Preparation of CoFe2O4/MWNTs/sponge electrode to enhance dielectric barrier plasma discharge for degradation of phenylic pollutants and Cr(VI) reduction

CoFe2O4/MWNTs/sponge electrodes were prepared by co-adsorption of CoFe2O4 nanowires and multiwalled carbon nanotubes (MWNTs) onto a pure sponge, which were combined in a dielectric barrier discharge (DBD) plasma reactor to enhance discharge performance. The optimum concentration of CoFe2O4 nanowires contained in the CoFe2O4/MWNTs/sponge electrode was 0.5 g/L with a degradation rate of phenol of 98.52 % in 40 min. The CoFe2O4/MWNTs/sponge-DBD system significantly had the highest energy utilization efficiency with the tip discharge formed by CoFe2O4 nanowires and uniform discharge zone enlarged by modified sponge electrode. Further, phenol, hydroquinone, nitrobenzene, and p-nitrophenol as phenylic pollutants combined with hexavalent chromium (Cr(VI)) were treated simultaneously in CoFe2O4/MWNTs/sponge-DBD system. CoFe2O4 nanowires in DBD process formed photocatalytic and Fenton-like reaction could enhance phenylic pollutants degradation and Cr(VI) reduction. The synergistic removal effect between phenylic pollutants and Cr(VI) was discussed and the reaction mechanism in the CoFe2O4/MWNTs/sponge-DBD system was also explored.

Automated summary

The CoFe2O4/MWNTs/sponge electrodes were prepared by co-adsorption of CoFe2O4 nanowires and multiwalled carbon nanotubes onto a sponge, enhancing discharge performance in a dielectric barrier discharge plasma reactor. The system showed high energy utilization efficiency, efficient degradation of phenylic pollutants, and simultaneous removal of hexavalent chromium. Photocatalytic and Fenton-like reactions induced by CoFe2O4 nanowires contributed to the enhanced degradation and reduction processes.