Bimetallic biochar-MOFs composites catalyzing peroxydisulfate in sulfadiazine removal

Sunflower seed husk is a common oil crop by-product. In this study, the husk was used as a base material for preparing a new catalyst, referred to as Fe-Cu-biochar-MOFs. The new material was characterized by multiple nanoscale metal clusters with rough surfaces and irregular shapes, thus providing abundant reactive surface area and sites. The catalytic reactivity was tested using sulfadiazine (SDZ) through batch kinetic experiments, where Fe-Cu-biochar-MOFs were used to activate peroxydisulfate (PDS). The results indicate that the system was able to degrade 95.9% of SDZ within 60 minutes. Mechanistic investigations revealed that the presence of PDS converted Fe-0 to Fe2+ and Cu-0 to Cu+ in the Fe-Cu-biochar-MOFs, and the resulting Fe(II) and Cu(I) ions facilitated the activation of PDS, resulting in abundant reactive oxygen species (O-1(2), SO4 center dot- and center dot OH). This work provides a new approach of using waste agricultural by-products for the removal of environmental pollutants.