Effect of dry density pH on the diffusion behavior of lanthanum in compacted Chinese GMZ bentonite

Abstract : Diffusion experiments in compacted GaoMiaoZi (GMZ) bentonite were performed with La(III) using the in-diffusion method, the effects of dry density pH were emphasized. The apparent diffusion coefficient (D (a)) was obtained at the end of the experiment. D (a) decreases with increasing dry density of 1.3-1.7 Mg m(-3) as well as slightly decreases as pH increases from 3.6 to 8.9. The D (a) range is (2-16) x 10(-12) m(2) s(-1) under the experimental conditions. The distribution coefficients (K (d)) for La(III) in compacted GMZ bentonite are much smaller than those on powdered bentonite obtained from batch experiments.