Products Cited in Publications Worldwide Polyamide-Crystalline Covalent Organic Framework Dual-Layer Nanofiltration Membrane with Improved Ion Selectivity

Polyamide-Crystalline Covalent Organic Framework Dual-Layer Nanofiltration Membrane with Improved Ion Selectivity

Khandge, Rahul Sampat; Nguyen, Thanh-Tin; Qiang, Zhiqin; Yu, Ho-Kuan; Ma, Xiaoli

DOI:

Abstract

There is growing interest in designing nanofiltration (NF)membranes for selective separations. However, controlling the formationprocess of polyamide (PA) membranes to achieve simultaneous improve-ments in permeance and selectivity remains challenging. The use of aninterlayer has recently emerged as a promising strategy to tackle this trade-off. Herein, nanoporous covalent organic framework (COF) interlayers wereemployed to facilitate the formation of a thin PA selective membrane layer.The COF interlayers were synthesized through a counter-diffusion IPmethod, during which the solvent and catalyst were tailored to achievedifferent extents of COF crystallinity. PA membranes made by conventionalIP on these COF interlayers were found to show better performance thanthat made on a pristine polymer support. In addition, crystalline COFsresulted in a PA layer featuring a narrow pore size distribution and a highnegative surface charge. The resulting dual-layer membrane exhibited enhanced NF performance, with superior rejection for divalentsalts (Na2SO4, 99.6%; MgSO4, 97.4%), enhanced selectivity for mono/divalent salts (NaCl/Na2SO4, 137), and high waterpermeance. The combined permeance and selectivity exceed those of most reported NF membranes, making the PA/crystallineCOF dual-layer membrane promising for NF-based selective separation.

Keywords

polyamide ; covalent organic framework ; interlayer ; nanofiltration ; selectivity

Purchased from AmBeed

A22772634374-88-495%

2,4,6-Trihydroxybenzene-1,3,5-tricarbaldehyde

12.0/250mg

Detail