Scalable Preparation of High-Performance Sludge Biochar with Magnetic for Acid Red G Degradation by Activating Peroxymonosulfate

The sludge pyrolysis technology for biochar production delivers dual environmental benefits, addressing both sludge disposal challenges and enabling environmental remediation through the utilization of the resultant biochar. However, the complex multi-step procedures and low catalyst output in previous studies constrain the practical implementation of this technology. A facile sludge pyrolysis method was constructed to achieve the batch production of municipal sludge biochar (MSB) in this study. Compared to municipal sludge (MS), the resultant MSB showed a higher BET surface area, more well-developed pore channel architecture, and plentiful active sites for activating peroxymonosulfate (PMS). Under the optimized conditions (CMSB = CPMS = 0.2 g/L), 93.34% of Acid Red G (ARG, 20 mg/L) was degraded after 10 min, posing an excellent rate constant of 0.278 min−1. Additionally, MSB demonstrated excellent broad pH adaptability, ion interference resistance, reusability, and recyclability for ARG elimination. It was primary Fe sites that excited PMS to generate O2•− and Fe-oxo species (FeIV=O) for ARG degradation. The reaction process exhibited minimal heavy metal leaching, indicating limited environmental risk. Therefore, the practical applicability of the sludge biochar production, coupled with its scalable manufacturing capacity and exceptional catalytic activity, collectively demonstrated that this study established a viable pyrolysis methodology for municipal sludge, offering critical insights for sludge disposal and resource reutilization.