Catalytic nanofiber composite membrane by combining electrospinning precursor seeding and flowing synthesis for immobilizing ZIF-8 derived Ag nanoparticles

Abstract

An Ag@PAN catalytic nanofiber composite membrane has been fabricated by combining electrospinning PAN nanofiber seeding with 2-MI and flowing synthesis. ZIF-8 can be immobilized on the surface of the nanofibers with Zn(NO3)2 solution flowing through the 2-MI/PAN nanofiber membrane and Ag nanoparticles can be immobilized on the nanofibers with Zn2+ in ZIF-8 exchanged by Ag+ followed with reduction reaction. The characteristics of XRD, XPS, FTIR, TGA, HRTEM, and BET proved the successful immobilization of Ag nanoparticles derived from ZIF-8 on PAN nanofiber. The permeance of the Ag@PAN catalytic nanofiber composite membrane can reach 19,227 L m−2 h−1 bar−1 with Ag nanoparticles immobilization amount of 49.64%. The p-NP conversion reaction is addressed for the catalytic performance of the Ag@PAN catalytic nanofiber composite membrane. The conversion rate of 99% can be achieved under the condition of p-NP concentration of 0.025 mM and membrane flux of 300 L m−2 h−1. The apparent reaction rate constant of 236.63 min−1 can be achieved by flowing through mode, which is 4-5 orders of magnitude higher than that in a stirred tank reactor with Ag powders as the catalyst. The catalytic performance of the composite membranes has not declined significantly after ten cycles of the catalysis experiment, implied the good repeatability of the Ag@PAN catalytic nanofiber composite membranes.