Chapter 9: Movement of Solutes in Soil: Principles of Adsorption/Exchange Chromatography

Abstract

The recognition of the problem of predicting the motion of dissolved components through soil stems from the time when fertilizers came into use in agriculture. The implications of solute displacement have been manifesting ever since it was noted that agricultural land may become spoiled following the regular application of water for irrigation purposes. Attempts toward a quantitative description of the motion of solutes through soil date from the period following the Second World War. In that period, the synthetic ion exchangers had made their entry into the chemical world and considerable attention was paid in the chemical engineering literature to models describing the performance of ion-exchange columns. Recognizing that, in practice, the relevant parameters that determine solute displacement in soil are often not known with accuracy. There is a need to single out the parameters whose values are likely to be of decisive importance. These should then be measured with accuracy. A more accurate prediction could be made by means of a computer-simulation procedure. Different aspects of the displacement process are discussed in this chapter. The chapter presents an analysis that allows determining the magnitude of the relevant parameters, even if only scant experimental information is available, and understanding the conditions under which this magnitude is likely to be of critical importance.