Equilibrium Constants between both Freshly Prepared and Aged H Montmorillonites and Chloride Salt Solutions

Freshly prepared and aged H montmorillonites were equilibrated with NaCl, KCl, MgCl 2 , and CaCl 2 solutions of low concentrations. With freshly prepared H montmorillonites equilibrium constants were obtained. With aged H montmorillonites equilibrium constants were not obtained because the 1 N KCl extracting technique did not yield the correct amount of adsorbed H + . To overcome this, a new method for determining adsorbed H + was used. However, the measured equilibrium constants were either smaller or contradictory to those obtained with freshly prepared H montmorillonites because it was not possible to assess the exact amount of adsorbed H + in the presence of hydroxyaluminum compounds. Thus, only equilibrium constants obtained with freshly prepared H montmorillonites were considered to be valid.