Influence of colloid suspensions of humic acids on the alkaline hydrolysis of N‐methyl‐N‐nitroso‐p‐toluene sulfonamide

Abstract

The influence of humic substances (HSs) upon the alkaline hydrolysis of N-methyl-N-nitroso-p-toluene sulfonamide has been studied. Important inhibition of hydrolysis reaction has been reported. This inhibition has been explained in terms of association of reactants to the humic substances. Kinetic results have been modeled using the micellar pseudophase model. C

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

“…2). It attributed to the aggregation mechanism in the presence of humic acid (Arias-Estevez et al 2008;Astray et al 2010;Albers et al 2009;Brigante et al 2009;Mazzeia et al 2013;Mazzei and Piccolo 2012;Piccolo and Celano 1994). That is why only 75% acephate was decomposed up to 14 days as confirmed by ESI-MS analyses (Fig.…”

“…Taking into account that humic acids in water solution are micelle-like aggregates, these kinetic results have been rationalized in terms of micellar pseudo phase model (Arias-Estevez et al 2008;Astray et al 2010). These observations are explained with the establishment of weak interactions between organophosphorus pesticides and humic molecular superstructures and represent evidence of host-guest complex formation (Smejkalova and Piccolo (2008); Smejkalova et al (2009)).…”

“…A similar kind of fact on soils was proved by Chai et al 2010 with other mechanism; they mentioned that mineralization process can decrease on humic acid rich soils. Humic acid is a polymeric molecule having number of groups (election rich/poor) including NH, COOH, CO, OH, etc., and it can bind with xenobiotics or pesticides through the various mode of bonding (Arias-Estevez et al 2008;Astray et al 2010;Albers et al 2009;Brigante et al 2009;Mazzeia et al 2013;Mazzei and Piccolo 2012;Piccolo and Celano 1994). In the aggregation mechanism, variable adsorption of the organophosphorus pesticides on humic substances considerably depends on their macromolecular structure and leads to the formation of relatively stable complexes (Albers et al 2009;Mazzei and Piccolo 2012) (Fig.…”

“…Humic compounds are known as colloids that interact with pesticides through the hydrogen bonding, charge transfer, hydrophobic bonding, and van der Waals bonding to form complexes of various stabilities (Arias-Estevez et al 2008;Brigante et al 2009;Mazzeia et al 2013;Mazzei and Piccolo 2012;Piccolo and Celano 1994). High aggregation of the humic molecules with acephate content was probably due to an increasing extent of hydrogenbonding interactions between the P=O and C=O groups of acephate and humic polymer (Arias-Estevez et al 2008;Astray et al 2010;Albers et al 2009;Brigante et al 2009;Mazzeia et al 2013;Mazzei and Piccolo 2012;Piccolo and Celano 1994). In recent studies, very slow aggregation rate at pH 4 and 5 has been noticed and the rate was sharply increased by increasing pH (*8), where complete aggregation achieved in 30 min (Brigante et al 2009;Mazzeia et al 2013;Mazzei and Piccolo 2012;Piccolo and Celano 1994).…”

Pseudophase Model in Microemulsions

“…The pseudophase model applied to micelles has also been satisfactory for the analysis of the kinetic results in more complex micellar systems such as mixed micellar-cyclodextrin systems [31][32][33][34][35][36][37] or pseudo-micellar humic acids aggregates [38][39][40][41][42].…”