Red mud-based magnetic biochar composite as a peroxydisulfate activator for tetracycline degradation

Red mud is the world's most extensively generated waste in the non-ferrous metal industry. Its utilization remains challenging, with disposal primarily relying on storage. Due to its strong alkalinity, it poses significant environmental risks. This study investigated the potential for high-value utilization of red mud-based catalyst, WR800, which was obtained via a one-step calcination method of red mud and wheat straw at high-temperature. The material effectively activated peroxydisulfate and achieved 97.7 % degradation of TC (20 mg/L) within 60 min. Singlet oxygen (¹O₂) and hydroxyl radicals (•OH) were identified as the active species. WR800 exhibited well pH adaptability and resilience to common anions, addressing challenges in real-world wastewater treatment. Additionally, the magnetic properties of WR800 facilitated its easy recovery, and it retained the ability to degrade 99.9 % of tetracycline even after four regeneration cycles. Turning red mud and wheat straw into a sustainable catalyst provides a low-cost and environmentally friendly solution for treating water polluted with antibiotics and is in line with circular economy principles. This study shows possible potential for industrial use in reducing antibiotic contamination and provides an idea for industrial and agricultural waste disposal.