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Capacitive deionization (CDI) is an emerging electrochemical desalination technique for the energy- efficient removal of dissolved ions from aqueous solution. This is a first research attempt which describes the influence of dye molecules on capacitive deionization of salt solution. In this regard, a CDI flow cell has been fabricated and tested in order to scrutinize the electrosorptive removal of three different dye molecules such as amido black 10B (AB) (acidic dye), eosin yellow (EY) (neutral dye) and methyl violet (MV) (basic dye) from synthetic aqueous solutions. The electrosorption capacitance was analyzed by cyclic voltammetry cell and CDI flow cell using activated carbon cloth (ACC) electrodes with 1 cm 2 and 24 cm 2 surface areas respectively. The capacitance values of 106 and 99 F/g correspondingly were obtained for a steady-state CV and CDI flow cell with 50 mM Na 2 SO 4 electrolyte solution. In addition to this, the dye removal efficiency was also examined by a CDI flow cell for the solution containing 10 ppm of dye and 500 ppm of Na 2 SO 4 . The experimental results substantiate that EY exhibits strong adsorption during charging and strong desorption during discharge cycle when compared with other two dye molecules (AB & MV). Conclusively, electrosorption of dye molecules at the carbon cloth electrodes surface was found in the following order: EY > AB > MV. [ABSTRACT FROM AUTHOR]

Graphene is a promising electrode material for high performance supercapacitors and capacitive deionization applications. Our present work is focused on the synthesis of graphene nanosheets by the reduction of graphite oxide using focused solar irradiation. The as prepared graphene nanosheets are characterized by Transmission Electron Microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, X-ray Photoelectron Spectroscopy (XPS) and Fourier transform infrared spectroscopic (FTIR) techniques for surface, structural and functional group analysis. Electrochemical properties are studied using cyclic voltammetry and galvanostatic charge-discharge method. The fabricated supercapacitor cell shows high specific capacitance of 265.9 and 187.1 F g −1 with 6 M KOH and ionic liquid electrolyte (EMIMBF 4 ), respectively. High energy density of 58.5 Wh Kg −1 has been obtained for EMIMBF 4 electrolyte. The electrosorption studies were also performed to study the effect of deionization behaviour of the prepared graphene under flow in between electrodes technique. The electrosortion capacity of 22.4 mg/g has been obtained for 100 mM NaCl (∼5844 mg/l) solution at the applied voltage of 1 V. [ABSTRACT FROM AUTHOR]

Here a facile strategy was proposed to prepare graphene (GE) sheets with unique mesoporous morphology (denoted as mGE) via a simple carbothermal reaction by using KMnO 4 as the etching agent. The morphology, structure and electrochemical properties of mGE were investigated by scanning electron microscopy, transmission electron microscopy, Raman spectra, nitrogen adsorption-desorption, cyclic voltammetry and electrochemical impedance spectroscopy. The electrosorption performance of mGE in NaCl solution was studied and compared with GE. The results show that mGE electrode exhibits a high electrosorption capacity of 6.38 mg g −1 when the initial NaCl concentration is ∼75 mg L −1 and applied voltage is 1.2 V, which is about 2.3 and 1.5 times of those of GE (2.76 mg g −1 ) and recently reported microporous GE (∼4 mg g −1 ), respectively, and also higher than those of other carbon materials in the literatures, due to short ion diffusion path, large accessible surface area and low charge transfer resistance offered by its novel mesoporous structure. Therefore, it is believed that mGE is a promising candidate for practical capacitive deionization applications. [ABSTRACT FROM AUTHOR]