Photochemical Degradation of Aqueous Polyvinyl Alcohol in a Continuous UV/H2O2 Process: Experimental and Statistical Analysis

Polyvinyl alcohol (PVA), being a dominant contributor of total organic carbon (TOC) in textile wastewater, is not easily degradable by conventional methods of wastewater treatment. This study investigates the degradation of aqueous PVA in a continuous UV/H2O2 photoreactor since the feeding strategy of hydrogen peroxide proves to have considerable effects on the process performance. Response surface methodology involving the Box-Behnken method is adopted for the experimental design to study the effects of operating parameters on the process performance. Experimental analysis shows that the TOC removal varies from 16.11 to 42.70 % along with a reduction of the PVA molecular weights from 56.7 to 95.3 %. The TOC removal is significantly lower than the molecular weight reduction due to the generation of the intermediate products during oxidation. Operating the UV/H2O2 process in a continuous mode facilitates the degradation of highly concentrated polymeric solutions using a relatively small hydrogen peroxide concentration in the feed with a small residence time ranges from 6.13 to 18.4 min.