Title: Charge- and Size-Selective Ion Sieving through Graphene based Membranes
Speaker: Dr. Seunghyun Hong
Abstract Details: Ionic selectivity is a major attribute to consider when designing novel membranes for separation technologies. As one of promising candidates for next generation nanofiltration, graphene oxides (GO) membranes with tunable physiochemical properties offers an excellent framework to make highly efficient ion-selective channels without compromising ultrahigh water permeance. Here, I demonstrate ultrahigh charge and size selective ion transport in GO-based membranes with microscopic drift-diffusion method. I identified primary mechanisms governing ionic rejection in GO membranes from precise investigation for a range of ionic species: surface charge groups inside the GO nanochannels are responsible for electrostatically repulsing co-ions. Furthermore, I describe the chemical confinement of interlayer channel in GO membranes, enabling to achieve accurate size selective sieving while water flow is weakly affected. These ionic selectivity opens up new venue for electrodialysis and desalination to GO.