Tight ceramic UF membrane as RO pre-treatment: The role of electrostatic interactions on phosphate rejection

WATER RESEARCH

卷:48

Article

Shang, Ran¹  Verliefde, Arne R. D.^1,2  Hu, Jingyi¹  Zeng, Zheyi¹  Lu, Jie¹  Kemperman, Antoine J. B.³  Deng, Huiping⁴  Nijmeijer, Kitty³  Heijman, Sebastiaan G. J.¹  Rietveld, Luuk C.¹ 

[1] Delft Univ Technol, Fac Civil Engn & Geosci, Dept Sanit Engn, NL-2600 GA Delft, Netherlands

[2] Univ Ghent, Fac Biosci Engn, Particle & Interfacial Technol Grp, B-9000 Ghent, Belgium

[3] Univ Twente, Fac Sci & Technol, MESA Inst Nanotechnol, NL-7500 AE Enschede, Netherlands

[4] Tongji Univ, Minist Educ, Key Lab Yangtze River Water Environm, Shanghai 200092, Peoples R China

关键词: Electrostatic repulsion;    Donnan exclusion;    Tight ultrafiltration;    Phosphate rejection;    Phosphate limitation;    Biofouling;    Ceramic membrane;   

DOI  :  10.1016/j.watres.2013.10.008

来源: Elsevier

【 摘 要 】

Phosphate limitation has been reported as an effective approach to inhibit biofouling in reverse osmosis (RO) systems for water purification. The rejection of dissolved phosphate by negatively charged TiO2 tight ultrafiltration (UF) membranes (1 kDa and 3 kDa) was observed. These membranes can potentially be adopted as an effective process for RO pretreatment in order to constrain biofouling by phosphate limitation. This paper focuses on electrostatic interactions during tight UF filtration. Despite the larger pore size, the 3 kDa ceramic membrane exhibited greater phosphate rejection than the 1 kDa membrane, because the 3 kDa membrane has a greater negative surface charge and thus greater electrostatic repulsion against phosphate. The increase of pH from 6 to 8.5 led to a substantial increase in phosphate rejection by both membranes due to increased electrostatic repulsion. At pH 8.5, the maximum phosphate rejections achieved by the 1 kDa and 3 kDa membrane were 75% and 86%, respectively. A Debye ratio (ratio of the Debye length to the pore radius) is introduced in order to evaluate double layer overlapping in tight UF membranes. Threshold Debye ratios were determined as 2 and 1 for the 1 kDa and 3 kDa membranes, respectively. A Debye ratio below the threshold Debye ratio leads to dramatically decreased phosphate rejection by tight UP membranes. The phosphate rejection by the tight UP, in combination with chemical phosphate removal by coagulation, might accomplish phosphate-limited conditions for biological growth and thus prevent biofouling in the RO systems. (C) 2013 Elsevier Ltd. All rights reserved.

【 授权许可】

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