Removal of Polyvinyl Alcohol Using Photoelectrochemical Oxidation Processes Based on Hydrogen Peroxide Electrogeneration

摘要

This study investigates the removal efficiency of PVA from aqueous solutions using UV irradiation in combination with the production of electrogenerated hydrogen peroxide (H_2O_2) at a polyacrylonitrile-based activated carbon fiber (ACF) cathode. Three cathode materials (i.e., platinum, graphite, and ACF) were fed with oxygen and used for the electrogeneration of H_2O_2. The amount of electrogenerated H_2O_2 produced using the ACF cathode was five times greater than that generated using the graphite cathode and nearly 24 times greater than that from platinum cathode. Several parameters were evaluated to characterize the H_2O_2 electrogeneration, such as current density, oxygen flow rate, solution pH, and the supporting electrolyte used. The optimum current density, oxygen flow rate, solution pH, and supporting electrolyte composition were found to be 10 mA cm~(-2), 500 cm~3 min~(-1), pH 3, and Na_2SO_4, respectively. The PVA removal efficiencies were achieved under these conditions 3%, 16%, and 86% using UV, H_2O_2 electrogeneration, and UV/H_2O_2 electrogeneration, respectively. A UV light intensity of 0.6 mW cm~(-2) was found to produce optimal PVA removal efficiency in the present study. A simple kinetic model was proposed which confirmed pseudo-first-order reaction. Reaction rate constant (k_(ap)) was found to depend on the UV light intensity.