Decontamination of aqueous glyphosate, (aminomethyl)phosphonic acid, and glufosinate solutions by electro-fenton-like process with Mn2+ as the catalyst.
The ability of the modified electro-Fenton-like (EF-like) process to degrade aqueous solutions of glyphosate, which is the most widely used herbicide in the world, has been assessed with Mn(2+) and other metal ions as catalysts to overcome the problems posed by some stable metal ion complexes of phosphonate herbicides. Bulk electrolyses with a carbon-felt cathode and Pt anode were performed in an undivided cell under galvanostatic conditions to study the effect of the applied current as well as Mn(2+) and glyphosate concentrations. The herbicide was completely destroyed in all cases following a pseudofirst-order kinetics, and the second-order rate constant for its reaction with (*)OH was determined. The decay trends obtained by high-performance liquid chromatography-fluorometric detection (HPLC-FL) and ion chromatography analysis were similar. AMPA [(aminomethyl)phosphonic acid] was the major reaction intermediate and showed slower pseudofirst-order destruction kinetics. The high mineralization degree obtained for glyphosate solutions confirmed the great performance of the EF-like process with Mn(2+), which promotes the C-N cleavage by (*)OH attack as the first oxidation step and the C-P cleavage in a further step. High-level decontamination achieved for AMPA and glufosinate solutions corroborated the benefits of this oxidation process.
Laboratoire Géomatériaux et Geologie de l'Ingenieur, Université Paris-Est, Marne-la-Vallée Cedex 2, France.
Beytul
B
Balci
Mehmet A
MA
Oturan
Nihal
N
Oturan
Ignasi
I
Sirés
D000613:Aminobutyrates / Q000737:chemistry*; D002384:Catalysis; D003666:Decontamination / Q000379:methods*; D005998:Glycine / Q000031:analogs & derivatives* / Q000737:chemistry; D006540:Herbicides / Q000737:chemistry*; D007700:Kinetics; D008345:Manganese / Q000737:chemistry*; D009943:Organophosphorus Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D000097797:Glyphosate
D000613:Aminobutyrates; D005998:Glycine; D006540:Herbicides; D008345:Manganese; D009943:Organophosphorus Compounds; D014874:Water Pollutants, Chemical; D000097797:Glyphosate; C036423:1-aminomethylphosphonic acid; C003121:phosphinothricin