New insights into the organic fouling mechanism of an in situ Ca2+ modified thin film composite forward osmosis membrane

Xiujuan Hao; Shanshan Gao; Jiayu Tian; Songxue Wang; Huizhong Zhang; Yan Sun; Wenxin Shi; Fuyi Cui

doi:10.1039/C9RA06272F

New insights into the organic fouling mechanism of an in situ Ca²⁺ modified thin film composite forward osmosis membrane†

Xiujuan Hao,^a Shanshan Gao,^b Jiayu Tian,

*^ab Songxue Wang,^a Huizhong Zhang,^a Yan Sun,^c Wenxin Shi^d and Fuyi Cui^d

Author affiliations

* Corresponding authors

^a State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
E-mail: tjy800112@163.com

^b School of Civil Engineering and Transportation, Hebei University of Technology, Tianjin 300401, China

^c School of Civil Engineering, Chang'an University, Xi'an, China

^d College of Urban Construction and Environmental Engineering, Chongqing University, Chongqing 400044, China

Abstract

In this study, the effect of organic substances on the fouling behavior of a thin film composite (TFC) membrane with in situ Ca²⁺ addition (TFC-Ca membrane) was evaluated. Bovine serum albumin (BSA), humic acid (HA) and sodium alginate (SA) were used as surrogate foulants for protein, natural organic substances and polysaccharides, respectively, thus enabling the analysis of foulant–membrane interaction in the membrane fouling process. Fouling experiments were carried out and the fouling mechanism was investigated by extended Derjaguin–Landau–Verwey–Overbeek (XDLVO) theory. SEM-EDX, ICP-OES and TOC analysis were applied to characterize the fouled TFC-Ca membrane. Results suggested that the interfacial free energies obtained from advanced contact angle measurements were correlated strongly with the rates of membrane fouling. In situ Ca²⁺ addition in the TFC membrane resulted in the decrease of the interfacial adhesion free energy (i.e., foulant–membrane interaction) and thus the mitigation of membrane fouling. The permeate flux of TFC-Ca FO membrane after organic fouling could be fully restored by simple physical cleaning. The antifouling mechanism of Ca²⁺ pre-binding carboxyl groups in the TFC-Ca FO membrane was demonstrated, which provides new insights into the development of antifouling TFC membranes in the future.

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Article information

DOI: https://doi.org/10.1039/C9RA06272F
Article type: Paper
Submitted: 12 Aug 2019
Accepted: 18 Nov 2019
First published: 22 Nov 2019
This article is Open Access

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RSC Adv., 2019,9, 38227-38234

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New insights into the organic fouling mechanism of an in situ Ca²⁺ modified thin film composite forward osmosis membrane

X. Hao, S. Gao, J. Tian, S. Wang, H. Zhang, Y. Sun, W. Shi and F. Cui, RSC Adv., 2019, 9, 38227 DOI: 10.1039/C9RA06272F

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