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Zhang Y.,Zhejiang Sci-Tech University | Yu C.,Zhejiang Sci-Tech University | Lu Z.,Zhejiang Sci-Tech University | Lu Z.,Hangzhou Tianchuang Environmental Technology Co. | Yu S.,Zhejiang Sci-Tech University
Desalination and Water Treatment | Year: 2015

This study focused on the modification of flat-sheet polysulfone ultrafiltration membranes for nanofiltration (NF) through sequential deposition of poly(vinyl alcohol) (PVA) and sodium carboxymethyl cellulose (CMCNa) with glutaraldehyde cross-linking after each deposition. The contents of PVA and CMCNa in the coating solutions were varied to optimize the membrane performance and the modified membranes were characterized in terms of surface and permeation properties. It was found that the membrane surface became denser, more hydrophilic, and negatively charged at neutral pH after modification and the modified membrane possessed the NF separation characteristic. Under 5.0 bar, the optimized modified membrane exhibited a high-pure water flux of 89.5 l/m2 h and rejections of 37.8 and 93.8% to 500 mg/l NaCl and Na2SO4 aqueous solution, respectively. The modified membrane could also efficiently remove anionic dyes from aqueous solution, showing retentions of 99.7 and 99.5% to methyl blue and congo red, respectively, under neutral pH and 5.0 bar. Additionally, the modified membrane possessed good chlorine stability, and acid and alkaline resistances. The technique developed is potentially applicable for the fabrication of high-flux negatively charged NF membranes for partial desalination and anionic dye removal. © 2015 Balaban Desalination Publications. All rights reserved. Source

Sun J.,Zhejiang Sci-Tech University | Zhang L.,Zhejiang Sci-Tech University | Xie B.,Hangzhou Tianchuang Environmental Technology Co. | Fan L.,Hangzhou Tianchuang Environmental Technology Co. | Yu S.,Zhejiang Sci-Tech University
Desalination and Water Treatment | Year: 2015

Abstract: Separation efficiency and stability of two lab-fabricated polysulfonamide (PSA) and polypiperazineamide (PA) thin-film composite nanofiltration membranes in long-term filtration of copper sulphate and sulphuric acid mixture were evaluated and compared in this study. The PSA and PA membranes were fabricated through interfacial polymerization process and 60-day long-term filtration tests were carried out with an acidic aqueous solution containing 2.5% (w/v) CuSO4 and 8.0% (w/w) H2SO4 under 25.0°C and 10.0 bar. The separation efficiency was studied in terms of permeate flux and retentions to copper and acid. The change of separation efficiency with filtration time was investigated to evaluate the performance stability of the membranes studied. Attenuated total reflectance Fourier transform infrared, field emission scanning electron microscopy, streaming potential analyzer, and contact angle analyzer were also adopted to characterize the change of membrane surface property during filtration. It was found that the PSA membrane maintained its separation efficiency during the 60-day continuous filtration, exhibiting a copper retention of about 83.5% and a sulphuric acid retention of less than 5.0%. The PA membrane began to lose its selectivity after 20 days of filtration due to the deterioration of its skin layer, which was confirmed by the change of membrane surface property. © 2013, © 2013 Balaban Desalination Publications. All rights reserved. Source

Xie B.-M.,Hangzhou Tianchuang Environmental Technology Co. | Wei Y.-F.,Environmental Science Research and Design Institute of Zhejiang Province | Tao J.,Hangzhou Tianchuang Environmental Technology Co. | Qiu H.,Hangzhou Tianchuang Environmental Technology Co. | And 3 more authors.
Chung-kuo Tsao Chih/China Pulp and Paper | Year: 2012

The advanced treatment of concentrated papermaking wastewater from reverse osmosis by Fenton process was studied. Effect of several factors, such as nH 2O 2/nFe 2+, H 2O 2 dosage, Fe 2+ dosage, reaction time and pH on the removal of CODCr was discussed. The results of study showed that under the optimum condition of pH=4, H 2O 2=5 mmol/L, Fe 2+=2.5 mmol/L, CODCr reduced to less than 100 mg/L and the removal ratio was over 60%. Source

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