Effect of KMnO4 treatment of granular activated carbon on the removal of natural organic matter

In drinking water the amount of natural organic matter (NOM), measured as dissolved organic carbon (DOC), should be maintained at a low enough concentration to increase the stability of chlorine and minimise the disinfection by-products. This work focuses on the methods to enhance the performance of granular activated carbon (GAC) by modifying the surface of GAC by pre-treatment with potassium permanganate (KMnO4) at two loading (0.1 and 1% w/w KMnO4/GAC). The batch DOC adsorption experimental results at two solid to liquid ratios (5 g GAC/L; 0.5 g GAC/L) indicated that KMnO4 treatment did neither improve NOM removal nor change the NOM composition in the treated water. There was also no evidence in change of GAC pore structure due to KMnO4 pre-treatment. Therefore, there is no significant benefit of treating GAC with KMnO4 for physical removal of NOM under the tested conditions.