Phenol Conversion and Dimeric Intermedia

This study investigates the removal of phenol from water using horseradish peroxidase-catalyzed polymerization. The objective was to identify reaction products and evaluate the reaction kinetics. The methodology involved experimental assessment of phenol conversion at varying concentrations, determination of dimeric and trimeric intermediates through NMR spectroscopy, and analysis of the reaction rates with respect to substrate concentrations. Results indicated that over 95% of phenol was removed from an initial concentration of 188 mg/L, with the presence of five dimeric and one trimeric product in the aqueous solution. Notably, p-phenoxyphenol was determined to be the optimal substrate for peroxidase activity with a specific reaction rate of 2.172 nM-l min-l. The findings revealed that polymerization bonds were predominantly oxygen-para connections, while ortho-ortho connections were rare in larger oligomers. A peroxidase inactivation model was proposed, demonstrating a logarithmic relationship between the inactivation rate constant and the ratio of polyethylene glycol to enzyme doses, substantiating the kinetic behavior observed during phenol conversion. Overall, this study contributes to understanding enzymatic processes for pollutant removal in water treatment applications.