Comparison of Cationic Surfactants for Activated Carbon Modification for Cr(VI) Removal

摘要

The study investigated the effect of cationic surfactants [e.g., cetyltrimethylammonium chloride (CTAC), myristyltrimethyiammonium bromide (MTAB) and decyltrimethylammonium bromide (DTAB)] loading on activated carbon and application of these modified carbons for Cr(VI) removal from aqueous phase. Adsorption isotherm tests indicate that the surfactant modification method was effective in improving activated carbon's adsoqjtion capacity. At best, CTAC-modified carbon was able to adsorb 64.10 mg Cr(VI)/g at pH 6 as compared to that of 5.53 mg/g for virgin GAC. Langmuir isothenn and pseudo-second-order kinetics models were found to describe well the Cr(VI) adsorption behaviour on activated carbon. Also, adsorption of Cr(VI) decreased slightly with the increase of pH from 2 to 8 while adsorption was highly dependent on pH at pH 8-11. In addition, surfactant’s atmchment to carbon surface was strong and less than 5 % of the surfactant desorbed during Cr(VI) adsorption.