Fotolitička i fotokatalitička razgradnja odabranih herbicida u vodenoj sredini

Abstract

Ispitana je kinetika i mehanizam fotokatalitičke razgradnje herbicida kvinmeraka i klomazona u prisustvu UV/TiO2 Degussa P25, odnosno piklorama i klopiralida primenom UV/TiO2 Wackherr pri različitim eksperimentalnim uslovima. Praćena je i kinetika razgradnje odabranih herbicida direktnom fotolizom uz primenu sunčevog, UV i vidljivog zračenja, kao i u odsustvu svetlosti. Pored toga, upoređena je efikasnost UV/TiO2 Degussa P25, odnosno UV/TiO2 Wackherr sa vidljivim zračenjem, kao i direktnom fotolizom u prisustvu pomenutih izvora svetlosti. U cilju procene citotoksičnosti klomazona i klopiralida, kao i smeše klomazona i klopiralida i njihovih intermedijera nastalih tokom fotokatalitičke razgradnje ispitan je in vitro rast ćelijskih linija MRC-5 i H-4-II-E. Nakon ispitivanja fotokatalitičke razgradnje odabranih herbicida u dvaput destilovanoj vodi, praćena je njihova razgradnja i u prirodnim vodama. Takođe, ispitan je uticaj dodatka hidrogenkarbonata i huminske kiseline na efikasnost razgradnje odabranih herbicida. Fotokatalitička razgradnja klomazona, piklorama i mekopropa je ispitivana i u prisustvu UV/TiO2 nanocevi. Aktivnost katalizatora TiO2 Wackherr i TiO2 nanocevi je upoređena sa TiO2 Degussa P25.

The kinetics and mechanism of photocatalytic degradation of the herbicides quinmerac and clomazone in the presence of UV/TiO2 Degussa P25, and of picloram and clopyralid using UV/TiO2 Wackherr under different experimental conditions were studied. The kinetics of degradation of selected herbicides by direct photolysis using sunlight, UV and visible radiation, and in the absence of light were followed. In addition, the efficiencies of UV/TiO2 Degussa P25 and UV/TiO2 Wackherr were compared with visible radiation and direct photolysis in the presence of the above mentioned light sources. In order to evaluate the cytotoxicity of clomazone and clopyralid alone and in their mixture with intermediates formed during the photocatalytic degradation, in vitro growth of cell lines, MRC-5 and H-4-II-E was followed. After examining the photocatalytic degradation of selected herbicides in double distilled water, their decomposition in natural waters was also followed. Also, the influence of hydrogencarbonate and humic acid addition on the efficiency of degradation of selected herbicides was studied. Photocatalytic degradations of clomazone, picloram and mecoprop were investigated in the presence of UV/TiO2 nanotubes. Activities of the catalysts TiO2 Wackherr and TiO2 nanotubes were compared to TiO2 Degussa P25.