Adsorption and Efficient Decomposition of Perfluoro Compounds at Plasma–Water Interface

Perfluorooctane sulfonic acid (PFOS) is an environmentally harmful and persistent substance, and thus, effluent controls have been applied. The decomposition of PFOS in water using plasma attached to the water surface has been successfully performed, and the resulting energy efficiency is relatively high compared to that of other methods such as sonochemical processes. The estimation of the amount of PFOS adsorbing to the plasma-water interface showed much higher mole fraction of PFOS (6.0 ×10^-4) than that in bulk water (1.8 ×10^-6) at a PFOS bulk concentration of 50 mg/L. Thus, the plasma can effectively react with PFOS at the water surface and exhibits high energy efficiency.