Green preparation of polyvinylidene fluoride loose nanofiltration hollow fiber membranes with multilayer structure for treating textile wastewater

Dawei Ji; Changfa Xiao; Jian Zhao; Kaikai Chen; Fang Zhou; Yifei Gao; Tai Zhang; Haoyang Ling

doi:10.1016/j.scitotenv.2020.141848

Green preparation of polyvinylidene fluoride loose nanofiltration hollow fiber membranes with multilayer structure for treating textile wastewater

Sci Total Environ. 2021 Feb 1:754:141848. doi: 10.1016/j.scitotenv.2020.141848. Epub 2020 Aug 20.

Authors

Dawei Ji¹, Changfa Xiao², Jian Zhao¹, Kaikai Chen³, Fang Zhou⁴, Yifei Gao⁴, Tai Zhang¹, Haoyang Ling⁴

Affiliations

¹ School of Textile Science and Engineering, Tiangong University, Tianjin 300387, China; State Key Laboratory of Separation Membranes and Membrane Processes, Tiangong University, Tianjin 300387, China.
² School of Textile Science and Engineering, Tiangong University, Tianjin 300387, China; State Key Laboratory of Separation Membranes and Membrane Processes, Tiangong University, Tianjin 300387, China. Electronic address: xiaochangfa@163.com.
³ Institute of Textiles and Clothing, Hong Kong Polytechnic University, Hung Hom, Kowloon 999077, Hong Kong, China.
⁴ School of Material Science and Engineering, Tiangong University, Tianjin 300387, China.

PMID: 32898778
DOI: 10.1016/j.scitotenv.2020.141848

Abstract

In this work, polyvinylidene fluoride (PVDF) loose nanofiltration (NF) hollow fiber membranes with multilayer structure were prepared successfully based on a solvent-free process. Graphene oxide (GO) was used to cover the interface pores of the pristine PVDF membranes via vacuum filtration, and polypyrrole (PPy) was polymerized on the surface to further decorate the membrane structure. Interestingly, the modified membranes exhibited a multilayer structure due to synergistic effect of GO and PPy. The structure and property of PVDF loose NF membranes were investigated in detail. After modifying by GO and PPy, the hydrophilicity improved obviously. Moreover, the molecular weight cut off (MWCO) was about 3580 Da, and the smallest pore size of skin layer decreased to 2.5-4 nm. Furthermore, the PVDF loose NF hollow fiber membranes presented a high dye rejection (˃98.5%) for negative dyes, whereas a low salt rejection for NaCl (about 4%), showing a great potential for separating dye/salt accurately. Specifically, there were not any solvent used in all the preparation processes. The work offered a novel strategy for green preparation of loose NF membranes.

Keywords: Green; Hollow fiber membranes; Loose NF; Multilayer structure; Textile wastewater.