A Quantitative Method for the Determination of Montmorillonite in Soils*

Rachel Levy and C. W. Francis
Agricultural Research Organization, The Volcani Center, P.O.B. 6, Bet Dagan, Israel
* Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel. 1974 Series, No. 224-E. Part of the Work was carried out at the Environmental Sciences Division, ORNL, Oak Ridge, Tennessee. Sponsored by NSF/RANN grant EATC through the Interagency Agreement NS FAG 389 with Union Carbide Co.
Soil Scientist, A.R.O., The Volcani Center, Bet Dagan, Israel and Environmental Sciences Div., ORNL, Oak Ridge, Tennessee, respectively.

Abstract: A quantitative method for determination of montmorillonite in the soil clay fraction, using X-ray spectrometry, is proposed. The method is based on the fact that polyvinylpyrrolidone (PVP) is adsorbed on the interlayer surfaces of montmorillonite, giving a first order c-axis spacing of 26 Å, while it is not adsorbed on other swelling clays. The experimental conditions to obtain a maximum height of the X-ray diffraction peak, and the effect of the mass adsorption coefficient of vermiculite on the intensity of montmorillonite, were investigated. Soil montmorillonite was determined by the method of known additions, measuring the intensity of the X-ray diffraction peak before and after the addition of small and known amounts of Wyoming montmorillonite.

Clays and Clay Minerals; May 1975 v. 23; no. 2; p. 85-89; DOI: 10.1346/CCMN.1975.0230201
© 1975, The Clay Minerals Society
Clay Minerals Society (www.clays.org)