Effect of light on humic substances: Production of reactive species

Under photochemical excitation, humic substances produce reactive species w hich can degrade a great variety of :organic compounds. : Solvated electron s, hydroxyl radicals, singlet oxygen and reactive triplet states were chara cterized using probe molecules: and scavenging techniques. The quantum yiel d of formation of these species depends on the irradiation wave-length,on o xygen concentration and on the origin of the humic substances, Through thei r photoinductive properties, humic substances can be used to degrade pollut ants.