Improved conductivity and anti(bio)fouling of cation exchange membranes by AgNPs-GO nanocomposites

Abstract

"Nafion and Ultrex membranes were modified with nanocomposites (NCs) of silver nanoparticles (AgNPs) immobilized on graphene oxide (GO) as a thin film, using a polydopamine adhesive (pda). The morphological, physicochemical, transport, electrochemical and anti-(bio)fouling properties were determined. The results indicated that the silver nanoparticles were immobilized on adsorption points of the graphene oxide to form nanocomposites. Polydopamine acted satisfactorily as a support and adhesive to bind the nanocomposites to the outer and inner surface of the membranes. The hydrophilicity, ionic exchange capacity, fixed ion concentration, electrochemical and conductivity properties were mostly enhanced in the modified Nafion membranes with pdaGO and pdaNC, but in the Ultrex a shortening of the hydrophilic channels occurred. The impedance results suggested that both modified membranes were more conductive at low frequencies or longer times, due to an adequate interfacial distribution of charges. The differences were attributed to the microstructure of the membranes. Also, the modification of Nafion and Ultrex membranes improved their anti-(bio)fouling properties. Hence, both membranes could be used in separation systems, since they allow a higher charge transfer and low energy consumption."