Valorisation of original nanostructured lead oxides thin films issued from an innovating electrochemical depollution process: Application to the total electro-mineralisation of glyphosate

Abstract

Glyphosate is a very problematic pollutant in the world. This study presents a simple treatment to degrade it until total mineralisation with no production of AMPA (aminomethylphosphonic acid), its main by-product more toxic and persistent, by using original nanostructured lead oxides thin films. The synthesis conditions of these materials were determined previously in relation to an innovating electrochemical depollution process of water polluted by soluble lead. Different parameters were evaluated such as pH, initial concentration, lead oxide type and consequently its particular morphology. The solutions were systematically analysed by ion chromatography to determine the concentrations of organic pollutants and ionic species produced, and by UV–visible spectroscopy to quantify released lead during process. The thin films were characterized by XRD, SEM and EDS, before and after interaction. The Pb-04 sample type (pure β-PbO2 with cubic needles nanostructures) seems particularly efficient to obtain a total mineralisation with a mineralisation capacity equal to (1127 ± 56) mg of glyphosate/g of material. Moreover, lead was not released in solution due to a total regeneration with the similar crystalline structure. These results are very promising for potential valorisation of heavy metals wastes for future applications at room temperature and very low electrical inputs.