A CHROMATOGRAPHIC APPROACH TO THE DETERMINATION FO SULFATE ADSORPTION AND EXCHANGE OF LESS-RETENTIVE SOILS

A chromatographic method was employed for studying sulfate adsorption and exchange on 12 less-retentive soils. Adsorption of sulfate by soils from dilute solutions showed good agreement with the Freundlich isotherm. The equilibrium coefficient (soil-SO/sub 4//solution-SO/sub 4/) is rather constant for each of these less-retentive soils. A nearly complete exchange of the adsorbed S35O/sub 4/ was found in most soils, and rate of exchange varied with soil type. In a few soils the amount of nonexchangeable (difficulty exchangeable) sulfate increased when the soils were equilibrated with a higher sulfate concentration. The data also indicated that in four soils there were two sites of sulfate adsorption or exchange, and in the other eight only one site. Adsorption at site a is in kinetic equilibrium with that at site b. (auth)