF-TiO2 nanowire hybrid membrane can avoid some of the drawbacks of PVDF-TiO2 nanoparticle hybrid membrane, such as, aggregate and leak out of TiO2 nanoparticles, also declining elongation ratio. © 2011. Source

Liu J.X.,Tongji University | Dong B.Z.,State Key Laboratory of Pollution Control and Resource Reuse | Sheng Y.G.,Tongji University | Wang J.P.,Tongji University
Advanced Materials Research | Year: 2013

The main objective of this study was to investigate foulants in chemical cleaning solutions of membrane(CCSM). Sodium hydroxide (NaOH), sodium hypochlorite (NaOCl), hydrochloric acid(HCl) were used as chemical agents respectively. Hydrophobicity, molecular weight distribution and metal ions of foulants in CCSM were analyzed as the major characters for membrane fouling. Results reveal that alkali cleaning can remove both hydrophobic and hydrophilic fractions of natural organic matters(NOM), and acid cleaning mainly removes hydrophilic organic matters. Medium molecular weight of very hydrophobic acids (1-10 kDa) and different molecular weight of neutral hydrophilic acids (100-1000 Da & >300kDa) in NOM can lead to membrane irreversible fouling. Acid cleaning is relatively effective for the reduction of inorganic foulants. The main metal ions in acid cleaning solutions are K,Ca, Al and Mn, which are responsible for membrane inorganic fouling. © (2013) Trans Tech Publications, Switzerland. Source

Ling L.,State Key Laboratory of Pollution Control and Resource Reuse | Ling L.,Tongji University | Pan B.,State Key Laboratory of Pollution Control and Resource Reuse | Pan B.,Nanjing University | And 2 more authors.
Water Research | Year: 2015

Increasing evidences suggest that nanoscale zero-valent iron (nZVI) is an effective agent for treatment and removal of selenium from water. For example, 1.3mM selenite was quickly removed from water within 3min with 5g/L nZVI. In this work, reaction mechanisms of selenite [Se(IV)] in a single core-shell structured nanoscale zero-valent iron (nZVI) particle were studied with the method of spherical aberration corrected scanning transmission electron microscopy (Cs-STEM) integrated with X-ray energy dispersive spectroscopy (XEDS). This method was utilized to visualize solid phase translocation and transformation of Se(IV) such as diffusion, reduction, deposition and the effect of surface defects in a single nanoparticle. Se(IV) was reduced to Se(-II) and Se(0), which then formed a 0.5nm layer of selenium at the iron oxide-Fe(0) interface at a depth of 6nm from the surface. The results provided near atomic-resolution proof on the intraparticle diffusion-reduction of Se(IV) induced by nZVI. The STEM mapping also discovered that defects on the surface layer accelerate the diffusion of selenium and increase the capacity of nZVI for selenium sequestration. © 2015 Elsevier Ltd. Source

Li B.,State Key Laboratory of Pollution Control and Resource Reuse | Liu F.,State Key Laboratory of Pollution Control and Resource Reuse | Wang J.,State Key Laboratory of Pollution Control and Resource Reuse | Ling C.,State Key Laboratory of Pollution Control and Resource Reuse | And 4 more authors.
Chemical Engineering Journal | Year: 2012

The high selectivity for the separation of nickel from cobalt-solution by a polyamine chelating resin was explored. As to the sole-component static system, the equilibrium data could be satisfactorily described by the Langmuir isotherm, from which the calculated maximum adsorption capacities for Ni(II) and Co(II) were 0.982. mmol/g and 0.741. mmol/g, respectively. Additionally, in the binary system with high concentration ratio of cobalt and nickel, the uptake amount of resin for both ions decreased, indicating their competitive adsorption behavior on active sites. Separation factors suggested the extremely higher selectivity for Ni(II) against Co(II). The obtained separation factor values indicated the extremely higher selectivity for Ni(II) versus Co(II). The column dynamic breakthrough curves revealed a potential success for the achievement of high-purity cobalt because of the higher initial adsorption rate and capacity toward Ni(II). © 2012 Elsevier B.V. Source

Cheng C.,Nanjing University | Wang J.-N.,Nanjing University | Wang J.-N.,State Key Laboratory of Pollution Control and Resource Reuse | Yang X.,State Key Laboratory of Pollution Control and Resource Reuse
Chinese Chemical Letters | Year: 2013

The novel chelating sponge modified with hydroxamic acid groups was prepared by a grafting polymerization followed by a nucleophilic substitution reaction. Elementary analysis, SEM, FT-IR spectroscopy and XPS were used to characterize the spongy adsorbent (PVA-MA-HH). Adsorption isotherm study indicated that PVA-MA-HH had high equilibrium adsorption capacity for Cu 2+. © 2013 Jin-Nan Wang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved. Source

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