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(0)) was investigated via batch experiments. It was hypothesized that elevated temperature and the addition of Fe2+ or Fe(0) into a persulfate-water system could enhance the oxidation of PVA by activated persulfate. Increasing the temperature from 20 to 60 °C or 80 °C accelerated the oxidation rate of PVA, which achieved complete oxidation in 30 and 10 min, respectively. At 20 °C, the addition of Fe2+ or Fe(0) to the persulfate-water system significantly enhanced the oxidation of PVA. The optimal persulfate-to-Fe2+ or Fe(0) molar ratio was found to be 1:1. Complete oxidation of PVA was obtained by Fe(0)-activated persulfate in 2 h. Synergistic activation of persulfate by heat and Fe2+ or Fe(0) was also shown to enhance the oxidation of PVA in the persulfate-water system. By using GC-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.