Photocatalytic Detoxification of Some Insecticides in Aqueous Media Using TiO2 Nanocatalyst

Abstract

The present study was performed to fabricate a titanium dioxide (TiO2) nanocatalyst with proper characteristics for the removal of some insecticides (dimethoate and methomyl) from aqueous media. A TiO2 catalyst of regular (TiO2—commercial—/H2O2/UV) or nano (TiO2—synthesized—/H2O2/UV) size was employed as an advanced oxidation process by combining it with H2O2 under light. Moreover, the total detoxification of insecticides after treatment with the most effective system (TiO2(s)/H2O2/UV) was also investigated through exploring the biochemical alterations and histopathological changes in the liver and kidneys of the treated rats. Interestingly, the present study reported that degradation rates of the examined insecticides were faster using the TiO2 catalyst of nano size. Complete degradation of the tested insecticides (100%) was achieved under the TiO2(s)/H2O2/UV system after 320 min of irradiation. The half-life values of the tested insecticides under H2O2/TiO2(c)/UV were 43.86 and 36.28 for dimethoate and methomyl, respectively, whereas under the H2O2/TiO2(c)/UV system, the half-life values were 27.72 and 19.52 min for dimethoate and methomyl, respectively. On the other hand, no significant changes were observed in the biochemical and histopathological parameters of rats administrated with water treated with TiO2(s)/H2O2/UV compared to the control, indicating low toxicity of the TiO2 nanocatalyst-. Altogether, the advanced oxidation processes using TiO2 nanocatalyst can be considered as a promising and effective remediation technology for the complete detoxification of methomyl and dimethoate in water. However, further future research is needed to identify the possible breakdown products and to verify the safety of the used nanomaterials.