Degradation of the insecticides Thiamethoxam and Imidacloprid in aqueous solution as promoted by an innovative Feº/Fe3O4 composite

Abstract

The performance of an innovative Feº/Fe 3 O 4 composite to degrade the insecticides Thiamethoxam and Imidacloprid in aqueous solution was evaluated. Factorial designs were built to investigate the influence of a number of crucial variables on such degradation processes: H 2 O 2 concentration, solution pH, and composite mass. The solution pH was the most influential variable; hence, significant degradation rates (> 90%) was accomplished exclusively in acidic solutions (pH=2). In addition, the composite was highly efficient in promoting the degradation of both insecticides either in the presence or unpredictably in the absence of H 2 O 2 . These results thus indicated that the composite possess a dual behavior, acting as either an oxidizing or a reducing agent.

Degradation of food dyes by zero-valent metals exposed to ultrasonic irradiation in water medium: optimization and electrospray ionization mass spectrometry monitoring

“…42 The influence of two variables, i.e., the exposure time to the ultrasonic irradiation (t US ) and the mass of metal (iron: m Fe ; tin: m Sn ), as well as their interactions, was thus established. The experiments were carried out in a random order.…”

Degradation of Thiamethoxam in aqueous solution by ozonation: Influencing factors, intermediates, degradation mechanism and toxicity assessment

“…To minimize its toxicity, an efficient method seems very necessary. We have observed that a few authors have investigated the degradation of THIA by methods such as direct photolysis (de Urzedo et al, 2007), photocatalysis (Mir et al, 2013), methods involving Fe/Fe 3 O 4 composites (de Urzedo et al, 2009), reactive oxidative species , immobilized TiO 2 ( Zabar et al, 2012), and zero-valent metals under ultrasonic irradiation (Lopes et al, 2008). However, studies about degradation of THIA by ozonation were little.…”

Degradation of herbicide diuron in water employing the Fe0/H2O2 system

“…[13][14][15][16] It has also been used for pesticide degradation in the last years. [17][18][19] Diuron degradation has been studied by different processes such as photo-Fenton, photocatalytic and biodegradability experiments and microbiologycal degradation. [15][16][17][18][19][20][21] Zero-valent iron has been used to be an effective material for the removal of a variety of important organic contaminants from water.…”

“…[17][18][19] Diuron degradation has been studied by different processes such as photo-Fenton, photocatalytic and biodegradability experiments and microbiologycal degradation. [15][16][17][18][19][20][21] Zero-valent iron has been used to be an effective material for the removal of a variety of important organic contaminants from water. 17,22,23 The redox couple formed by zero-valent iron (Fe 0 ) and dissolved aqueous Fe 2+ has a standard reduction potential of -0.440 V. 24 This makes Fe 0 a reducing agent for many redox-labile substances, including hydrogen ions, carbonate, sulfate, nitrate and oxygen.…”

“…[15][16][17][18][19][20][21] Zero-valent iron has been used to be an effective material for the removal of a variety of important organic contaminants from water. 17,22,23 The redox couple formed by zero-valent iron (Fe 0 ) and dissolved aqueous Fe 2+ has a standard reduction potential of -0.440 V. 24 This makes Fe 0 a reducing agent for many redox-labile substances, including hydrogen ions, carbonate, sulfate, nitrate and oxygen. 18,[24][25][26] The aim of this study was to optimize, develop and implement a simple, cheap and efficient method for diuron residue degradation.…”