In recent years zeolite has been used as an amending material for arable soils because of its large cation exchange capacity. Thus, the cation adsorptive characteristics and the method of CEC determination were investigated. The sample used was a pulverized zeolite rock of tuffaceous origin occured in Itaya, Yamagata Prefecture, and was composed mainly of clinoptilolite.
The zeolite was saturated with NH
4+ by treating with ammonium acetate, and the adsorbed NH
4+ was extracted by centrifugal technique with KCl, NaCl, CaCl
2, A1C1
3 or acetic acid solutions. Although KCl solution extracted all of the adsorbed NH4+ with four extraction treatments, the other solution, especially CaCl
2, AlCl
3 and acetic acid, were inferior in the extrction of NH
4+to KCl. For example, even afted thirteen extraction treatments with CaCl
2, 17% of the adsorbed NH
4+ was still remained in the exchange site.
It was noticed from the results that either NH
4+ or K
+ should be used to saturating and extracting cations in the CEC determination of zeolite.
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