Electrochemical behaviour and degradation of methyl parathion on platinum electrode

Abstract

Methyl parathion adsorption from the solution of 0.5 M H2SO4 (M = mol dm−3) on the surface of platinum electrode has be proven. When Pt electrode covered by adsorbed product is cycled between potentials of 0.4 V to −0.23 V, the split of adsorbed molecules of methyl parathion occur and molecules of p-nitrophenol are released. We assume that molecules of methanol are also released besides p-nitrophenol and molecules of methylthiophosphoric acid remain adsorbed on the surface of the platinum electrode. If oxidation of adsorbed product is realized by cycling between potentials of −0.23 V to 1.32 V, the split of adsorbed molecules of methyl parathion occur and molecules p-nitrophenol and methanol are released. The adsorbed methylthiophosphoric acid is completely mineralized. Degradation of methyl parathion was observed in the electrochemical cell with separated electrode compartments. After 12 h of cycling between potentials of −0.23 V to 1.32 V, the concentration of the methyl parathion decreased to 2.5% of starting value (5.3 × 10−5 M).