Performance of surface modified polyethersulfone membranes for ultrafiltration of aquatic humic substances

Abstract

Many studies have been devoted to mem-brane fouling caused by humic substances (e.g. [1]). However, there are still many consid-erable disagreements about the characteristics and mechanisms of fouling during filtration. Moreover, control of that fouling is still the big challenge. Therefore, it would be desirable having available high-performance membranes with a pronounced and stable resistance towards fouling with humic substances. Surface modifi-cation has been proposed as a most versatile method to reduce the fouling. Membrane modi-fication using negatively charge monomer to reduce the fouling tendency during NOM removal was reported [2]. However, charge based interaction is strongly dependent on the pH and the ionic content of the solution. There-fore, hydrophilization of polymeric membranes with a neutral polymer to produce low-fouling membrane has been considered as a promising approach. This paper presents investigations of the fouling behavior of humic substances obtained by studies of membrane-solute and membrane–solute–solute interactions. Further, a surface modification of polyethersulfone (PES) ultrafiltration (UF) membranes via photograft copolymerization [3] has been evaluated. The target of this modification is to obtain a thin-layer polymer hydrogel composite PES-based UF membrane with the permeability and select-ivity similar to the commercial 10 kDa PES membrane, but having a lower fouling tendency.