gamma-irradiation for the removal of atrazine in aqueous solution containing humic substances

The removal of atrazine from water containing humic substances by means of gamma-irradiation was studied. gamma-irradiation experiments were carried o ut under 4 different conditions: with continuous bubbling of N-2, O-2, N2O alone and N2O with O-2 (N2O/O-2 = 80/20) during irradiation. Some results w ere compared with those obtained using the combination O-3/gamma-irradiatio n. It was shown that atrazine is removed by both OH. and e(aq)(-). But opposit e to data from OH. radicals action, neither desethylatrazine nor deisopropy latrazine are major byproducts from e(aq)(-). The natural organic matter (h umic substances) content of the aqueous solution was characterized by 254 n m wavelength absorbance, total organic carbon, hydrophobicity and ultrafilt ration on 1000 D cutoff membranes. Results indicate that for a radiation do se of 800 Gy, which has been applied for atrazine removal, among the three species examined (i.e. OH., O-2(.-) and e(aq)(-)), mostly OH. and O-2(.-) l ead to organic matter properties changes. (C) 1999 Elsevier Science Ltd. Al l rights reserved.