Cellulose Derived Graphenic Fibers for Capacitive Desalination of Brackish Water

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• 作者：Nalenthiran Pugazhenthiran ; Soujit Sen Gupta ; Anupama Prabhath ; Muthu Manikandan ; Jakka Ravindran Swathy ; V. Kalyan Raman ; Thalappil Pradeep
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：September 16, 2015
• 年：2015
• 卷：7
• 期：36
• 页码：20156-20163
• 全文大小：456K
• ISSN：1944-8252

文摘

We describe a simple and inexpensive cellulose-derived and layer-by-layer stacked carbon fiber network electrode for capacitive deionization (CDI) of brackish water. The microstructure and chemical composition were characterized using spectroscopic and microscopic techniques; electrochemical/electrical performance was evaluated by cyclic voltammetry and 4-probe electrical conductivity and surface area by Brunauer鈥揈mmett鈥揟eller analysis, respectively. The desalination performance was investigated using a laboratory batch model CDI unit, under fixed applied voltage and varying salt concentrations. Electro-adsorption of NaCl on the graphite reinforced-cellulose (GrC) electrode reached equilibrium quickly (within 90 min) and the adsorbed salts were released swiftly (in 40 min) back into the solution, during reversal of applied potential. X-ray photoelectron spectroscopic studies clearly illustrate that sodium and chloride ions were physisorbed on the negative and positive electrodes, respectively during electro-adsorption. This GrC electrode showed an electro-adsorption capacity of 13.1 mg/g of the electrode at a cell potential of 1.2 V, with excellent recyclability and complete regeneration. The electrode has a high tendency for removal of specific anions, such as fluoride, nitrate, chloride, and sulfate from water in the following order: Cl^{鈥?/sup> > NO₃鈥?/sup> > F鈥?/sup> > SO₄2鈥?/sup>. GrC electrodes also showed resistance to biofouling with negligible biofilm formation even after 5 days of incubation in Pseudomonas putida bacterial culture. Our unique cost-effective methodology of layer-by-layer stacking of carbon nanofibers and concurrent reinforcement using graphite provides uniform conductivity throughout the electrode with fast electro-adsorption, rapid desorption, and extended reuse, making the electrode affordable for capacitive desalination of brackish water.}