Photo Catalytic Applications of Zinc Oxide Nanorods for the Analysis of Chlorimuron Herbicide Residues in Water by LC-MS/MS

Photo Catalytic Applications of Zinc Oxide Nanorods for the Analysis of Chlorimuron Herbicide Residues in Water by LC-MS/MS

Zinc oxide (ZnO) nanorods having the size 100 to 250 nm diameters and 1 to 2 μm length were used as photo-catalyst for the decontamination of sulfonylurea urea herbicide chlorimuron in water. The study was conducted in milli Q water, at three different buffer solutions of pH 4.0, 7.0 and 9.0 under direct sunlight at two different concentrations. The optimum concentration of catalyst required for the complete degradation was established as 0.1 g l-1. The degradation of herbicide in neutral pH water was faster when compared with acidic and basic pH solutions in presence of ZnO catalyst. The influence of cations (Fe2+, Cu2+ and Ni2+) anions (ClO4-, Cl-, CO32-) had shown no significant degradation, but Fe2+ contributed positively to the degradation. Influence of surfactant was studied with cetyltrimethylammonium bromide (CTAB), sodium decyl sulfate (SDS) and Brij-35. The presence of surfactant SDS showed slight increase in the degradation rate. Residues, breakdown products were quantified and confirmed by liquid chromatography electro spray tandem mass spectrometry (LC-ESI-MS/MS). The method has the limit of quantification 0.1 μg/L in water. The dissipation of residues showed first order kinetics, DT 50 and DT 90 were calculated from the dissipation data.