Stability of an organoclay complex: effects of high concentrations of sodium chloride

This study tests the stability of an organoclay complex (clay–BTMA0.5) and its adsorption capacity for a non-ionic organic chemical under various sodium chloride (NaCl) concentrations. Adsorption of benzyltrimethylammonium (BTMA) to montmorillonite and its desorption from the organoclay complex under various NaCl concentrations were measured. Results showed a decrease in the amount of BTMA adsorbed as the NaCl concentration increased from 0 to 100 g/l. Release of BTMA from the organoclay complex (clay–BTMA0.5) increased as NaCl concentration reached 100 g/l; however, desorption of BTMA was always less than 10% of the adsorbed amount. Solutions of BTMA increased the solubility of phenanthrene in water. Adsorption of phenanthrene by the clay–BTMA0.5 increased as NaCl concentration increased. Addition of NaCl to the system further increased the adsorbed amount of phenanthrene. These results indicate the stability of the organoclay complex (clay–BTMA0.5) under various NaCl concentrations and that its adsorption capacity towards phenanthrene was not significantly affected. Thus, the use of clay–BTMA0.5 may be useful in attenuating the concentration of organic pollutants as phenanthrene from distilled or saline water.