Preparation of graphene oxide nano-composite ion-exchange membranes for desalination application

Abstract

Nano-composite ion-exchange membranes (IEMs) consisting of graphene oxide (GO) (0.5, 1, 2, 5 and 10%) (w/w) and sulfonated polyethersulfone (SPES) of thickness 180 μm are prepared with enhanced electrochemical properties. In particular, the transport properties of SPES are favourably manipulated by the incorporation of GO. Intermolecular interactions between the components in composite membranes are established by FTIR. Membranes are characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) which showed the uniform distribution of GO sheets in SPES matrix. The maximum ionic conductivity has been found in 10% GO composite with higher methanol crossover resistance and selectivity. Water desalination performance of the nano-composite membranes have been evaluated by ionic flux, power consumption and current efficiency during salt removal. 10% GO nano-composite membrane shows 3.51 mol m⁻² h⁻¹ ionic flux, 4.3 kW h kg⁻¹ power consumption and 97.4% current efficiency for salt removal. The values of ionic flux and current efficiency are 19% and 12% higher respectively while 20% lower power consumption is observed as compared to SPES membrane. The strong interfacial interactions due to the insertion of GO nanofillers into the SPES matrix improve the thermal and mechanical properties of the nanocomposite membranes. Nano-composite membrane shows the better performance and higher stability which may be used for the practical application such as DMFC and electrodialysis.