Insights into the role of oxidation and adsorption for degradation of methyl parathion by ferrate (VI)

Methyl parathion (MP), as a widely used organophosphorus pesticide, posed a great threat for the aquatic environment because of its high toxicity and bioaccumulation. Ferrate (Fe(VI)) has received extensive attention in the environmental field in recent years as a green and efficient, multifunctional strong oxidant. In this study, Fe(VI) was used to degrade MP, and its performance and mechanism were comprehensively investigated. MP can be entirely eliminated within 5 min ([Fe(VI)] = 150 & mu;M, [MP] = 10 & mu;M and initial pH = 8.0). Moreover, Fe(VI) performed significantly better oxidation capacity than potassium permanganate and sodium periodate. MP degradation efficiency by Fe(VI) markedly improved with increasing Fe(VI) dosage or decreasing solution pH. And Cl , Ca2+ and Mg2+ exhibited negligible effects on MP degradation, while HA and HCO3  showed slightly inhibition. Fe(VI) and in situ formed iron nanoparticles contributed to the high removal of total organic carbon (TOC) mainly through oxidation and adsorption, achieving a maximum of 44%. Based on the nine by-products identified, three MP conversion pathways were proposed, and a significant reduction in the toxicity of Fe(VI)-degraded MP was detected with luminescent bacteria. With their unique advantages of multifunction in water treatment, Fe(VI) systems may be a viable method for the elimination of micropollutants.

Automated summary

This study investigated the degradation of methyl parathion using potassium ferrate. It was found that potassium ferrate has strong oxidation and adsorption abilities, and can completely degrade methyl parathion within a short period of time. Three conversion pathways of methyl parathion were proposed based on the identified by-products, and the toxicity of potassium ferrate-degraded methyl parathion was significantly reduced.