Hairy quaternary ammonium-functionalized metal organic framework integrated in polyacrylonitrile nanofiber membrane for efficient removal of arsenate

Abstract

In this work, the metal–organic framework (MOF) particles (i.e., UiO-66-NH2) was covalently modified with poly(4-vinylpyridine) (P4VP) through surface-initiated atom transfer radical polymerization (SI-ATRP) method. The hair MOF product, referred to as UiO-66-g-P4VP, was then subjected to quaternization with 1-bromoethane, resulting in UiO-66-g-qP4VP (quaternized P4VP is denoted as qP4VP). Finally, these UiO-66-g-qP4VP particles were incorporated into a polymer matrix made of polyacrylonitrile (PAN) to develop a nanofibrous composite membrane using the electrospinning technique. After modification of quaternized P4VP, the surface of the MOFs carry strong positive charges. Therefore, the electrospun UiO-66-g-qP4VP/PAN nanofiber membrane can serve as an adsorbent in efficient removal of negatively charged arsenate through strong electrostatic interactions. The adsorptive efficacy of the nanofiber membrane exhibited considerable stability within the pH spectrum extending from 4 to 10, indicating that the membrane could potentially maintain its functionality across a broad range of pH conditions. Our developed approach opens up an avenue for manufacturing of polyelectrolyte-functionalized MOF nanofiber membranes, which hold great promise for application in water remediation.