title: Natural phillipsite as a matrix for a slow-release formulation of oxamyl.
abstract: The performance of phillipsite as a matrix for slow-release formulation of oxamyl [N,N-dimethyl-2-methylcarbamoyl-oxymino-2-(methylthio)acetamide] was tested. The adsorption kinetics followed a first-order law, and the adsorption isotherm fitted well in a two-surface Langmuir model, suggesting a double mechanism of interaction between oxamyl and the sorbent. The sorption mechanism, studied by FTIR, provided two fractions of oxamyl. The first one is sorbed on the mineral surface, linked by H-bonding, and the second one is constituted by a multilayer of oxamyl molecules linked by a water bridge between them. The release kinetics of oxamyl from a substratum zeolite-oxamyl also follows a first-order law, with two stages that correspond to both fractions of oxamyl previously detected.
authors.affiliation: Department of Pedology and Geology, University of La Laguna, 38204 La Laguna, Canary Islands, Spain.
authors.forename: J E
authors.initials: JE
authors.lastname: García Hernández
authors.forename: J S
authors.initials: JS
authors.lastname: Notario del Pino
authors.forename: M M
authors.initials: MM
authors.lastname: González Martín
authors.forename: R
authors.initials: R
authors.lastname: Díaz Díaz
authors.forename: E J
authors.initials: EJ
authors.lastname: Febles González