Please use this identifier to cite or link to this item: https://hdl.handle.net/10356/96457
Title: Effects of hypochlorous acid exposure on the rejection of salt, polyethylene glycols, boron and arsenic(V) by nanofiltration and reverse osmosis membranes
Authors: Do, Van Thanh
Tang, Chuyang Y.
Reinhard, Martin
Leckie, James O.
Issue Date: 2012
Source: Do, V. T., Tang, C. Y., Reinhard, M., & Leckie, J. O. (2012). Effects of hypochlorous acid exposure on the rejection of salt, polyethylene glycols, boron and arsenic(V) by nanofiltration and reverse osmosis membranes. Water Research, 46(16), 5217-5223.
Series/Report no.: Water research
Abstract: The separation layer of polyamide-based (PA) thin film composite (TFC) membranes can be modified by active chlorine species. The PA-TFC membranes, NF90, BW30 and NF270, were exposed to different concentrations of sodium hypochlorite (NaOCl) at pH 5 for 24 h. Elemental composition obtained from X-ray Photoelectron Spectroscopy (XPS) showed that the chlorine content in the PA layer increased with the chlorine concentrations. Treatment of membranes with 10 ppm Cl increased the membrane hydrophilicity. By contrast, when treated with 1000 ppm Cl or more, the membranes became less hydrophilic. Water permeability values for all 3 membrane types declined with increased chlorine concentrations. Filtration of polyethylene glycols (PEGs) with molecular weights of 200, 400 and 600 Daltons (Da) was performed to investigate the influence of chlorine treatment on membrane molecular weight cut off (MWCO) and rejection by size exclusion. Treatment with 10 and 100 ppm Cl lowered the MWCO while treatment with higher concentrations increased the MWCO. All chlorinated membranes experienced higher NaCl rejection compared to virgin ones. The performance of NF90 was tested with respect to the rejection of inorganic contaminants including boron (H3BO3) and arsenic (H2AsO4−). The boron rejection results paralleled PEG rejection whereas those for arsenic followed NaCl rejection patterns. The changes in membrane performance due to chlorine treatment were explained in terms of competing mechanisms: membrane tightening, bond cleavage by N-chlorination and chlorination promoted polyamide hydrolysis.
URI: https://hdl.handle.net/10356/96457
http://hdl.handle.net/10220/10252
ISSN: 0043-1354
DOI: 10.1016/j.watres.2012.06.044
Rights: © 2012 Elsevier Ltd.
Fulltext Permission: none
Fulltext Availability: No Fulltext
Appears in Collections:CEE Journal Articles

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