Anodic Oxidation of the Insecticide Imidacloprid on Mixed Metal Oxide (RuO₂-TiO₂and IrO₂-RuO₂-TiO₂) Anodes

Abstract

In this work, we evaluated the performance of the Ti/RuO2-TiO2 and Ti/RuO2-IrO2-TiO2 electrodes as electrocatalytic materials in the degradation of the insecticide imidacloprid (ICP). The temperature and current density operating parameters were investigated, and the degradation was followed by measurements of TOC and by UV-Vis spectroscopy. The complete oxidation de ICP (100% mineralization) was achieved by applying 40 mA cm−2 when Ti/RuO2-TiO2 or Ti/RuO2-IrO2-TiO2 were used at 60°C during 2 or 3 h electrolysis, consuming 33.3 kWh m−3 and 47.5 kWh m−3 of energy, respectively. Raising the temperature promoted a significant change in the results compared to those obtained at 25°C. TOC removal, mineralization current efficiency and electric charge data indicated a system operating under mass transport control. The ICP absorption spectra showed suppression of the peak at 265 nm and increasing the peak at 214 nm, with the electrolysis time, indicating breakdown of the insecticide's molecular structure and formation of short chain compounds, before its complete mineralization. Degradation process occurred via direct anodic oxidation and Cl2-mediated oxidation. The study showed that the electrochemical degradation process using DSA anodes is feasible and can be a good alternative for removing the insecticide in water or sewage treatment plants.

Electrochemical Oxidation of Atrazine and Clothianidin on Bi-doped SnO2–TinO2n–1 Electrocatalytic Reactive Electrochemical Membranes

“…The primary oxidation mechanisms during EAOPs are direct electron transfer and reaction with OH • . Past research has shown that electrochemical oxidation could completely mineralize ATZ , and imidacloprid (a similar neonicotinoid insecticide to CDN). , However, these studies required extended reaction times and/or elevated temperatures (e.g., 60 °C) to achieve mineralization.…”

Methiocarb Degradation by Electro-Fenton: Ecotoxicological Evaluation

“…Among these new treatment technologies, electrochemical processes have been widely studied, mainly due to their high efficiency in the degradation of recalcitrant compounds [3,[5][6][7]. Silva et al [8] achieved complete oxidation of the insecticide imidacloprid, at a concentration of approximately 25 mg L −1 , by applying an anodic oxidation (AO) process with mixed metal oxide anodes. Successful degradation of the herbicides monolinuron, paraquat, and clopyralid and of the pesticide profenofos, at concentrations ranging 10-100 mg L −1 , by electro-Fenton (EF), was also reported [2,[9][10][11].…”

Polyaniline-Grafted RuO2-TiO2 Heterostructure for the Catalysed Degradation of Methyl Orange in Darkness

“…This is an important economical aspect given the cost of ruthenium-based compounds. Due to these salient features, the conducting RuO 2 -TiO 2 heterostructure is explored in the development of supercapacitors [23], electrode for chlorine electrogeneration [28] as well as pigments, fillers, electro-resistor films for electrodes, or dielectric device catalyst supports [29,30].…”