Electroenzymatic mineralization of 2-chlorobiphenyl in synthetic wastewater

An electroenzymatic method is developed to degrade 2-chlorobiphenyl (2-CB) with horseradish peroxidase (HRP) immobilized glassy carbon electrode as the working electrode. Cyclic voltametric studies were carried out to understand the redox reactions involved. An applied potential of −0.5 V was found suitable for the degradation of 2-CB. During degradation, dechlorination of 2-CB was confirmed by the measurement of chloride ion concentration in the reaction mixture, and was found almost equimolar to the initial 2-CB concentration. Chloride concentration was 0.53 ppm at the end of reaction while the initial 2-CB concentration was 3.15 ppm. That means that almost 97% of the chlorine in 2-CB sample was liberated. Total organic carbon (TOC) measurements revealed that almost 83% 2-CB was mineralized. Degraded products were analyzed by GC-MS to find reaction intermediates. However, no peak could be detected except 2-CB. Therefore, the most probable route of degradation is through dechlorination followed by biphenyl ring cleavage and mineralization.