New model describes nickel and phosphate sorption

Reactions between ions and the soil surface can be affected by other ions in the environment. For example, studies have shown that the presence of inorganic anions increases the sorption of several transition metal cations. Modeling the behavior of chemicals in soil is important for evaluating their environmental risk. However, many common approaches cannot account for interactions among multiple ions in a system.

In a new Soil Science Society of America Journal article, researchers investigated how phosphate affects the sorption of nickel (II) ions by soil. The authors found that phosphate increased both the total amount and rate of Ni(II) sorption while Ni(II) increased the amount of phosphate sorption but had no effect on its sorption rate. The authors then developed a model describing the sorption of Ni(II) in the presence of a range of phosphate concentrations, and vice versa, with a single set of parameters.

Phosphate fertilizers often contain heavy metal impurities, and mineral phosphate is commonly applied to remediate soils contaminated by heavy metals. Therefore, the model presented in this article could apply to a variety of settings and be more effective than traditional empirical approaches.