Determination of pore characteristics and molecular weight cut-off (MWCO) of uf membranes via solute transport and mathematical method

Abstract

 The objective of this study was to explore a non-analytical but empirical and mathematical method for the determination of pore size and pore density of several polymeric tailor-made membranes. The pro­posed method used the fractional rejection concept of solute in membrane pores. Experiment was conduct­ed with Polyethylene glycol PEG and PEO with different molecular weights as feed water, each feed solution had concentration of 100 mg/L, and applied ultrafiltration test with the LSMM PES based membranes. The data was interpreted using log-normal probability function model to describe the membrane sieving curves and the Hagen-Poiseuille equation for surface porosity/density. It was revealed that the solute transport method could provide relatively values of pore size and pore density for reference. It also proved the impacts of LSMM additives on membrane properties in which at low LSMM incorporation, the thinner membranes (0.2 mm thick) had higher mean pore size, accordingly higher the MWCO while at higher additive concen­tration, the opposite was observed.

Keywords: Pore characterization, solute transport method, surface additives, ultrafiltration membrane, MWCO.

Received: September 6th, 2017; revised: October 20th, 2017; accepted: November 2nd, 2017