An innovative technology for wastewater treatment using adsorption and electrochemical regeneration has been developed at the University of Manchester. The process uses a low capacity graphitic adsorbent material (a graphite intercalation compound, NyexTM 1) which can be regenerated electrochemically. In this study, we investigate the characteristics of a new, partially porous adsorbent material, NyexTM 2 which offers increased surface area in comparison with NyexTM NyexTM 2 was found to have an adsorption capacity of almost three times that of NyexTM The electrical conductivity of a NyexTM 2 was found to be double that of NyexTM 1, enabling improvements in the electrochemical regeneration characteristics. The removal of an anionic azo dye, acid violet 17, from aqueous solution using NyexTM 1 and 2 was investigated under various operating conditions. The adsorption of acid violet 17 on NyexTM 2 was found to be comparatively fast with 75 % of the equilibrium capacity being achieved within 5 min. The parameters affecting the regeneration efficiency including the charge passed, current density, treatment time, adsorbent bed thickness, and pH were investigated. An electrochemical regeneration efficiency of around 1 % was achieved for a fully loaded NyexTM 2 in a sequential batch electrochemical cell with a regeneration time of 6 min and a charge passed of 1 C g−1 at a current density of 14 mA cm−2. The charge required for electrochemical regeneration was found to be approximately equal to theoretical charge required for complete oxidation of the adsorbed acid violet 17, making process design relatively simple. NyexTM 2 was found to be an economic adsorbent with relatively small electrical energy consumption required (31 J mg−1 of acid violet 17 treated, compared to 52 J mg−1 of acid violet 17 for NyexTM 1). Multiple adsorption/regeneration cycles presented no loss in adsorptive capacity and material loses over five adsorption/regeneration cycles.
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