Anion-Exchange Reactions of Layered Double Hydroxides: Interplay between Coulombic and H-Bonding Interactions

2009-07-01T00:00:00Z (GMT) by S. V. Prasanna P. Vishnu Kamath
The NO3- and Cl-containing layered double hydroxides (LDHs) of Mg with Al interact weakly with anions in solution under equilibrated conditions and yield a type V isotherm. The uptake of anions under nonequilibrated conditions varies monotonically with the layer charge when the outgoing anion is NO3, whereas it goes through a maximum when the outgoing anion is Cl. These observations suggest that Coulombic interactions play a dominant role in Cl-LDHs, whereas weak interactions governing the mode of intercalation of NO3 ions influence the exchange reactions of NO3-LDHs. These studies have significant implications for the remediation of insidious anions by LDHs.