Cooperation of multi-walled carbon nanotubes and cobalt doped TiO2 to activate peroxymonosulfate for antipyrine photocatalytic degradation

A hybrid catalyst system consisted of MWCNT and Co-TiO2 through simple physical mixing was applied for peroxymonosulfate activation for antipyrine degradation. With 2 mM peroxymonosulfate, the removal rate of antipyrine is significantly increased from 53.24% and 86.23% to 100% in the presence of same weight of 0.2 g/L MWCNTs, Co-TiO2, and MWCNTs/Co-TiO2 (half/half) mixture, respectively in 12 min. The influence of various parameters, including the ratio of Co-TiO2/MWCNT, catalyst dose, peroxymonosulfate dose, antipyrine concentration, and initial pH, were further investigated in detail. The underlying catalytic mechanism of the synergistic effect was unraveled by quenching tests and EPR analysis. It was attributed to the electrons tranferration between Co-TiO2 and MWCNT, and the acceleration of Co3+/Co2+ by generated superoxide. This work not only provides a novel and efficient method of pharmaceutical wastewater treatment, but also reveals a new perspective to use the catalyst more efficiently.

Automated summary

The study investigated a hybrid catalyst system of MWCNT and Co-TiO2 for antipyrine degradation, which significantly increased the degradation rate. By exploring different parameters, the synergistic effect of the catalyst system was revealed, showing electron transfer and acceleration of Co3+/Co2+ as key factors.