Novel Ag/Ni bimetallic-loaded sawdust-derived biochar as a periodate activator for the effective degradation of levofloxacin.

In this study, a novel silver/nickel-loaded sawdust-derived biochar (Ag/Ni-SDBC) was synthesized and employed as an efficient catalyst for periodate (PI) activation for the degradation of a fluoroquinolone antibiotic, namely levofloxacin (LEV), to tackle antimicrobial resistance. Although bimetallic-modified biochars have attracted increasing attention for advanced oxidation processes, their catalytic mechanisms remain poorly investigated. Moreover, to the best of our knowledge, this is the first study to investigate Ag/Ni-modified biochar for PI activation. LEV degradation by the Ag/Ni-SDBC/PI system was approximately 1.85, 1.35, and 1.15 times greater than that achieved by the SDBC/PI, Ag-SDBC/PI, and Ni-SDBC/PI systems, respectively. The optimum degradation performance was obtained at a PI concentration of 2 mM, an initial LEV concentration of 10 mg L-1, a catalyst dosage of 0.5 g L-1, and pH 7. The fabricated loaded biochar also demonstrated high reusability performance, with only an 8.79% decline in degradation efficiency after five consecutive reuse cycles. Mechanistic investigations identified singlet oxygen as the dominant reactive species, while no toxic iodinated by-products were detected. The degradation system maintained high degradation efficiency in the presence of the investigated inorganic ions, except HCO3 -. Its applicability was further validated in various water matrices, including real domestic and pharmaceutical wastewater, achieving total organic carbon mineralization efficiencies of 40.26% and 32.48%, respectively. A cost study revealed the economic feasibility of the system, yielding a positive net present value and a payback period of 4.3 years. Overall, the Ag/Ni-SDBC/PI system represents an efficient, reusable, and economically viable technology that can be promising for industrial wastewater treatment.