| Popis: |
Organobentonites with dodecyltrimethylammonium chloride (DTMA) and hexadecyl trimethyl ammonium chloride (HTMA) were prepared and used as carrier of diazinon, with purpose to provide controlled release properties to the formulation containing diazinon. The structure of organobentonites was characterized by FTIR and XRD and the sorption towards diazinon was investigated, to reveal the effects of organobentonites on the release of diazinon. It was showed that organobentonites with quaternary alkylammonium were of excellent sorption capacity towards diazinon, in which hydrophobic interaction played a key roll. An enhancement of sorption could be achieved by increasing the alkyl chain length and the loading level of modifying agent. The release of diazinon was greatly reduced by organobentonites. The time taken for 50% of active ingredient to be released, T50, from organobentonites with DTMA loading of 75, 100 and 125% of the cation exchange capacity were 45.9, 40.2 and 38.0 times of the value for the formulation without organobentonites, respectively. Those for the release from organobentonites with HTMA of the same loading level were 73.2, 63.2 and 52.1 times. The difference of diazinon release may be related to the change in the structure of organobentonites and the interaction with diazinon. An increase in loading level of quaternary ammonium could produce a faster release of diazinon, while the extension of the alkyl chain slowed down the release. |
