Effects of Anions on Perfluorohexanoic Acid Adsorption onto Anion Exchange Polymers, Non-ion Exchange Polymers and Granular Activated Carbon

Abstract

Perfluorohexanoic acid (PFHxA) is increasingly used in industries and widely detected in water environment. Conventional wastewater treatment plants are ineffective to treat PFHxA. Therefore, effective removal techniques are required to minimize health risks and environmental impacts. In this study, adsorption capacities of PFHxA onto three strong base anion exchange polymers (PFA300, PFA400 and A860), two weak base anion exchange polymers (BA103 and MN102), non-ion exchange polymers (XAD4) and granular activated carbon (GAC) were studied by batch experiments. Effects of chloride, sulfate and nitrate ions on the PFHxA adsorption were investigated for all adsorbents. The Freundlich equation was fitted with the equilibrium adsorption data. BA103 exhibited the highest adsorption capacity (412 mg/g) because it had the highest exchange capacity. Amounts of PFHxA adsorbed onto adsorbents decreased when chloride, sulfate and nitrate ions increased in the solution. Nitrate ion had more effects on the adsorption capacities of PFHxA than sulfate and chloride ions. BA103 had the highest adsorption capacity of PFHxA in presence of chloride, sulfate and nitrate ions. BA103 showed as an effective adsorbent to remove PFHxA in water/ wastewater.