title: Promoted degradation of perfluorooctanic acid by persulfate when adding activated carbon.
abstract: Treatment of persistent perfluorooctanoic acid (PFOA) in water using persulfate (PS) oxidation typically requires an elevated temperature or UV irradiation, which is energy-consuming. Under relatively low temperatures of 25-45°C, activated carbon (AC) activated PS oxidation of PFOA was evaluated for its potential of practical applications. With presence of AC in PS oxidation, PFOA removal efficiency at 25°C reached 682% with a high defluorination efficiency of 549% after 12h and few intermediates of short-chain perfluorinated carboxylic acids (PFCAs) were found. The removal and defluorination rates with the combined AC/PS system were approximately 12 and 19 times higher than those of the PS-only system, respectively. Activated carbon not only removes PFOA through adsorption, but also activates PS to form sulfate radicals that accelerate the decomposition and mineralization of PFOA. The activation energy for PS oxidation of PFOA was reduced from 668 to 261kJ/mol by the catalytic effect of AC, which implies a lower reaction temperature and a shorter reaction time would suffice. A 2-cycle schematic reaction mechanism was used to describe PS oxidation of PFOA with the generation of various intermediates and end-products.
authors: Research Center for Environmental Pollution Prevention and Control Technology, Graduate Institute of Environmental Engineering, National Taiwan University, 71, Chou-Shan Rd., Taipei 106, Taiwan, ROC.
authors: Yu-Chi
authors: YC
authors: Lee
authors: Shang-Lien
authors: SL
authors: Lo
authors: Jeff
authors: J
authors: Kuo
authors: Chin-Pao
authors: CP
authors: Huang
mesh_terms: D002210:Caprylates / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry; D005466:Fluorocarbons / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D013431:Sulfates / Q000737:chemistry*; D013696:Temperature; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
chemical_list: D002210:Caprylates; D005466:Fluorocarbons; D013431:Sulfates; D014874:Water Pollutants, Chemical; D002244:Carbon; C023036:perfluorooctanoic acid
keywords: Activated carbon; Perfluorooctanoic acid; Persulfate; Temperature; pH