Neurotoxic and hepatotoxic cyanotoxins removal by nanofiltration

This study investigates the influence of chemical feed characteristics on nanofiltration performance for cyanotoxins removal, namely the neurotoxic anatoxin-a (alkaloid of 166 g/mol, positively charged) and the hepatotoxic microcystins (cyclic peptides of 1000 g/mol, negatively charged). Results indicate that NF membranes are an effective barrier against anatoxin-a and microcystins in drinking water. Anatoxin-a and especially microcystins were almost completely removed, regardless of the variations in feed water quality (natural organic matter and competitive toxin), the water recovery rate and the pH values. Anatoxin-a removal was governed by electrostatic interactions and steric hindrance, whereas for microcystins the latter was the main mechanism. In turn, fluxes were significantly impacted by background organics and, especially, inorganics (pH, calcium).