Organic solvent-free constructing of stable zeolitic imidazolate framework functional layer enhanced by halloysite nanotubes and polyvinyl alcohol on polyvinylidene fluoride hollow fiber membranes for treating dyeing wastewater

Dawei Ji; Haowei Feng; Wanning Wang; Fang Zhou; Shulin Yang; Kaikai Chen; Changfa Xiao

doi:10.1016/j.jcis.2023.01.027

Organic solvent-free constructing of stable zeolitic imidazolate framework functional layer enhanced by halloysite nanotubes and polyvinyl alcohol on polyvinylidene fluoride hollow fiber membranes for treating dyeing wastewater

J Colloid Interface Sci. 2023 Apr 15:636:378-387. doi: 10.1016/j.jcis.2023.01.027. Epub 2023 Jan 9.

Authors

Dawei Ji¹, Haowei Feng², Wanning Wang³, Fang Zhou⁴, Shulin Yang³, Kaikai Chen², Changfa Xiao⁵

Affiliations

¹ Fiber Materials Research Center, Shanghai University of Engineering Science, Shanghai 201620, China; School of Textiles and Fashion, Shanghai University of Engineering Science, Shanghai 201620, China. Electronic address: jdw1106@163.com.
² Fiber Materials Research Center, Shanghai University of Engineering Science, Shanghai 201620, China; School of Textiles and Fashion, Shanghai University of Engineering Science, Shanghai 201620, China.
³ Fiber Materials Research Center, Shanghai University of Engineering Science, Shanghai 201620, China; School of Textiles and Fashion, Shanghai University of Engineering Science, Shanghai 201620, China; School of Material Science and Engineering, and State Key Laboratory of Separation Membranes and Membrane Processes, Tiangong University, Tianjin 300387, China.
⁴ School of Material Science and Engineering, Zhejiang University, Hangzhou 310027, China.
⁵ Fiber Materials Research Center, Shanghai University of Engineering Science, Shanghai 201620, China; School of Textiles and Fashion, Shanghai University of Engineering Science, Shanghai 201620, China; School of Material Science and Engineering, and State Key Laboratory of Separation Membranes and Membrane Processes, Tiangong University, Tianjin 300387, China. Electronic address: xiaochangfa@163.com.

PMID: 36638576
DOI: 10.1016/j.jcis.2023.01.027

Abstract

In this study, zeolitic imidazolate framework (ZIF-8)/polyvinylidene fluoride (PVDF) loose nanofiltration (NF) hollow fiber membranes were fabricated by constructing ZIF-8 functional layer on the PVDF supporting membranes based on the vacuum-assisted assembly process. The ZIF-8 synthesis was completed in a water system, and the synthesized ZIF-8 suspension was directly added to polyvinyl alcohol (PVA) and halloysite nanotubes (HNTs) aqueous solution system without drying to prepare the casting solution, which could solve the agglomeration and poor dispersion problem of ZIF-8 particles. In addition, the embedded HNTs and the loaded PVA among the ZIF-8 layer could improve the bonding strength between the ZIF-8 layer and the supporting membranes. After constructing ZIF-8 functional layer, the pore size of supporting membranes decreased from more than 300 nm to several nanometers. Furthermore, the water contact angle reduced from 91.1° to 54.2°. Applied to treat dye wastewater, the prepared ZIF-8/PVDF membranes maintained high dye rejection (˃99.0 %) for Congo red (CR), but low salt rejection for NaCl (about 2 %). In addition, the flux could reach 21.6 L m^-2h^-1 after continuous filtration 360 min, exhibiting a potential for treating the dye/salt wastewater. In particular, there were no organic solvents used in the work, which provided a promising idea for solvent-free fabrication of loose NF membranes.

Keywords: Dyeing wastewater; Loose NF; PVDF; Solvent-free; ZIF-8.