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United States Department of Agriculture

Agricultural Research Service

Title: Organoclays and Organohydrotalcites As Sorbents for Polar Pesticides

Authors
item Celis, R - IRNAS-CSIC SEVILLA SPAIN
item Hermosin, M - IRNAS-CSIC SEVILLA SPAIN
item Koskinen, William
item Cornejo, J - IRNAS-CSIC SEVILLA SPAIN

Submitted to: Crop Production and Protection Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: January 21, 2000
Publication Date: N/A

Technical Abstract: The sorption and desorption of the anionic herbicide imazamox by organoclays (alkylammonium-exchanged montmorillonite) and organohydrotalcites (alkylsulfate-exchanged hydrotalcite) was compared with that of the neutral fungicide triadimefon, to test the potential use of these sorbents for decontamination purposes and slow release formulations as related to their charge characteristics. The effect of pH on sorption was also investigated. Interlayered organoclays and organohydrotalcites were at least six times more sorptive for triadimefon than the untreated minerals, with higher sorption on organoclays at low pH levels. The nature and amount of organic ion in the interlayers influenced both triadimefon sorption and the extent of triadimefon desorption from organoclays and organohydrotalcites. For imazamox anion, sorption was greater on organoclays than on organohydrotalcites or the untreated minerals. Imazamox sorption on the organoclays was highly irreversible. Imazamox sorption, as well as the reversibility of the sorption-desorption process, increased with decreasing pH, due to protonation and further sorption of molecular imazamox species. The results of this work indicate that the diverse sorbents assayed may find application as filters in water decontamination for imazamox anion and as filters and supports for slow release formulations in the case of molecular imazamox and triadimefon.

Last Modified: 7/25/2014
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