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Photodegradation of Imidacloprid Insecticide by Ag-Deposited Titanate Nanotubes: A Study of Intermediates and Their Reaction Pathways

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journal contribution
posted on 31.12.2014, 00:00 by Inderpreet Singh Grover, Satnam Singh, Bonamali Pal
The present work demonstrates the influence of Ag-loading (0.2–1.0 wt %) onto sodium titanate nanotubes (TNT) for complete photomineralization of the neurotoxic imidacloprid (IMI) insecticide under UV light illumination. It has been observed that degradation of IMI follows pseudo-first-order kinetics, where 0.5 wt % Ag-loaded TNT exhibited highest apparent rate constant (2.2 × 10–2 min–1) and corresponding least half-life (t1/2) of 31 min for IMI relative to bare P25-TiO2 (3.4 × 10–3 min–1, t1/2 = 230 min). The mineralization of IMI intermediates to CO2 during its photooxidation has been described by time course GC-MS and GC analysis and has been correlated with the kinetic analysis. The investigation for the role and quantitative estimation of the fate of heteroatoms (N, O, and Cl) present in IMI revealed an increase in the amount of nitrate, nitrite, and chloride ions with time during its photooxidation. On the basis of these results a mechanistic pathway for photomineralization of IMI is proposed.