Development of polysulfone membranes and their application for removing rare earth ions from aqueous solutions by polyvinyl alcohol-enhanced ultrafiltration

Abstract

A polymeric ultrafiltration membrane was synthesized from a homogeneous solution of polysulfone (16 and 18% by weights) using N-methyl-2-pyrrolidone as the solvent by employing a phase inversion technique. The prepared membranes were characterized by scanning electron microscopy, water contact angle, and Fourier-transform infrared spectroscopy. The membranes were tested for ultrafiltration properties such as yttrium and lanthanum retention, bovine serum albumin rejection, and ultrapure water permeation measurement. To increase the hydrophilicity of the polysulfone membranes, this study investigates how the amount of polysulfone affects the functions and structure of the membranes produced. Moreover, the addition of polyvinyl pyrrolidone improves the pore size of the membrane to become larger, which can increase its permeability and flux. Based on the results of retention and flux permeation results, a polysulfone membrane (16% by weights) showed the best performance. These membranes were subjected to ultrafiltration tests and the results showed an increased retention of yttrium ions and bovine serum albumin of 99.11% and 18%, respectively. The aim of this study is to evaluate the removal efficiency of yttrium and lanthanum ions (98%) at pH 6 under 4 bar transmembrane pressure using the polyelectrolyte-enhanced ultrafiltration process by incorporating polyvinyl alcohol as a polyelectrolyte chelating agent.

Graphical Abstract