الفهرس | Only 14 pages are availabe for public view |
Abstract Desalination is one of the most promising approaches to supply new fresh water in the context of a rapidly growing global water demand. However, the existing commercial techniques for desalination suffer from important drawbacks, most importantly large energy footprints and high capital costs. This explains why desalination today only accounts for a fraction of a percent of the world‟s potable water supply despite the fact that oceans and seas contain about 97% of the world‟s water. Capacitive deionization (CDI) is being progressed as an auspicious ion removal technique from brackish and seawater. The purpose of the present study is to develop a capacitive deionization (CDI) system using high-surface area carbon and metal oxide nanotube electrodes to achieve energy efficient water desalination. A bench-scale CDI cell was designed and successfully assembled and tested. A novel one-step facile chemical approach to fabricate tubular architectured composite electrodes made of both Titania and Multiwalled carbon nanotubes (TNTs/MWCNTs) has been utilized. The composites have been exploited, for the first time, as electrode materials for capacitive deionization. The composite electrodes were fully characterized via Field Emission Scanning Electron Microscopy (FESEM), Raman spectroscopy, X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS) techniques, and Nitrogen Sorption. The electrochemical response was investigated using Cyclic Voltammetry (CV), Galvanostatic charge/Discharge (GCD), and Potentio Electrochemical Impedance Spectroscopy (PEIS) measurements. The fabricated composite electrodes containing 5 wt% TiO2 nanotubes showed remarkable specific capacitance, conductivity, reversibility, and durability compared to pristine MWCNTs and other MWCNT-based composite electrodes reported in the literature. The desalination IX capability of the composite electrode was investigated using batch mode operation. The electrosorption capacity of the composite electrode containing 5 wt% TiO2 nanotubes (13.2 mg g-1 ) is approximately two fold larger than that of pristine MWCNTs (7.7 mg g-1 ), indicating an improved desalination efficiency. Therefore, the fabricated TNTs/MWCNTs composite electrode is a promising candidate for CDI technology. |