Prussian blue analogues-derived zero valent iron to efficiently activate peroxymonosulfate for phenol degradation triggered via reactive oxygen species and high-valent iron-oxo complexes

Abstract

It is of great significance to develop the effective technique to treat phenol-containing wastewater. Herein, Fe-based prussian blue analogues-derived zero valent iron (ZVI) was successfully synthesized by one-step calcination method. Owing to high specific surface area and rich active sites, ZVI-2 possessed excellent performance in charge transfer. Notably, in comparison with conventional ZVI and Fe2+, ZVI-2 can effectively activate peroxymonosulfate (PMS) for achieving rapid degradation of phenol, and the highest removal efficiency of phenol reached 94.9% within 24 min. More importantly, developed ZVI-2/PMS oxidation system with good stability displayed strong anti-interference capability. Interestingly, Fe0 loaded on the surface of ZVI-2 can efficiently break the O–O bond of PMS to generate reactive oxygen species (i.e., SO4•−, OH•, O2•− and 1O2). As main adsorption sites of PMS, the existence of oxygen vacancy promote the formation of high-valent transition metal complexes (namely ZVI-2≡Fe4+=O). Under the combined action of reactive oxygen species and ZVI-2≡Fe4+=O, phenol can be eventually degraded into CO2 and H2O. The possible degradation pathways of phenol were also investigated. Furthermore, proposed ZVI-2/PMS oxidation system displayed great potential for application in the field of wastewater treatment. All in all, current work provided a valuable reference for design and application of Fe-based catalysts in PS-AOPs.