Kinetic analysis of the hydrolysis of methyl parathion using citrate-stabilized 10 nm gold nanoparticles. (February 2016)

• Record Type: Journal Article
• Authors: Nita, Rafaela; Trammell, Scott A.; Ellis, Gregory A.; Moore, Martin H.; Soto, Carissa M.; Leary, Dagmar H.; Fontana, Jake; Talebzadeh, Somayeh F.; Knight, D. Andrew
• Is Part Of: Chemosphere. Volume 144(2016)
• Page Start: 1916
• Page End: 1919
• Publication Date: 2016-02
• Subjects: Methyl parathion -- Degradation -- Gold nanoparticles -- Catalysis; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2015.10.036
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: "Ligand-free" citrate-stabilized 10 nm gold nanoparticles (AuNPs) promote the hydrolysis of the thiophosphate ester methyl parathion (MeP) on the surface of gold as a function of pH and two temperature values. At 50 °C, the active surface gold atoms show catalytic turnover ∼4 times after 8 h and little turnover of gold surface atoms at 25 °C with only 40% of the total atoms being active. From Michaelis–Menten analysis, k cat increases between pH 8 and 9 and decreases above pH 9. A global analysis of the spectral changes confirmed the stoichiometric reaction at 25 °C and the catalytic reaction at 50 °C and mass spectrometry confirmed the identity of p -nitrophenolate ( PNP ) product. Additional decomposition pathways involving oxidation and hydrolysis independent of the formation of PNP were also seen at 50 °C for both catalyzed and un-catalyzed reactions. This work represents the first kinetic analysis of ligand-free AuNP catalyzed hydrolysis of a thiophosphate ester. Highlights: "Ligand-free" 10 nm gold nanoparticles promote the hydrolysis of the methyl parathion. Catalysis on the surface of gold was measured as a function of temperature and pH. At 50 °C, the surface gold atoms show catalytic turnover ∼4 times after 8 h.