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The Surface Catalyzed Hydrolysis of Parathion on Kaolinite
Author(s) -
Saltzman Sarina,
Yaron Bruno,
Mingelgrin Uri
Publication year - 1974
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1974.03615995003800020012x
Subject(s) - hydrolysis , chemistry , kaolinite , parathion , adsorption , decomposition , catalysis , degradation (telecommunications) , inorganic chemistry , phosphate , chemical decomposition , thiophosphate , organic chemistry , mineralogy , pesticide , telecommunications , computer science , agronomy , biology
The decomposition of parathion on various monoionic kaolinites was investigated. The degradation was found to proceed via the hydrolysis of the phosphate ester to p‐nitrophenol and diethyl thiophosphate. The kaolinites were found to catalyze the hydrolysis. The nature of the exchangeable cation greatly affected the rate of hydrolysis. Ca‐kaolinite was the most active in inducing the degradation of parathion, the hydrolysis being twice as fast as in a water solution at pH 8.5 at the same temperature. The presence of a large excess of water decreased the catalytic effect of the kaolinite. The mechanism of the hydrolysis is via adsorption of the parathion upon the exchangeable cation or its hydration shell. The temperature dependence of the process is consistent with this proposed mechanism. The significant catalytic activity of kaolinites and its dependence on the exchangeable cation is important to the understanding of the degradation of parathion in soil and may be utilized in the formulation of parathion for various purposes.