Design and application of an up-scaled dielectric barrier discharge plasma reactor for regeneration of phenol-saturated granular activated carbon

Abstract

An integrated granular activated carbon (GAC) adsorption and dielectric barrier discharge (DBD) plasma degradation process was applied for treatment of organic wastewater. A methodology of scaling up the DBD plasma reactor was proposed, and a technique for regenerating GAC using the up-scaled DBD reactor driven by bipolar pulsed power has been achieved. The mass of exhausted GAC being treated was 1200g in each experimental process. The feasibility of GAC regeneration using the up-scaled reactor was systematical assessed by monitoring the GAC regeneration efficiency (RE) and phenol degradation on GAC at different operational parameters, such as pulse voltage, treatment time, air flow rate and water content of GAC. Under the optimized conditions (pulse voltage of 21kV, treatment time of 60min, air flow rate of 0.45m3/h and GAC water content of 31%), RE and the phenol degradation reached 94% and 70%, respectively. After four adsorption–regeneration cycles, RE was still 32% higher than RE of untreated exhausted GAC. FTIR analysis proved the phenol decomposition on GAC after DBD treatment. In addition, TOC and COD removal of adsorbed phenol on GAC reached 49% and 58%, respectively. Effect of DBD plasma on the texture characteristic of GAC after several adsorption–regeneration cycles were investigated by adsorption of N2 and Boehm titration. The results suggest that the up-scaled DBD reactor for GAC regeneration is feasible, and this technique for wastewater treatment provides us with an optimistic outlook for the practical application of this process.