Wang, et al (2024) Discrepant Catalytic Activity of Biochar-Based Fe and Co Homonuclear and Heteronuclear Diatomic Catalysts for Activating Peroxymonosulfate to Degrade Emerging Pollutants. ACS ES&T Engineering. https://doi.org/10.1021/acsestengg.4c00096

In a recent study published by ACS ES&T Engineering, researchers explored the catalytic capabilities of biochar-based iron (Fe) and cobalt (Co) catalysts in degrading emerging organic pollutants through the activation of peroxymonosulfate (PMS). The study introduced two types of catalysts: homonuclear (DAC–Fe–Co) and heteronuclear (DAC-Fe/Co) diatomic catalysts, prepared by modifying the ligands of Fe and Co in biocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More.

The research findings revealed that an acid pretreatment of biochar was essential for the successful synthesis of these atomic catalysts. Interestingly, while DAC-Fe/Co contained higher levels of Fe and Co, it exhibited lower catalytic activity compared to DAC–Fe–Co. Specifically, the DAC–Fe–Co was significantly more effective, with its rate constant for degrading sulfamethoxazole (SMX) being 4.1 times greater than that of DAC-Fe/Co.

Both types of catalysts activated PMS to produce similar reactive species, including radicals and non-radicals. However, DAC–Fe–Co generated a higher concentration of radicals, contributing to its superior performance. Density functional theory (DFT) calculations supported these observations, showing that DAC–Fe–Co had a higher adsorption capacity for PMS and lower energy barriers for the regeneration of active sites in Fe and Co. This enhanced regeneration is likely what led to the faster removal rates of SMX in the DAC–Fe–Co/PMS system.

Additionally, the DAC–Fe–Co/PMS system demonstrated high resistance to inorganic anions and maintained excellent catalytic stability throughout cycling experiments. This research not only underscores the distinct catalytic efficiencies between homonuclear and heteronuclear diatomic catalysts but also presents a novel approach for preparing effective homonuclear diatomic catalysts for environmental remediation.