Dongsheng Zhao,Jiyu Song, Yiwen Zhang, Zhiquan Lin, Bo He,*, NanfuQiao,  Kangping Huang,Wei Zhang , Shuang Ge, Yuying Li , B. Larry Li,KangXie , Guicai Liu ,*

Coupling activation and curing to tune the permselectivity of poly  (piperazine amide) nanofiltration membranes. Journal of Water Process Engineering 53 (2023) 103783

Abstract: To tune both water transport and solute rejection (i.e., permselectivity) of nanofiltration (NF) membranes,  polyamide (PA) films were synthesized under the same interfacial polymerization (IP) conditions following  distinct posttreatments, and the underlying relationship between the PA structure and membrane performance  was systematically investigated. The combination of hexane activation and water curing was the optimal post treatment process, which significantly increased membrane permeability from 6.7 ± 0.4 to 19.8 ± 0.8  L⋅m− 2 ⋅h− 1 ⋅bar− 1 and enhanced the selectivity of NaCl/Na2SO4 from 9.6 ± 1.2 to 45.8 ± 0.8. For this combined  posttreatment process, the outstanding permeability was due to the enlarged PA film pore size, the enhanced  hydrophilicity and the reduced PA thickness and crosslinking degree, and the high NaCl/Na2SO4 selectivity was attributed to the increased electrostatic repulsion between the hydrolyzed acyl chloride groups (i.e., carboxyl  groups) and divalent anions. Furthermore, a continuous filtration of 10 days was implemented, and the permeation flux and salt rejection trends for the fabricated PA membranes were maintained at high levels, which  indicated excellent long-term stability for the combined posttreatment process. The results of the current study  are of paramount practical significance for the reconciliation of permeability and selectivity in water treatment  and resource recovery from wastewater.

Keywords:  Nanofiltration  ;Permselectivity  ;Combined posttreatment  ;Reduced PA crosslinking  ;Hydrolyzed acyl chloride groups  

网站链接： https://doi.org/10.1016/j.jwpe.2023.103783