Mining iron from stainless steel pickling wastewater to produce quasi-MIL-100(Fe) for boosted photocatalytic peroxymonosulfate activation

Resource recovery for the preparation of high-value-added products represents a promising strategy for reducing pollution and carbon emissions. In this study, stainless steel pickling wastewater was utilized as a metal source to synthesize MIL-100(Fe), which was subsequently transformed into quasi-MIL-100(Fe) (Q350-MIL-100(Fe)) through controlled pyrolysis at an optimized temperature of 350 °C. The as-prepared Q350-MIL-100(Fe) demonstrated exceptional performance in activating peroxymonosulfate (PMS) under ultraviolet (UV) light irradiation, enabling the efficient degradation of various organic pollutants. Compared to pristine MIL-100(Fe), Q350-MIL-100(Fe) exhibited a 41.56-fold increase in the degradation rate constant for atrazine (ATZ), attributed to its narrower bandgap, abundant exposed active sites, and hierarchical porous structure. Furthermore, a self-constructed reactor employing Q350-MIL-100(Fe)/graphite felt (GF) as an immobilized catalyst achieved continuous and complete (100.0%) ATZ degradation for up to 96.0 hours. This work provides valuable insights into the sustainable utilization of industrial wastewater to produce high-value-added functional materials for environmental remediation, aligning with the dual goals of pollution control and resource recovery.