Ultrafiltration behaviors of alginate blocks at various calcium concentrations

Alginate, a linear copolymer, is composed of 1,4-linked β-d-mannuronic acid (M) and α-l-guluronic acid (G), which are combined into homopolymeric blocks (MM-block and GG-block) and heteropolymeric block (MG-block). It has been widely used as a model foulant in various studies of membrane fouling, th...

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Main Authors: Meng, Shujuan, Winters, Harvey, Liu, Yu
Other Authors: School of Civil and Environmental Engineering
Format: Article
Language:English
Published: 2015
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Online Access:https://hdl.handle.net/10356/102971
http://hdl.handle.net/10220/38689
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-1029712020-09-26T21:57:50Z Ultrafiltration behaviors of alginate blocks at various calcium concentrations Meng, Shujuan Winters, Harvey Liu, Yu School of Civil and Environmental Engineering Nanyang Environment and Water Research Institute DRNTU::Engineering::Environmental engineering::Water treatment Alginate, a linear copolymer, is composed of 1,4-linked β-d-mannuronic acid (M) and α-l-guluronic acid (G), which are combined into homopolymeric blocks (MM-block and GG-block) and heteropolymeric block (MG-block). It has been widely used as a model foulant in various studies of membrane fouling, thus this study investigated the impacts of calcium ion on MG-, MM- and GG-blocks of alginate and the filtration behaviors of the three types of alginate blocks at different concentrations of calcium ion. Results showed that calcium ion had the most serious effects on GG-blocks and significantly promotes the formation of transparent exopolymeric particles (TEP) from GG-blocks which in turn led to rapid formation of thick cake layer on membrane surface during the filtration of GG-blocks. As for MM-blocks, it was found that the formation of TEP was proportional to the Ca2+ concentration in MM-blocks solution, while the membrane fouling was enhanced by Ca2+ in the filtration of MM-blocks solution. Unlike MM- and GG-blocks, MG-blocks were nearly not affected by addition of calcium ion, as the result, there was no significant increase in TEP. The initial fouling rates and the mass of foulants deposed on the membrane surfaces further revealed a close correlation between the TEP concentration and the membrane fouling propensity. The observations by field emission scanning electron microscope (FESEM) and atomic force microscope (AFM) further confirmed the formation process of the cake layer by TEP on the membrane surface. This study offers deep insights into the development of membrane fouling by different alginate blocks in the presence of calcium ion, and suggests that TEP formed from alginate blocks played a very significant role in the fouling development. Accepted version 2015-09-15T05:43:37Z 2019-12-06T21:03:02Z 2015-09-15T05:43:37Z 2019-12-06T21:03:02Z 2015 2015 Journal Article Meng, S., Winters, H., & Liu, Y. (2015). Ultrafiltration behaviors of alginate blocks at various calcium concentrations. Water Research, 83, 248-257. 0043-1354 https://hdl.handle.net/10356/102971 http://hdl.handle.net/10220/38689 10.1016/j.watres.2015.06.008 en Water Research © 2015 Elsevier Ltd. This is the author created version of a work that has been peer reviewed and accepted for publication by Water Research, Elsevier. 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.2015.06.008]. 21 p. application/pdf
institution Nanyang Technological University
building NTU Library
country Singapore
collection DR-NTU
language English
topic DRNTU::Engineering::Environmental engineering::Water treatment
spellingShingle DRNTU::Engineering::Environmental engineering::Water treatment
Meng, Shujuan
Winters, Harvey
Liu, Yu
Ultrafiltration behaviors of alginate blocks at various calcium concentrations
description Alginate, a linear copolymer, is composed of 1,4-linked β-d-mannuronic acid (M) and α-l-guluronic acid (G), which are combined into homopolymeric blocks (MM-block and GG-block) and heteropolymeric block (MG-block). It has been widely used as a model foulant in various studies of membrane fouling, thus this study investigated the impacts of calcium ion on MG-, MM- and GG-blocks of alginate and the filtration behaviors of the three types of alginate blocks at different concentrations of calcium ion. Results showed that calcium ion had the most serious effects on GG-blocks and significantly promotes the formation of transparent exopolymeric particles (TEP) from GG-blocks which in turn led to rapid formation of thick cake layer on membrane surface during the filtration of GG-blocks. As for MM-blocks, it was found that the formation of TEP was proportional to the Ca2+ concentration in MM-blocks solution, while the membrane fouling was enhanced by Ca2+ in the filtration of MM-blocks solution. Unlike MM- and GG-blocks, MG-blocks were nearly not affected by addition of calcium ion, as the result, there was no significant increase in TEP. The initial fouling rates and the mass of foulants deposed on the membrane surfaces further revealed a close correlation between the TEP concentration and the membrane fouling propensity. The observations by field emission scanning electron microscope (FESEM) and atomic force microscope (AFM) further confirmed the formation process of the cake layer by TEP on the membrane surface. This study offers deep insights into the development of membrane fouling by different alginate blocks in the presence of calcium ion, and suggests that TEP formed from alginate blocks played a very significant role in the fouling development.
author2 School of Civil and Environmental Engineering
author_facet School of Civil and Environmental Engineering
Meng, Shujuan
Winters, Harvey
Liu, Yu
format Article
author Meng, Shujuan
Winters, Harvey
Liu, Yu
author_sort Meng, Shujuan
title Ultrafiltration behaviors of alginate blocks at various calcium concentrations
title_short Ultrafiltration behaviors of alginate blocks at various calcium concentrations
title_full Ultrafiltration behaviors of alginate blocks at various calcium concentrations
title_fullStr Ultrafiltration behaviors of alginate blocks at various calcium concentrations
title_full_unstemmed Ultrafiltration behaviors of alginate blocks at various calcium concentrations
title_sort ultrafiltration behaviors of alginate blocks at various calcium concentrations
publishDate 2015
url https://hdl.handle.net/10356/102971
http://hdl.handle.net/10220/38689
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