Photocatalytic degradation of lindane, p,p′-DDT and methoxychlor in an aqueous environment

Aqueous solutions containing 40 mg/dm(3) of lindane,p,p'-DDT and methoxychlor were photodegraded in a UV/TiO2/O-2 system yielding different degradation products. Powdered anatase and rutile, and anatase supported on glass hollow microspheres served as photocatalysts. The destruction degree of pesticides was evaluated and oxidation products identified by gas chromatography with an electron capture detector (GC-ECD) and a mass spectroscopy detector (GC-MS). From 68 to 90% of pesticides investigated was eliminated after 30 min irradiation in the presence of anatase supported on glass microspheres. The lowest efficiency was obtained for rutile as a catalyst. One hundred and fifty minutes of processing resulted in 50% elimination for gamma-HCH, 85% for DDT and over 99% for methoxychlor. (C) 2000 Elsevier Science S.A. All rights reserved.