Fabrication of bimetallic MOF with 2D nanosheets structure and rich active sites for enhanced removal of organic pollutants by activation of peroxymonosulfate

Due to the fast and high oxidation efficiency for organic pollutants, it is extremely challengeable to develop efficient catalysts for peroxymonosulfate (PMS) to enhance the removal efficiency of pollutants. Herein, we fabricated a bimetallic MOF (CuCo-ABDC) by a facile hydrothermal process, which displayed 2D nanosheets structure and rich active sites. The characterization results showed that CuCo-ABDC-4 with Cu:Co ratio of 1:1 synthesized via temperature gradient ((100 ℃, 24 h) + (150 ℃, 12 h)) had low-crystalline but high catalytic performance towards PMS. With orange G (OG) as the model organic pollutant, CuCo-ABDC-4 displayed the highest catalytic activity for activation of PMS, where 96.4% of OG removal efficiency was achieved within 60 min via a rate constant of 0.052 min−1. The excellent catalytic activity can be attributed to the high density and uniformly distributed unsaturated Co(II) which was considered to be the main active site, and the interaction between Co and Cu species in the bimetallic MOF. The quenching experiments indicated the production of SO4•−, ·OH, and 1O2 in CuCo-ABDC-4/PMS system and 1O2 acted as the predominant reactive species for degradation of OG. Moreover, the presence of NO2−, H2PO4−, SO42−, HCO3− and HA exhibited evident inhibition on the OG degradation rate. On the contrary, the existence of CO32− could promote the OG degradation due to the production of carbonate radical. This work introduces a novel and facile fabrication strategy to attain 2D nanosheets structure bimetallic catalysts with high catalytic performance for activation of PMS in wastewater treatment.