| Summary: | 碩士 === 國立成功大學 === 環境工程學系 === 103 === 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.
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