Aflatoxin B1 removal by multifunctional membrane based on polydopamine intermediate layer

A green and mild method for aflatoxin B1 (AFB1) removal from food and drinking is highly required due to its high toxicity to human. In this study, membrane technology was attempted firstly to remove AFB1 via two protocols, membrane adsorber and biocatalytic membrane. Four polyvinylidene fluoride microfiltration membranes with different pore size were used to prepare membrane adsorber through successively coating polydopamine (PDA) and polyethyleneimine (PEI) on the membrane surface, and laccase was then loaded on the PDA/PEI-coated membrane to prepare biocatalytic membrane. Although biocatalytic membrane could remove AFB1 by both adsorption and enzymatic degradation, membrane adsorber outperformed thanks to its greater AFB1 removal efficiency (71%) and permeate flux (60 L·m−2·h−1) under gravity-driven flow-through mode. Hydrogen bonding together with electrostatic attraction was its main adsorption mechanism, and thus alkaline cleaning could fully desorb AFB1 from the membrane and further degrade detached AFB1. The contaminative apple juice was treated by such membrane adsorber, which could achieve a constant AFB1 removal for 7 reuse cycles.