The effects of three electrolyte anions, ionic strength and pH on the adsorption of sulfate by two variablecharge soils, with different surface charge properties were studied. Under the conditions of the same pHand io...The effects of three electrolyte anions, ionic strength and pH on the adsorption of sulfate by two variablecharge soils, with different surface charge properties were studied. Under the conditions of the same pHand ionic strength the effect of electrolyte anions on the adsorption of sulfate was in the order of , indicating the difference of the nature among these three anions. For Ferralsol in the sameconcentration of chloride and perchloride solutions, the two sulfate adsorption-pH curves could intersectat certain pH value. When pH was higher than the intersecting point, more sulfate was adsorbed in theperchloride solution, while when it was lower than the intersecting point, more sulfate was adsorbed in thechloride solution. In different concentrations of electrolyte solution, the curves of the amount of oxy-acidanion adsorbed, which changed with pH, could intersect at a certain pH, which is termed point of zero salteffect （PZSE） on adsorption. The nature of electrolyte anions influenced obviously the appearance of PZSEfor sulfate adsorption. For ferraisol the curves of adsorption converged to about pH 7 in NaCl solution seemedto intersect in NaNO<sub>3</sub> solution and to have a typical PZSE for sulfate adsorption in NaClO<sub>4</sub> solution. ForAcrisol the three curves of adsorption were nearly parallel in NaCl and NaNO<sub>3</sub> solutions and converged topH 6.5 in NaClO<sub>4</sub> solution.展开更多
文摘The effects of three electrolyte anions, ionic strength and pH on the adsorption of sulfate by two variablecharge soils, with different surface charge properties were studied. Under the conditions of the same pHand ionic strength the effect of electrolyte anions on the adsorption of sulfate was in the order of , indicating the difference of the nature among these three anions. For Ferralsol in the sameconcentration of chloride and perchloride solutions, the two sulfate adsorption-pH curves could intersectat certain pH value. When pH was higher than the intersecting point, more sulfate was adsorbed in theperchloride solution, while when it was lower than the intersecting point, more sulfate was adsorbed in thechloride solution. In different concentrations of electrolyte solution, the curves of the amount of oxy-acidanion adsorbed, which changed with pH, could intersect at a certain pH, which is termed point of zero salteffect （PZSE） on adsorption. The nature of electrolyte anions influenced obviously the appearance of PZSEfor sulfate adsorption. For ferraisol the curves of adsorption converged to about pH 7 in NaCl solution seemedto intersect in NaNO<sub>3</sub> solution and to have a typical PZSE for sulfate adsorption in NaClO<sub>4</sub> solution. ForAcrisol the three curves of adsorption were nearly parallel in NaCl and NaNO<sub>3</sub> solutions and converged topH 6.5 in NaClO<sub>4</sub> solution.
