Adsorption of microsystins and anatoxin-a on nanofiltration membranes

Abstract

This work pretends to study the adsorption of microcystin-LR (MC-LR) and anatoxin-a (ATX-a) on nanofiltration membranes and to understand the adsorption behaviour with the solution chemistry (background natural organic matter (NOM) and in the presence of ATX-a). Results demonstrate that MC-LR adsorption increases with water recovery due to the increase in MC-LR feed concentration. MC-LR adsorption is governed by hydrophobic interactions established between the membrane surface and the MC-LR molecules, and between the MC-LR molecules. For ATX-a, adsorption onto the membrane surface is governed by electrostatic attractions and the background NOM minimises the ATX adsorption. When ATX-a and MC-LR are both present in water, adsorption is higher for ATX-a than for MC-LR and is higher at pH 4 for both cyanotoxins.