“…Advanced oxidation process using hydroxyl radicals has been found as an alternative and efficient tool for the treatment of various organic pollutants. Among these processes, Fenton processes such as conventional Fenton process [1,[6][7][8][9], photo-Fenton [8,9], sono-Fenton [10,11], electro-Fenton (EF) [12][13][14][15][16][17], helielectro-Fenton [18], sono-photo-Fenton [10], photo-electro-Fenton [19,20], etc., received great attention during recent years. Except EF process, other Fenton processes require the external addition of hydrogen peroxide for the production of hydroxyl radicals.…”