Treatment of 4-chlorobenzoic acid by plasma-based advanced oxidation processes

Studies show that oxidation resistant pollutants are present after conventional water treatment systems. Nowadays a new class of oxidation processes is studied: advanced oxidation processes. Our process is based on the use of an electrical discharge (Glidarc and DBD) to produce HO, which is generated on the surface of a thin film of water. The first results show that the DBD is more efficient than the Glidarc with a degradation efficiency of the target pollutant (4-chlorobenzoic acid (pCBA)) of about 0.87 g kWh−1 for DBD and 0.16 g kWh−1 for gliding arc discharge. However, it appears that secondary reactions due to corrosion of the metallic micro-structured plate cause slower degradation of the pollutant. Moreover, the presence of nitrates in solution after treatment indicates the formation of NOx in the discharge and the possible formation of nitrogenous oxidation by-products.