Abstract: Granular activated carbon was modified with KMnO₄ at refluxing. The influence of KMnO₄ concentration on the Cu²⁺ adsorption rate-pH curves and pH was investigated and the effect of the modification with KMnO₄ on the Cu²⁺ adsorption and desorption capacities of activated carbon was studied. The results show that the Cu²⁺ adsorption rate-pH curves and pH of activated carbon move to the lower pH side after modification with KMnO₄. The best result is achieved at 0.03mol/L KMnO₄ concentration. The modification with KMnO₄ has improved the adsorption rate of Cu²⁺ and reduced the consumption of adsorbent by three times compared with that of unmodified carbon. The Cu²⁺ adsorption on the modified and unmodified activated carbon conforms to the Freundlich isothermal adsorption equation. At a same equilibrium concentration of Cu²⁺, the Cu²⁺ adsorption amount on the activated carbon modified with KMnO₄ is about 2.7 times higher than that on unmodified carbon. When 0.35mol/L HCl solution is used as elution solution, the desorption rates of Cu²⁺ on the KMnO₄ modified activated carbon and unmodified activated carbon are 91.1% and 8.8% respectively. The modification with KMnO₄ has not only increased the adsorption capacity of granular activated carbon for heavy metal ions, but also improved its desorption-regeneration performance.

Key words: Activated carbon, Modification, KMnO₄, Adsorption, Cu²⁺