Deriving Boron Adsorption Isotherms from Soil Column Displacement Experiments

This study was conducted to elucidate the applicability of the column technique to obtain B adsorption isotherms. A column technique based on miscible displacement was used to investigate B equilibrium adsorption and B transport in soil at various pHs and B concentrations. Boron adsorption by soil at equilibrium was described by the Langmuir equation with the pH‐dependent apparent adsorption coefficient. This equation, combined with one‐dimensional convection–dispersion equation (CDE), was used to simulate B transport in soil columns. The results indicated that adsorption equilibrium was reached during the B transport in the homogeneously packed soil columns. The adsorption isotherms that were obtained from the column breakthrough curves (BTCs) and the batch experiments were identical at any given pH. This indicates that under equilibrium conditions, the column technique can be used for calculating B adsorption isotherm parameters for any given pH.