Evaluation of Energy Balance in a Batch and Circulating Non-thermal Plasma Reactors During Organic Pollutant Oxidation in Aqueous Solution

This work presents the treatment of an organic waste solution using gliding arc plasma in moist air, which is an excellent source of oxidizing species. Herein particular attention is devoted to the comparative energy balance between two model reactors in order to optimize the process and get closer to a large-scale application. The model pollutant Amoxicillin is an antibiotic agent largely used against allergies and has been found in wastewaters. Its degradation is studied by exposing basic solutions to underline the role of the formed (OH)-O-center dot radicals and H2O2 reactive species. The degradation of AMX to give CO2, H2O, and sulfate is optimized within 120min with a resulting abatement of 78% and 98% for batch and circulation reactors respectively. The kinetic study suggests a pseudo-first order process with an apparent rate constant three times higher in circulation mode compared to batch mode reactor. Accordingly, the energetic yield is 2.5 times better in the circulation system, owing to more consumption of plasma-generated species with respect to the high reactive area, whereas in batch mode reactor, AMX degradation is occurred at the plasma-liquid interface, and thus limited by the mass transfer process.