Adsorption of Perfluorinated Compounds onto Activated Carbon and Activated Sludge

Abstract

The adsorption of perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) onto powdered activated carbon (PAC) was investigated in the presence and absence of effluent organic matter (EfOM) at an environmentally relevant concentration range (0.1–500 μg/L). Adsorption of PFOS and PFOA to PAC fitted the Freundlich model well (r2>0.98), and adsorption capacity of PFOS (KF=17.48) and PFOA (KF=10.03) in the absence of EfOM was more than one order of magnitude higher than that in the presence of EfOM (KF=0.66 for PFOS, KF=0.20 for PFOA), indicating that EfOM greatly reduces the adsorption capacity of PAC. Moreover, EfOM was characterized by ultrafiltration, and fractions of nominal molecular weights were obtained to investigate their effect on the PFOS and PFOA adsorption. The fraction of 30 kDa, indicating that the similar molecular size of target compounds was the major contributor to adsorption competition. Additionally, biosorption of P...