Silico-oxygen bonding integrated with nano-size pore enrichment enables sustainable low-oxidant-consumption Fenton-like chemistry.

Key bottlenecks of the persulfate-based advanced oxidation processes (AOPs) are the high dosage of persulfate and the secondary pollution of sulfate ion. In this work, a sustainable strategy involving the transformation of diatomite into a water purification catalyst consisting of nano-size pore enrichment and silico-oxygen bonding (Si/C@BD) was proposed. Results indicated that the pollutants with electron-donating groups can be quickly degraded by the Si/C@BD via amplified electron transfer process (ETP) under very low peroxymonosulfate (PMS) usage. Such "low-oxidant-consumption" Fenton-like chemistry can be also applied to other catalytic systems derived from a series of silicon-based materials. In addition, a pilot-scale device (54 L) based on ETP pathway was constructed, which provided a universal strategy to prevent direct contact of treated wastewater with oxidation additives, thereby solving the bottleneck of secondary pollution caused by sulfate dissolution associated with PMS oxidation systems. In addition, the Si/C@BD/PMS system exhibited the superior environmental significance and feasibility based on the quantitative analysis via the life cycle assessment (LCA). This work will be a significant contribution to the persulfate-based Fenton-like chemistry, emphasizing the low-persulfate-consumption and free-secondary-pollution characteristics with significant application value.