Fixation of Zinc by Clay Minerals
- M. R. Reddy and
- H. F. Perkins
Samples of bentonite, illite, and kaolinite clays were studied for their Zn fixation properties under various pH levels, alternate wetting and drying conditions, and incubation at moisture saturation. Bentonite and illite fixed significant quantities of Zn under wetting and drying. Fixation was directly related to pH and the amount of Zn added. Incubation of treated samples at moisture saturation resulted in approximately half the amount of Zn fixed as when subjected to repeated wetting and drying. Kaolinite fixed relatively small amounts of Zn as compared to bentonite and illite regardless of treatment.
Since X-ray and DTA did not reveal mineralogical change, it is concluded that Zn was fixed as a result of precipitation, physical entrapment in clay lattice wedge zones, and/or strongly adsorbed at the exchange sites. Cation exchange capacity (CEC) values were inversely related to Zn fixation.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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