A kinetic analysis of intercalation of organic sulfate anions into layered double hydroxide using quartz crystal microbalance with layered double hydroxide-immobilized electrode

To investigate a dynamic intercalation behavior of organic anions into layered double hydroxide (LDH) interlayer by ion-exchange, a quartz crystal microbalance (QCM) with the Mg-Al LDH thin film immobilized gold disc (LDH/QC) electrode has been used. A stable minute LDH film was prepared by using translucent aqueous sol of LDH containing OH- ions and magnesium acetate molecule in the interlayer and immobilized on the gold disc after pretreatment of the surface of the supporting silica electrode with hydrophobic agent. In the kinetic analysis, alkyl sulfates having n-alkyl chain (CnH2n+1, n = 5-12; abbreviated as CnS) were used as guest anions. As the results, the time-dependence on CnS intercalation by ion-exchange with guest OH- ions and magnesium acetate molecules was measured in the cases of CnS (n > 7), and the data of C11S and C12S intercalation were successively analyzed using the rate equation based on the reversible pseud first-order reaction. Finally, the instrumental analyses of the LDH films before and after the intercalation of C12S revealed that the organic anions could be intercalated into the LDH interlayer of the LDH/QC electrode in each aqueous solutions. (C) 2021 The Ceramic Society of Japan. All rights reserved.