Peroxydisulfate activation by sulfur-doped ordered mesoporous carbon: Insight into the intrinsic relationship between defects and 1O2 generation

The carbon-catalyzed persulfate-based advanced oxidation process (PS-AOP) has recently received much focus owing to the green, economical, and sustainable nature of carbon catalysts. In this study, sulfur-doped ordered mesoporous carbons (S-OMCs) were utilized to activate peroxydisulfate (PDS) for ciprofloxacin (CIP) removal. A synthesis temperature gradient was set to regulate the defect level of S-OMCs, since the thermal decomposition of oxygen- and sulfur-containing groups at different temperatures could release S and 0 and then create defects. In all S-OMCs/PDS systems, O-1(2) dominated CIP degradation. Interestingly, a high linear correlation (R-2 = 0.9091) between defect level and O-1(2) yield was found, confirming the structure-activity relationship between defects and O-1(2) generation. Moreover, the impacts of several important reaction conditions and water matrix on S-OMC-1000/PDS activation system were surveyed. In the S-OMC-1000/PDS activation system, CIP removal could attain 85.84% under the condition of unadjusted pH (pH = 5.3) and small amount of S-OMC-1000 (50 mg/L). The SOMC-1000/PDS activation system also exhibited relatively stable or even better performance in the presence of common inorganic anions and natural organic matter (NOM), manifesting its good potential for practical applications. In addition, the reusability of S-OMC-1000 was investigated. This study provides a practical and high-efficiency way for decontaminating antibiotic-polluted water, and gives an alternative approach for identifying the active site of catalysts.

Automated summary

The carbon-catalyzed persulfate-based advanced oxidation process (PS-AOP) has gained attention for its green and economical nature. Sulfur-doped ordered mesoporous carbons (S-OMCs) were used to activate peroxydisulfate (PDS) for ciprofloxacin (CIP) removal. The study found a correlation between defect level and O-1(2) yield, and investigated the impact of various reaction conditions and water matrix. The S-OMC-1000/PDS activation system showed promising results for CIP removal, even in the presence of common inorganic anions and natural organic matter (NOM).