Aqueous Solution Certain Herbicides in Photocatalytic Decontamination
Abstract
Investigation were conducted to establish the photocatalytic effect on the degraduation of six different herbicides anilofos, alachlor, butachlor, azimsulfuron, metsulfuron methyl and sulfosulfuron using TiO2 as catalyst. For this purpose three different classes of herbicides (organophosphorus, organochlorine and sulfonyl urea) were studied. The study was mainly conducted in aqueous solutions. The influence of amount of TiO2, temperature, anionic and cationic agents, pH, surfactants and radiant flux were studied. The data generated clearly showed that the addition of TiO2 in terms of different quantities, highly influenced the degradation rate. The increase in temperature significantly increased the dissipation rate in the presence of TiO2 catalyst up to 70C. At different concentrations of the herbicides investigated, TiO2 quantity showed significant influence on the degradation rate. This was evident from the fact that 0.5 g/l of TiO2 showed optimum dissipation up to the level 20ug/ml. At higher concentration levels even though the dissipation was faster, the results showed the requirement of additional quantities of TiO2 as evidenced from the presence of residues.