The effect of ozonation on the degradation of carbaryl in aqueous solution.

The aim of this study is to investigate the synergetic effect of ozonation on ultraviolet irradiation on the degradation of carbaryl (CBL) (1-naphthyl-N-methylcarbamate) in aqueous solutions (40 mg L-1). The degradation of CBL and the intermediates formed during ozonation were determined by gas chromatography-mass spectrometer. The change in formaldehyde, dissolved oxygen, pH, and total acidity were determined as a function of ozonation time. It was found that the dissolved oxygen and total acidity were increased with the increasing ozonation time but the pH was decreased with the increasing ozonation time. The aliphatic acids formed during ozonation were followed by ion chromatography as a function of ozonation time. It was found that the effect of ozonation is highly effective on the degradation of CBL. The complete degradation of CBL has occurred at 75-second ozonation time. As a consequence of the obtained results the possible degradation pathway was proposed. The results confirmed that ozonation is an effective method for the degradation of CBL.