Fast oxidation of the neonicotinoid pesticides listed in the EU Decision 2018/840 from aqueous solutions

Neonicotinoid pesticides family is nowadays identified as the most important type of insecticides in the world.Their consequent widespread occurrence in the environment represents not only a wellknown risk for bees but also a significant negative impact in aquatic ecosystems.In this work, the capability of catalytic wet peroxide oxidation (CWPO) (Fe 3 O 4 -R400/H 2 O 2 ) as a low-cost and environmentally-friendly system for the treatment of the neonicotinoid pesticides listed in the EU Watch List (Decision 2018/840) (acetamiprid (ACT), clothianidin (CLT), imidacloprid (IMD), thiacloprid (THC) and thiamethoxam (THM)) has been investigated.Remarkably, complete elimination of the pollutants (1000 g L -1 ) and the aromatic by-products was reached in 20 min reaction time operating at 25 ºC, 1 atm, and pH 0 = 5, with the stoichiometric H 2 O 2 amount (~4 -5 mg L -1 ) and 1 g L -1 catalyst load.The reactivity order of the insecticides decreased as follows:THC>IMD>THM>CLT>ACT, being the pseudo-first order rate constant values within the range of 0.26 -0.61 min -1 .Notably, high mineralization yields were obtained (>50%), being the final effluents non-toxic.As example, the oxidation pathway of ACT was proposed.Finally, the catalytic system was tested in real surface water.