Heterogeneous Photocatalytic Degradation of Disulfoton in Aqueous TiO₂ Suspensions: Parameter and Reaction Pathway Investigations

Abstract

The photocatalytic degradation of organophosphorus insecticide disulfoton is investigated by having titanium dioxide (TiO 2 ) as a photocatalyst. About 99% of disulfoton is degraded after UV irradiation for 90 min. The effects of the solution pH, catalyst dosage, light intensity, and inorganic ions on the photocatalytic degradation of disulfoton are also investigated, as well as the reaction intermediates which are formed during the treatment. Eight intermediates have been identified and characterized through a mass spectra analysis, giving insight into the early steps of the degradation process. To the best of our knowledge, this is the first study reporting the degradation pathways of disulfoton. The results suggest that possible transformation pathways may involve in either direct electron or hole transfer to the organic substrate. The photodegradation of disulfoton by UV/TiO 2 exhibits pseudo-first-order reaction kinetics and a reaction quantum yield of 0.267. The electrical energy consumption per order of magnitude for photocatalytic degradation of disulfoton is 85 kWh/(m 3 order).

Enhanced photoreactivity of MOFs by intercalating interlayer bands via simultaneous NCO and SCu modification

“…NO 3 − can further inhibit the degradation effect. In addition to the reaction of NO 3 − with ROS (Equations and ), 75 its larger size can cover more active sites of the catalyst 76 . HCO 3 − can produce the maximum inhibitory effect, mainly because the CO 3 2− generated by HCO 3 − and ·OH can quickly remove ROS in the reaction (Equations ) 74 .…”

“…In addition to the reaction of NO 3 À with ROS (Equations 6 and 7), 75 its larger size can cover more active sites of the catalyst. 76 HCO 3 À can produce the maximum inhibitory effect, mainly because the CO 3 2À generated by HCO 3 À and ÁOH can quickly remove ROS in the reaction (Equations 8-10). 74 Excessive CO 3 2À ions will also lead to excessive negative charges on the surface of the material, affecting the degradation.…”

Mobility and degradation of disulfoton in coffee culture soil

“…Later, Szeto et al (1983), reintroduced this degradation pathway for a sandy soil. Chen et al (2013) proposed a route to disulfoton, in which the degradation was induced by ultraviolet radiation in aqueous suspension of TiO 2 . These studies also detected DST, degradation products, namely disulfoton sulfoxide (DSO) and disulfoton sulfone (DSA) and also their oxygen analogues (AODSO and AODSA), indicating that the permanence of this active ingredient in the environment can be longer than one would expect for an organophosphate.…”

A green approach to the synthesis of 2,3‐diaminophenazine using a photocatalytic system of CdFe2O4/TiO2 nanoparticles

“…TiO 2 -based photocatalysts have shown an excellent photocatalytic activity in various applications due to their good photochemical and chemical stability as well as superior light absorption. [10][11][12][13][14] In addition, magnetic nanoparticles (MNPs) are very interesting due to their multiple properties such as size effects, surface-to-volume ratio, magnetic separation, specificity, low toxicity, and the ability to control exposure and surface chemistry. Reducing and controlling exposure and hazard leads to low environmental risk.…”