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Adsorption of perchlorate by surfactant-modified activated carbon and its regeneration |
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Abstract Cationic surfactant cetyltrimethylammonium chloride was employed to modify an activated carbon (AC) in an attempt to enhance AC’s adsorption for perchlorate. Breakthrough curves were compared before and after modification. Non-modified AC had very little capacity for perchlorate. CTAC modification greatly improved AC’s adsorption. In addition, adsorption capacity was resilient again changes in influent pH. However, interfering anions, such as NO3-, SO42-, SiO42- and PO43-, showed competition for adsorption, which resulted in decrease in perchlorate removal. Activated carbon was regenerated when it reached breakthrough. A regeneration efficiency of 95% was observed when AC was chemically regenerated by 1 mol/L of HCl solution. And activated carbon was able to be reused directly after regeneration. Thermal regeneration by steam was effective in restoring AC’s pore structure. Perchlorate decomposed at high temperature and was removed thoroughly. However, thermal regeneration caused CTAC to degrade thus regenerated AC had to be re-modified before further application.
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Received: 30 June 2011
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