Abstract: Hydroxyl radical (·OH) is the most active and aggressive molecule with very high reaction rate constant, electronegativity and strong oxidation electrode potential. The advanced oxidation technology using ·OH as oxidant has broad application prospects. Starting from the production method and basic principle of ·OH, the principles, advantages and disadvantages of Fenton method, Electro-Fenton method, ultraviolet catalytic oxidant method, ultrasonic oxidation method and other compound methods are introduced. Finally, the application progress and limitations of the above methods in wastewater treatment, soil remediation, landfill leachate treatment, heavy metal complex treatment and ultra-precision processing of optical materials are reviewed.

Key words: hydroxyl radicals, advanced oxidation, Fenton, environmental protection, ultra-precision machining