The removal of chloride from solutions with various cations using magnesium-aluminum oxide

We investigated the removal of chloride from various solutions (NaCl, HCl, MgCl2, AlCl3, CaCl2, and NH4Cl) at 60 degrees C for 3h using magnesium-aluminum oxide, Mg0.80Al0.20O1.10, prepared by the thermal decomposition of a hydrotalcite-like compound, Mg0.80Al0.20(OH)(2)(CO3)(0.10)center dot 0.78H(2)O. The degree of Cl- removal from solution increased with the amount of Mg0.80Al0.20O1.10 used. When Mg0.80Al0.20O1.10 was added to 0.5 M Cl- solutions of HCl, MgCl2, AlCl3, and NH4Cl in a Mg0.80Al0.20O1.10/Cl- molar ratio of 8.75, the degree of Cl- removal exceeded 95%. The degree of Cl- removal from NaCl and CaCl2 solutions was slightly lower, approximately 80 and 90%, respectively. These results reveal that both the amount of Mg0.80Al0.20O1.10 added to chloride solution and the nature of the cations in the solution affect the efficiency of Cl- removal from solution. (C) 2004 Elsevier B.V. All rights reserved.