Chlorine-resistant sulfochlorinated and sulfonated polysulfone for reverse osmosis membranes by coating method

Yali Zhao; Lei Dai; Qifeng Zhang; Shengyang Zhou; Suobo Zhang

doi:10.1016/j.jcis.2019.01.104

Chlorine-resistant sulfochlorinated and sulfonated polysulfone for reverse osmosis membranes by coating method

J Colloid Interface Sci. 2019 Apr 1:541:434-443. doi: 10.1016/j.jcis.2019.01.104. Epub 2019 Jan 25.

Authors

Yali Zhao¹, Lei Dai², Qifeng Zhang³, Shengyang Zhou¹, Suobo Zhang⁴

Affiliations

¹ Key Laboratory of Ecomaterials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China; University of Science and Technology of China, Hefei 230026, China.
² Key Laboratory of Ecomaterials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China.
³ Key Laboratory of Ecomaterials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China. Electronic address: qfzhang@ciac.ac.cn.
⁴ Key Laboratory of Ecomaterials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China; University of Science and Technology of China, Hefei 230026, China; Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), China. Electronic address: sbzhang@ciac.ac.cn.

PMID: 30711637
DOI: 10.1016/j.jcis.2019.01.104

Abstract

In this work, sulfochlorinated polysulfone (SC-PSf), a functional polysulfone with chlorine resistance, was synthesized through metalation sulfochlorination of polysulfone (PSf). For endowing the required hydrophilicity of SC-PSf, the sulfonyl chloride groups on SC-PSf were partially hydrolyzed to sulfonic groups to produce sulfonated SC-PSf (SC-S-PSf). Thin film composite (TFC) membranes for reverse osmosis application were fabricated by coating solution of SC-S-PSf on porous PSf substrate and then crosslinked by piperazine (PIP) to form polysulfone-sulfamide (PSSA) skin layer. In order to enhance the spreadability of polymer solution on PSf supporting layer, tetrabutylammonium chloride (TBAC), a common surfactant, was added into the coating solution. A flawless membrane was acquired only by a single coating step and at dilute SC-S-PSf solution when TBAC was added into polymer solution. Through optimizing coating conditions, the NaCl rejection and water flux of PSSA membrane reached 96.9% and 17.8 L/m²h under brackish desalination conditions. Moreover, the PSSA membrane exhibited the long-term stability against chlorine during the operation condition of 2000 ppm NaOCl for 10 days. The salt rejection of PSSA only decreased by 1%. In contrast, the salt rejection of polyamide membrane decreased by 8% under the same condition.

Keywords: Chlorine resistance; Polysulfone-sulfamide; RO membrane; Sulfochlorinated polysulfone.