Microwave-assisted persulfate/peroxymonosulfate process for environmental remediation

Sulfate radical (SO4 center dot-) generation from activated persulfate (PS) and peroxymonosulfate (PMS) processes has been receiving considerable attention in the field of environmental remediation. Because SO4 center dot- has superior oxidation potential (E-0 = 2.5-3.1 V) than other oxidants, non-selective response to organic pollutants, wide operational pH range and longer life time (30-40 mu s). Microwave (MW) irradiation (frequency from 0.3 to 300 GHz) has also gained a significant attention in environmental applications such as waste management and treatment including pyrolysis, water/wastewater treatment, phase separation and extraction processes, remediation of soil, hazardous and radioactive wastes and also in biomedical applications. The coupling of MW/PS processes is capable to generate high rate of sulfate radical as a result of the polar coupling, rapid and uniform heating, thermal and non-thermal effects. Further, the addition of transitional metal-based catalysts and dielectric nonmetal catalysts in the MW/PS system was found to improve the oxidation efficiency of the system. In this review, the fundamentals and applications of MW activated persulfate/peroxymonosulfate (MW/PS or MW/PMS) process for environmental remediation of various systems including wastewater containing pharmaceuticals, different dyes, phenolic compounds, contaminated soil, and leachate treatment have been discussed. Moreover, the mechanism and recent developments in MW/PS and MW/PMS systems in the presence/absence of catalysts have been highlighted. Finally, a hybrid technical approach from futuristic development was addressed.

Automated summary

The generation of sulfate radicals and the use of microwave irradiation have gained attention in environmental remediation. Sulfate radicals have superior oxidation potential and microwave irradiation offers rapid and uniform heating. The combined use of microwave activation and persulfate/peroxymonosulfate processes can efficiently degrade organic pollutants. This review discusses the fundamentals, applications, and recent developments in this field, including the use of catalysts to enhance the oxidation efficiency.