摘要：

Cadmium sorption by montmorillonite from solutions in the 15 to 120 ppb range was studied in the presence of increasing concentrations of NaClCO/sub 4/, NaCl, and Na/sub 2/SO/sub 4/ solutions. The ionic strengths ranged from 0.01 to 1.00. Increasing ionic strengths decreased the amount of Cd sorbed on the clay surfaces. The percentage sorbed decreased from around 90 percent for l = 0.01 to about 50 percent for l = 1.00 in the ClO/sub 4/ systems. The sorption of Cd in the chloride system was in the range between 25 to 50 percent less than the ClO/sub 4/ systems for the same ionic strength. This was attributed to the presence of uncharged and negatively charged complexes of Cd with Cl ligands. This fact has some implications, especially in arid zone soils where high Cl concentrations in soil solutions are not unusual; there, Cd will behave mainly as a neutral species (CdCl/sub 2//sup 0/) and as an anion (CaCl/sub 3//sup -/ and CdCl/sub 4//sup 2 -/), rather than as a cation (Cd/sup 2 +/). The SO/sub 4/ systems showed a moderate decrease in the amount of Cd sorbed with respect to the ClO/sub 4/ systems for the same salt concentrations. This

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