Hydroxyapatite supported Co3O4 catalyst for enhanced degradation of organic contaminants in aqueous solution: Synergistic visible-light photo-catalysis and sulfate radical oxidation process

Abstract

Through dispersing Co3O4 into a 3D flower-like OV-HAp (Oxygen Vacancies Hydroxyapatite) support, Co3O4@OV-HAp was facilely obtained and the agglomeration of Co3O4, as well as the leaching of Co2+ were efficiently inhibited. With both PMS (peroxymonosulfate) and visible-light presented, Co3O4@OV-HAp was used as a heterogeneous catalyst for model dye Rh B (Rhodamine B) degradation in which visible-light was introduced to be another activation source for ROSs (Reactive Oxygen Species) generation except for PMS. The catalytic reaction parameters were optimized and the concentrations of Co as well as the possible co-existent metal ions were all determined by ICP-OES (inductively coupled plasma optical emission spectrometer) and ICP-MS (inductively coupled plasma mass spectrometer) individually. The synergistic effect between visible-light photo-catalysis and SO4•- oxidation process greatly enhanced the catalytic activity of Co3O4@OV-HAp for Rh B degradation, and 100% Rh B can be degraded compared with only 5% by Co3O4. Moreover, the degradation rate was also greatly increased to about 212-fold higher in comparison with Co3O4.