Photocatalyzed Degradation of a Pesticide Derivative Glyphosate in Aqueous Suspensions of Titanium Dioxide

Abstract

The photocatalytic degradation of a herbicide derivative, glyphosate [(N-phosphonomethyl) glycine] has been investigated in aqueous suspensions of titanium dioxide at different pH values. This compound was found to degrade more efficiently under alkaline pH, where no adsorption takes place on the surface of the catalyst in the dark. The main degradation route involves the cleavage of the P-C bond giving rise to sarcosine and glycine as the intermediate products formed during the photooxidation process.

Removal of glyphosate from water by electrochemically assisted MnO2 oxidation process

“…When the C-P bond was broken, glyphosate was decomposed to AMPA and acetic acid; when the C-P bond was broken, sarcosine and phosphoric acid were produced [10]. In a photocatalytic process, two possible pathways for glyphosate degradation were proposed under acidic (i.e., sarcosine formation) and basic (i.e., direct generation of glycine) pH conditions, respectively [20]. Therefore, the hydroxyl radicals generated in the electrochemical process may be responsible for a different pathway of glyphosate degradation in the electro-MnO 2 process.…”

Adsorption of Glyphosate on Resin Supported by Hydrated Iron Oxide: Equilibrium and Kinetic Studies

“…Improper disposal of this wastewater can lead to soil, groundwater, and surface water contamination. Various processes have been developed to treat glyphosate in wastewater, including advanced oxidation technologies (Chen et al, 2007;Huston and Pignatello, 1999;Manassero et al, 2010;Muneer and Boxall, 2008), biodegradation (Echavia et al, 2009;Lyliam et al, 2007) and adsorption (Gimsing and Borggaard, 2007;Khenifi et al, 2010;Li et al, 2005;Sheals et al, 2002). Recently, interest has increased in further development of adsorption technology.…”

Eletrochemical Oxidation of Herbicides

“…Degradation with chlorine led to higher efficiency, with almost complete removal of the contaminant. Munner and Boxall (2008) have investigated the photocatalytic degradation of GH in TiO 2 suspension with 12 black lamps of 15 W, using initial concentration of GH equal to 170 mg L -1 . Good degradation rates were achieved, and 90% GH removal was observed.…”