Bifunctional copper cathode induced oxidation of glycerol with liquid plasma discharge

Treatment of glycerol, the byproduct from biodiesel production, calls for a more efficient and cost-effective approach. In this work, in situ hybrid induced oxidation method was proposed, involving the advanced oxidation process and electro-catalytic process. Generally, these highly active species in the plasma region is helpful to degrade the organic products. In addition, numerous CuO nanoparticles with oxygen defects that were induced by the plasma, could improve the catalytic performances. In the plasma discharge process, those CuO catalysts and plenty of hydrogen bubbles which were generated around the copper cathode, also resulted in the high efficiency dehydration of glycerol. The effects of discharge status of liquid plasma and glycerol volume on conversion rate were discussed in detail. It was found that a lower discharge voltage 70 V in the normal glow discharge period is beneficial to dehydration of glycerol. Combined with the FTIR analysis for products composition, the degradation products and the conversion rate were illustrated using the HPLC. The experimental results showed it can achieve a conversion rate of 81.27% after 40 min and the energy yield was 10.02 g/(kW h).