Iron-Modified Functional Biochar Activates Peroxydisulfate for Efficient Degradation of Organic Pollutants

Tetracycline (TC) contamination in wastewater presents a significant global environmental challenge, with conventional water treatment methods often proving ineffective at eliminating antibiotic pollutants. As a result, there is an urgent need for cost-effective and efficient remediation technologies. In this study, we utilized the abundant and low-cost Eichhornia crassipes as a precursor to prepare sulfuric acid-modified functional biochar (SC-Fe) through a two-step pyrolysis process. This SC-Fe was then employed to activate peroxydisulfate (PDS) for the removal of TC from wastewater. The structural and physicochemical properties of SC-Fe were extensively characterized, and its efficiency in activating PDS for TC degradation was evaluated. The results demonstrated that the SC-Fe/PDS system effectively removed 99.36% of TC within 60 min under optimal conditions (0.3 g/L SC-Fe, 5 mM PDS, initial pH 7.09, and 25 °C). The outstanding removal efficiency can be attributed to the high specific surface area, large porosity, and defect-rich structure of SC-Fe. Furthermore, during the TC removal process, the SC-Fe/PDS system generated SO4•−, •OH, and 1O2, with SO4•− and •OH acting as the primary reactive species. The high catalytic efficiency and low consumption of the SC-Fe/PDS system present a promising strategy for effective wastewater treatment.