Fabrication of a 3D-blocky catalyst (CoMnOx@sponge) via mooring Co-Mn bimetallic oxide on sponge to activate peroxymonosulfate for convenient and efficient degradation of sulfonamide antibiotics

An elastic and 3D-blocky catalyst (CoMnOx@sponge) was successfully prepared via uniform growth and distribution of Co-Mn bimetallic oxide inside the sponge for the activation of peroxymonosulfate (PMS). The results showed that 30 mg/L sulfisoxazole (SIZ) could be completely degraded by PMS (1 mM) activated with CoMnOx@sponge (0.1 g/L) within 5 min. The pseudo-first-order rate constant was calculated to be 1.83 min−1, which was much larger than those from previous reports. The excellent stability and reusability of CoMnOx@sponge were confirmed through 20 recycle runs with more than 90% degradation of SIZ and less than 0.9 mg/L leached metal ions. Singlet oxygen (1O2), hydroxyl radicals (•OH) and sulfate radicals (SO4•−) were determined to be the dominating reactive oxygen species (ROS) responsible for the degradation of SIZ. The possible pathways of SIZ degradation as well as underlying catalytic mechanism were deduced. The bio-toxicity declined obviously after the mineralization of SIZ and the removal of TOC at 5 mg/L SIZ was high up to 90.4%. Furthermore, the system of CoMnOx@sponge/PMS also exhibited the strong anti-interference ability in natural water and the universal degradation capacity towards other common organic pollutants. More remarkably, the 3D-catalyst possessing an elasticity and extremely high porosity could be easily assembled with a column to realize the consecutive degradation of pollutants. The labor- and time-saving removal of pollutants based on a combination of CoMnOx@sponge with PMS makes it great potential in practical application.