A new application pattern for sludge-derived biochar adsorbent: Ideal persulfate activator for the high-efficiency mineralization of pollutants

Via enlarging the specific surface area of sludge biochar to enhance the close contact of multiple reactants may be a simple route to improve the catalytic performance with reduced dosage of biochar and oxidant, benefitting for cost-effectiveness and eco-friendliness. Herein, PS activation ability of a reported sludge-derived biochar adsorbent was investigated. 80% TOC of 100 mL 10 mg/L BPA was removed within 40 min by 7 mg biochar and 0.5 mM PS mixed, with a relatively high PS activation efficiency close to 50%. Expectedly, the desired mineralization efficiency of complex actual wastewater was also identified. Eco-friendliness of the application mode was confirmed by the leaching toxicity and acute bio-toxicity tests. Physicochemical properties of the sludge biochar were comprehensively characterized by various techniques. Combined with a series of mechanism analysis, center dot OH, SO4-, center dot O-2(-), O-1(2), free electron all participated in pollutants removal process and the non-radical pathway of electron transfer dominated the reaction. The generated metastable complex [SBC-PS*] confirmed by in situ FT-IR and Raman spectra was the most important active species for electron transfer and PS decomposition. Due to the high efficiency and stability, the sludge biochar adsorbent/PS catalytic system provides a promising way for waste reuse and advanced wastewater treatment.

Automated summary

By enlarging the specific surface area of sludge biochar, the catalytic performance can be improved with reduced dosage of biochar and oxidant, leading to cost-effectiveness and eco-friendliness. The combination of biochar and PS showed efficient removal of organic compounds in wastewater, confirming its environmental friendliness. The sludge biochar adsorbent/PS catalytic system provides a promising and efficient way for advanced wastewater treatment.