Decomposition and detoxification of the insecticide thiacloprid by TiO₂‐mediated photocatalysis: kinetics, intermediate products and transformation pathways

Abstract

BACKGROUND: Pesticides are listed among the main environmental stressors directly correlated with severe impacts on ecosystems and human health. Here, the potential of TiO 2 -mediated photocatalytic oxidation of the insecticide thiacloprid, in aqueous media, is investigated thoroughly. RESULTS: Degradation was investigated under various operational conditions, including the initial concentration of the pesticide, the type and amount of catalyst, pH and the presence of electron acceptors. The prevalence of TiO 2 P25 in comparisonto the other titania employed, is obvious both in the case of decomposition and carbon mineralization. Twenty-seven transformation products generated during the photocatalytic decomposition of thiacloprid under UV-A irradiation were elucidated by high-resolution liquid chromatography mass spectrometry analysis, enabling the proposition of potential fragmentation pathways. The initial ecotoxicity of the insecticide determined by measurements of the bioluminescence of marine bacteria Vibrio fischeri was eliminated within 240 min of UV-A irradiation in the presence of TiO 2 P25. A phytotoxicity evaluation based on three eukaryotic plant species led to similar conclusions, resulting in the complete removal of phytotoxicity within 240 min of UV-A illumination in the presence of TiO 2 P25. CONCLUSIONS: These findings suggest that TiO 2 -mediated photocatalytic oxidation has the potential to efficiently detoxify water containing neonicotinoid pesticides.

Fluorocarbon Plasma Gas Passivation Enhances Performance of Porous Silicon for Desorption/Ionization Mass Spectrometry

“…Tandem mass spectrometry (MS/MS) analysis was able to detect the parent peak at m/z 253 as well as major fragments at m/z 186 and m/z 126 corresponding to [C 8 H 9 NClS] + and [C 6 H 5 NCl] + , respectively. 44 Analysis using an F 13 -silanized surface showed no difference in fragment peaks (Figure S9B).…”

“…Evaluation was performed by analyzing thiacloprid, a common pesticide present in the agriculture industry, directly from Surine (Figure B). Tandem mass spectrometry (MS/MS) analysis was able to detect the parent peak at m / z 253 as well as major fragments at m / z 186 and m / z 126 corresponding to [C 8 H 9 NClS] + and [C 6 H 5 NCl] + , respectively . Analysis using an F 13 -silanized surface showed no difference in fragment peaks (Figure S9B).…”

Treatment of Produced Water with Photocatalysis: Recent Advances, Affecting Factors and Future Research Prospects

“…The detection of intermediates can be achieved by conducting high-performance liquid chromatography with tandem mass spectrometry (LC-MS/MS) analysis, which can qualitatively and quantitatively determine the organic intermediates even at trace concentrations. Several research groups have studied the photochemical and photocatalytic degradation of various organic contaminants, including pharmaceuticals (e.g., ibuprofen, metoprolol) [40,86], insecticide (e.g., thiacloprid) [87], phenol [88], 4-chlorophenol [89], etc. To the best of our knowledge, to date, there is no study on the detection of intermediate products for produced water treatment.…”

Photo-Fenton and TiO2 Photocatalytic Inactivation of Model Microorganisms under UV-A; Comparative Efficacy and Optimization

“…Extensive research has been conducted aiming at the development of optimized homogeneous and heterogeneous photocatalytic approaches for the decomposition and detoxification of hazardous organic substances in aqueous solutions, such as antibiotics [ 13 , 15 , 16 , 17 ], pesticides [ 18 , 19 , 20 ] and dyes [ 21 , 22 , 23 , 24 ]. Similar studies have been conducted for the evaluation of the photocatalytic inactivation of microorganisms in suspension [ 25 ], focusing on endospores, considered to be one of the most resistant targets [ 12 , 26 , 27 ], viruses [ 28 , 29 , 30 ], fungi [ 14 ], Gram-positive and Gram-negative bacteria [ 31 ].…”