Capacitive deionization and disinfection of seawater effected by nano CuAg@C graphene electrodes

Abstract

The total water storage on earth contains 97% of seawater Seawater is therefore becoming the main water resource for drinking water in the near future Capacitive deionization (CDI) for desalination has advantages of low energy consumption economical attraction and environmental friendly which can be applied in removing the salt from brine industrial water softening and groundwater metal removal During CDI an electric field is applied between two electrodes The opposed ions are forced toward the electrical double layer (EDL) formed on the electrode surfaces Graphene (rGO) having unique thermal electronic and mechanical properties can be used for the CDI electrodes In this work the core-shell nanoparticles dispersed on rGO were prepared and characterized by SEM TEM FTIR Raman BET surface area analysis and cyclic voltammetry The nano core CuAg encapsulated in carbon-shell having the particles size of 10-15 nm were also determined by small angle X-ray scattering (SAXS) spectroscopy CuO and Cu2O in Cu-Ag@C are observed by component-fitted synchrotron X-ray adsorption near edge structure (XANES) spectroscopy The hydrophilic GO was reduced to the hydrophobic rGO with hexamethylene tetramine which is a nontoxic reductant The specific capacitances of rGO and Cu-Ag@C/rGO are 493 and 716 F/g respectively Using the Cu-Ag@C/rGO electrodes for CDI the NaCl removal efficiency is 35 % and the regeneration can be completed in a very short time (5 min) Additionally the disinfection efficiency is as high as 90% in the 4-h contact time It is clear that the Cu-Ag@C/rGO electrodes have a desirable desalination performance with very high disinfection ability in the CDI process

Date of Award	2015 Jun 9
Original language	English
Supervisor	Hong-Paul Wang (Supervisor)