Boron Adsorption by Montmorillonite as Affected by Particle Size

The effect of clay particle size on B adsorption by the Na and Ca forms of montmorillonite was determined at two pH levels. Boron adsorption by the smaller clay particles of both Na and Ca forms was much greater than by the larger clay particles at both pH levels. The increase in B adsorption in the smaller clay particle systems was related to the increase in the edges' surface area of the clay platelets. Data from batch experiments were compared with results computed according to fitted adsorption coefficients (maximum B adsorption and affinity coefficients which related to the binding energy). The agreement between calculated values and experimental results indicates that the adsorption model can be used to predict B adsorption by Na‐ and Ca‐montmorillonite at various particle sizes.