TITLE:
Mechanism of Diazinon Adsorption on Iron Modified Montmorillonite
AUTHORS:
Ponyadira Kabwadza-Corner, Naoto Matsue, Erni Johan, Teruo Henmi
KEYWORDS:
Pesticide; Diazinon; Adsorption
JOURNAL NAME:
American Journal of Analytical Chemistry,
Vol.5 No.2,
January
17,
2014
ABSTRACT: The study was carried
out with the objective of developing suitable and sustainable low cost
adsorbent materials for diazinon, an organophosphate pollutant used as a
pesticide. Montmorillonite modified with iron was used. Two different types of
iron-montmorillonite, each having different contents of iron and synthesized
with different pH and levels of Fe hydrolysis were used. One was denoted “Fe-modified” and the other denoted as “FeOH-modified”.
The color of the samples changed from greyish green to light-reddish brown after
the modification. X-ray diffraction and physical observations were used for characterization of the samples. The
d-spacing of the samples was greater than 15 ?, indicating the formation of
iron hydroxides in the interlayer space of montmorillonite. The amount of
adsorption was calculated from the difference between the initial and the final
concentration of diazinon. The adsorption data were analyzed using the Langmuir
adsorption isotherms. The amounts of diazinon adsorbed were 58.8 and 54.1
mmolkg-1 for Fe-modified and FeOH-modified respectively. The steep
rise in their adsorption isotherms indicated the possibility of adsorption for
low level of diazinon in polluted water.