S. Navarro García

Degradation catalytique du chlorfenvinphos et du methidathion deposes sur kaolinite et bentonite saturees par differents cations

Abstract The catalytic degradation of chlorfenvinphos and methidathion on H+, Ca+2, Na+ and ?+ monoionic kaolinite and bentonite was investigated. The results showed that the decomposition of chlorfenvinphos was greater than methidathion in both clays. The extent of degradation was influenced by the nature of the exchange cations and its degree hydration, in the following sequence: K+ >Na+ >Ca+2 >H+/A1+3. In both clays the process of hydrolysis occurred in two stages involving first‐order kinetics of differents hydrolysis rates. The first stage consisted a high hydrolysis rate of short duration and the second had a slow rate but involved a continuous hydrolysis.

Adsorption du chlorfenvinphos et du methidathion sur argiles saturees par differents cations

Summary Adsorption of chlorfenvinphos and methidathion from dissolutions on H+, Ca++, Na+ and K+ are studied. In all cases the saturating cation distinctly influenced the Freundlich‐type adsorption, with adsorption decreasing in the following sequence: H+> Ca++> Na+ > K+. Chlorfenvinphos adsorption was slightly greater than methidathion in two clays, and the adsorption extent for them in kaolinite is slower that bentonite.