Electrochemical Monitoring of Methylparathion Degradation in an Acid Aqueous Medium in Presence of Cu(II)

Abstract

A study was undertaken to determine the effect of Cu(II) in degradation of methylparathion (o,o-dimethyl o,4-nitrophenyl phosphoriotioate) in acid medium. Initial electrochemical characterization of Cu(II) and methylparathion was done in an aqueous medium at a pH range of 2-7. Cu(II) was studied in the presence of different anions and it was observed that its electroactivity depends on pH and is independent of the anion used. Methylparathion had two reduction signals at pH < or = 6 and only one at pH > 6. The pesticide's transformation kinetic was then studied in the presence of Cu(II) in acid buffered aqueous medium at pH values of 2, 4, and 7. Paranitrophenol appeared as the only electroactive product at all three pH values. The reaction was first order and had k values of 5.2 x 10(-3) s(-1) at pH 2, 5.5 x 10(-3) s(-1) at pH 4 and 9.0 x 10(-3) s(-1) at pH 7. It is concluded that the principal degradation pathway of methylparathion in acid medium is a Cu(II) catalyzed hydrolysis reaction.

Efficient biodegradation of acephate by Pseudomonas pseudoalcaligenes PS-5 in the presence and absence of heavy metal ions [Cu(II) and Fe(III)], and humic acid

“…3). In addition to above, after 14 days, more than 90% increase in intensity in the peak at m/z 147 was observed, that was due to formation of ferric ion metal complex [Fe(N-P = O(S))], which further reduced to Fe(OH) 2 at m/z 89 and consistence with recent studies (Kumar et al 2015c, d;Manzanilla-Cano et al 2004, 2007Sarkouhi et al 2012Sarkouhi et al , 2016. Recent studies have revealed that phosphate can promoted the mineral dissolution, probably be due to the different affinities between metals Co [ Ni [ Cu) and phosphates (Manzanilla-Cano et al 2004, 2007Sarkouhi et al 2012Sarkouhi et al , 2016.…”

“…Formation of stable complex till 14th day at m/z 147 was due to strong interaction of iron with O and N donor sites of decomposed metabolite. These interactions were logical and expected as per HASB principle (Kumar et al 2015c, d;Manzanilla-Cano et al 2004, 2007Sarkouhi et al 2012Sarkouhi et al , 2016. The reason behind slow biodecomposition was the complex formation behavior of Fe(III) with acephate through N and O atoms of acephate.…”

“…There were the various reports regarding biodegradation organophosphorus pesticides including the methyl parathion, ethoprophos, and chlorpyrifos (Chai et al 2010;Kumar et al 2013Kumar et al , 2015aManzanilla-Cano et al 2004;Pinjari et al 2012;Ramu and Seetharamana 2014;Sarkouhi et al 2012Sarkouhi et al , 2016Wang et al 2010). Only a few reports are available on bacterial-promoted biodegradation of acephate (Chai et al 2010;Kumar et al 2015a;Pinjari et al 2012;Prasad et al 2013;Ramu and Seetharamana 2014;Wang et al 2010).…”

“…The reason behind slow biodecomposition was the complex formation behavior of Fe(III) with acephate through N and O atoms of acephate. Here, Fe(III) may form six membered ring through the O of P=O and C=O, which is kinetically as well as thermodynamically stable (Manzanilla-Cano et al 2004, 2007Sarkouhi et al 2012Sarkouhi et al , 2016.…”

Kinetic Study of the Biodegradation of Acephate by Indigenous Soil Bacterial Isolates in the Presence of Humic Acid and Metal Ions

“…The bacterial isolates were reconfirmed by molecular biotechnology. There were various reports regarding biodegradation of OPs, including methyl parathion, ethoprophos, and chlorpyrifos [16,17]. Only a few reports are available on the bacterial-promoted biodegradation of acephate [7,9,10,12].…”