Abstract
Perfluorochemicals (PFCs) are widely consumed as surfactants, additives, repellent, insecticides, and so on. Recently some of them have been suspected as persistent, bioaccumulated and toxic chemicals. Reports on PFCs in surface and drinking water indicated ineffective removal in current water treatment facilities including granular activated carbon (GAC) filtration. This study aims to understand characteristics of GAC adsorption to remove PFCs. Freundlich equation and the homogenous surface diffusion model (HSDM) were successfully applied to interpret experimental data. GAC showed increasing adsorption capacities and velocities for PFCs with longer carbon chain length. Carbon fouling effect reduced GAC adsorption capacities of PFCs more intensively than those of background organics. Coexisting organics and bulk pH did not significantly affect adsorption kinetics of PFCs. Coal-based GAC performed better to remove PFCs than nutshell-based GAC. Preliminary experiments by the raid small scale column test (RSSCT) showed effective removal of some PFCs, including highly concerned perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA).
