Photoelectrocatalyzed degradation of organophosphorus pesticide fenamiphos using WO3 nanorods as photoanode

Abstract

In this study, WO3 nanostructures were synthesized by the electrochemical anodization technique to use them on the degradation of persistent organic compounds such as the pesticide fenamiphos. The acids electrolyte used during the anodization were two different: 1.5 M H2SO4 -0.05 M H2O2 and 1.5 M CH4O3S -0.05 M H2O2. Once the samples have been manufactured, they have been subjected to different tests to analyze the properties of the nanostructures. With Field Emission Scanning Electron Microscopy (FE-SEM) the samples have been examined morphologically, their composition and crystallinity has been studied through Raman Spectroscopy and their photoelectrochemical behaviour by Photoelectrochemical Impedance Spectroscopy (PEIS). Finally, degradation tests have been carried out using the technique known as photoelectrocatalysis (PEC). The conditions that were applied in this technique were a potential of 1 VAg/AgCl and simulated solar illumination. The degradation process was monitored by UV-Visible and High-Performance liquid Chromatography (HPLC) to control the course of the experiment. The nanostructures obtained with 1.5 M CH4O3S -0.05 M H2O2 electrolyte showed a better photoelectrochemical behaviour than nanostructures synthesized with 1.5 M H2SO4 -0.05 M H2O2. The fenamiphos degradation was achieved at 2 hours of experiment and the intermediate formation was noticed at 1 hour of PEC experiment.

Anodizing Tungsten Foil with Ionic Liquids for Enhanced Photoelectrochemical Applications

“…Then, due to the acidic electrolyte, fluoride ions encouraged localized dissolution of the formed WO 3 layer and developed soluble fluoride complexes [ 36 ]. Specifically, methanesulfonic acid can excellently solubilize metal salts and it is an environmentally friendly electrolyte [ 43 ].…”

Eliminación de pesticidas organofosforados mediante fotoelectrocatálisis con fotoánodos de WO3

“…Los auxocromos son los grupos funcionales unidos a los cromóforos (son la parte de la molécula responsable para impartir color o los grupos funcionales que contienen múltiples enlaces capaces de absorber radiación por encima de 200 nm debido a la transiciones π/ π* y n-π*) que modifican su capacidad para absorber luz, alterando la longitud de onda o la intensidad de absorción hacia longitudes de onda más largas. Por tanto, la banda intermedia aparece en longitudes de onda más bajas que la banda principal de fenamifos, ya que este intermedio ha perdido los auxocromos (uno o ambos de los auxocromos) que confieren ese aumento en la longitud de onda registrada [139]. Para ello, se analizaron 4 patrones con la misma concentración que los patrones analizados mediante UV-Vis para hallar la recta de calibrado correspondiente y poder relacionar el valor del área obtenida en cada muestra con la concentración de fenamifos.…”

Photoelectrocatalysis for high-value-added chemicals production

“…Compared with the aforementioned, the treatment of organic pollutants contained in medical and agricultural wastewater is more difficult, because most of this type of organic pollutants have the ability to resist chemical and biological degradation processes [103], or its strong toxicity may cause great physiological impact on organisms even if its concentration in wastewater is very low [104,105]. For example, the widespread antibiotic tetracycline hydrochloride (TCH) has high stability in the environment.…”