Role of calcium ions on the removal of haloacetic acids from swimming pool water by nanofiltration: mechanisms and implications

We investigated the removal of haloacetic acids (HAAs) from swimming pool waters (SPWs) by two nanofiltration membranes NF270 and NF90. The strong matrix effect (particularly by Ca2+) on membrane rejection prompts us to systematically investigate the mechanistic role of Ca2+ in HAA rejection. At typ...

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Main Authors: Yang, Linyan, Zhou, Jin, She, Qianhong, Wan, Man Pun, Wang, Rong, Chang, Victor Wei-Chung, Tang, Chuyang Y.
Other Authors: School of Civil and Environmental Engineering
Format: Article
Language:English
Published: 2018
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Online Access:https://hdl.handle.net/10356/88017
http://hdl.handle.net/10220/44515
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-880172020-09-26T21:59:04Z Role of calcium ions on the removal of haloacetic acids from swimming pool water by nanofiltration: mechanisms and implications Yang, Linyan Zhou, Jin She, Qianhong Wan, Man Pun Wang, Rong Chang, Victor Wei-Chung Tang, Chuyang Y. School of Civil and Environmental Engineering School of Mechanical and Aerospace Engineering Interdisciplinary Graduate School (IGS) Residues and Resource Reclamation Centre Nanyang Environment and Water Research Institute Singapore Membrane Technology Centre Haloacetic Acids Membranes We investigated the removal of haloacetic acids (HAAs) from swimming pool waters (SPWs) by two nanofiltration membranes NF270 and NF90. The strong matrix effect (particularly by Ca2+) on membrane rejection prompts us to systematically investigate the mechanistic role of Ca2+ in HAA rejection. At typical SPW pH of 7.5, NF90 maintained consistently high rejection of HAAs (>95%) with little influence by Ca2+, thanks to the dominance of size exclusion effect for this tight membrane (pore radius ∼ 0.31 nm). In contrast, the rejections of both inorganic ions (e.g., Na+ and Cl−) and HAA anions were decreased at higher Ca2+ concentration for NF270 (pore radius ∼ 0.40 nm). Further tests show that the rejection of neutral hydrophilic molecular probes and the membrane pore size were not affected by Ca2+. Although Ca2+ is unable to form strong complex with HAAs, we observed the binding of Ca2+ to NF270 together with a reduction in its surface charge. Therefore, the formation of membrane-Ca2+ complex, which weakens charge interaction effect, was responsible for the reduced HAA rejection. The current study reveals important mechanistic insights of the matrix effect on trace contaminant rejection, which is critical for a better understanding of their fate and removal in membrane-based treatment. Accepted version 2018-03-06T09:00:20Z 2019-12-06T16:54:11Z 2018-03-06T09:00:20Z 2019-12-06T16:54:11Z 2016 Journal Article Yang, L., Zhou, J., She, Q., Wan, M. P., Wang, R., & Chang, V. W.-C. (2016). Role of calcium ions on the removal of haloacetic acids from swimming pool water by nanofiltration: mechanisms and implications. Water Research, 110, 332-341. 0043-1354 https://hdl.handle.net/10356/88017 http://hdl.handle.net/10220/44515 10.1016/j.watres.2016.11.040 en Water Research © 2016 Elsevier Ltd. This is the author created version of a work that has been peer reviewed and accepted for publication by Water Research, Elsevier Ltd. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [http://dx.doi.org/10.1016/j.watres.2016.11.040]. 34 p. application/pdf
institution Nanyang Technological University
building NTU Library
country Singapore
collection DR-NTU
language English
topic Haloacetic Acids
Membranes
spellingShingle Haloacetic Acids
Membranes
Yang, Linyan
Zhou, Jin
She, Qianhong
Wan, Man Pun
Wang, Rong
Chang, Victor Wei-Chung
Tang, Chuyang Y.
Role of calcium ions on the removal of haloacetic acids from swimming pool water by nanofiltration: mechanisms and implications
description We investigated the removal of haloacetic acids (HAAs) from swimming pool waters (SPWs) by two nanofiltration membranes NF270 and NF90. The strong matrix effect (particularly by Ca2+) on membrane rejection prompts us to systematically investigate the mechanistic role of Ca2+ in HAA rejection. At typical SPW pH of 7.5, NF90 maintained consistently high rejection of HAAs (>95%) with little influence by Ca2+, thanks to the dominance of size exclusion effect for this tight membrane (pore radius ∼ 0.31 nm). In contrast, the rejections of both inorganic ions (e.g., Na+ and Cl−) and HAA anions were decreased at higher Ca2+ concentration for NF270 (pore radius ∼ 0.40 nm). Further tests show that the rejection of neutral hydrophilic molecular probes and the membrane pore size were not affected by Ca2+. Although Ca2+ is unable to form strong complex with HAAs, we observed the binding of Ca2+ to NF270 together with a reduction in its surface charge. Therefore, the formation of membrane-Ca2+ complex, which weakens charge interaction effect, was responsible for the reduced HAA rejection. The current study reveals important mechanistic insights of the matrix effect on trace contaminant rejection, which is critical for a better understanding of their fate and removal in membrane-based treatment.
author2 School of Civil and Environmental Engineering
author_facet School of Civil and Environmental Engineering
Yang, Linyan
Zhou, Jin
She, Qianhong
Wan, Man Pun
Wang, Rong
Chang, Victor Wei-Chung
Tang, Chuyang Y.
format Article
author Yang, Linyan
Zhou, Jin
She, Qianhong
Wan, Man Pun
Wang, Rong
Chang, Victor Wei-Chung
Tang, Chuyang Y.
author_sort Yang, Linyan
title Role of calcium ions on the removal of haloacetic acids from swimming pool water by nanofiltration: mechanisms and implications
title_short Role of calcium ions on the removal of haloacetic acids from swimming pool water by nanofiltration: mechanisms and implications
title_full Role of calcium ions on the removal of haloacetic acids from swimming pool water by nanofiltration: mechanisms and implications
title_fullStr Role of calcium ions on the removal of haloacetic acids from swimming pool water by nanofiltration: mechanisms and implications
title_full_unstemmed Role of calcium ions on the removal of haloacetic acids from swimming pool water by nanofiltration: mechanisms and implications
title_sort role of calcium ions on the removal of haloacetic acids from swimming pool water by nanofiltration: mechanisms and implications
publishDate 2018
url https://hdl.handle.net/10356/88017
http://hdl.handle.net/10220/44515
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