Oxidation of polyvinyl alcohol by persulfate activated with heat, Fe2+, and zero-valent iron

The oxidation of polyvinyl alcohol (PVA) by persulfate (S2O82-) activated with heat, Fe2+, and zero-valent iron (Fe(O)) was investigated via batch experiments. It was hypothesized that elevated temperature and the addition of Fe (2+) or Fe(O) into a persulfate-water system could enhance the oxidation of PVA by activated persulfate. Increasing the temperature from 20 to 60 degrees C or 80 degrees C accelerated the oxidation rate of PVA, which achieved complete oxidation in 30 and 10 min, respectively. At 20 degrees C, the addition of Fe2+ or Fe(O) to the persulfate-water system significantly enhanced the oxidation of PVA. The optimal persulfateto-Fe2+ or Fe(O) molar ratio was found to be 1:1. Complete oxidation of PVA was obtained by Fe(O)-activated persulfate in 2 h. Synergistic activation of persulfate by heat and Fe2+ or Fe(O) was also shown to enhance the oxidation of PVA in the persulfate-water system. By using CC-MS analysis, an oxidation product of PVA was identified as vinyl acetic acid (C4H6O2), which is readily biodegradable. Our results suggest that the oxidative treatment of PVA by activated persulfate is a viable option for the pretreatment of PVA-laden wastewater to enhance its biodegradability. (C) 2009 Elsevier B.V. All rights reserved.