Peroxymonosulfate activation using heterogeneous catalyst Sr2FeO4 coated on SBA-15 for efficient degradation of antibiotic sulfapyridine.

It is significant to explore the advanced oxidation process (AOP) for antibiotic degradation. Herein, a peroxymonosulfate (PMS) activator, Sr2FeO4/SBA-15 (SFS) heterogeneous catalyst, was synthesized by in situ growth of Sr2FeO4 on the surface of SBA-15. In SFS/PMS catalytic system, Sr atom provided electrons to Fe(II) ↔Fe(III) ↔Fe(II) redox cycle through Sr-O-Fe bonds for PMS activation. The SFS catalyst could activate PMS to generate a free radical coexistence system, including sulfate radical (SO4∙-) and hydroxyl radicals (∙OH). The catalyst possessed high catalytic activity and high stability. The degradation efficiency of sulfapyridine (SAD) over the SFS/PMS catalytic system could reach 99.0% after 90 min reaction. After the 5th reuse, the degradation efficiency of SAD was still more than 94.0%, and the phase structure of the catalyst did not alter. The low ion leaching concentration would be more conducive to reuse and avoiding secondary pollution, in comparison to homogeneous catalysts. This catalyst can be widely applied to organic wastewater treatment.-->.