Effect of light on humic substances : production of reactive species

Abstract

Under photochemical excitation, humic substances produce reactive species which can degrade a great variety of organic compounds. Solvated electrons, hydroxyl radicals, singlet oxygen and reactive triplet states were characterized using probe molecules and scavenging techniques. The quantum yield of formation of these species depends on the irradiation wavelength, on oxygen concentration and on the origin of the humic substances. Through their photoinductive properties, humic substances can be used to degrade pollutants.