Removal of Aquatic Chromate Ion Involving Rehydration Reaction of Calcined Layered Double Hydroxide (Mg-Al-CO3)
- 1 February 1997
- journal article
- research article
- Published by Taylor & Francis in Environmental Technology
- Vol. 18 (2) , 231-236
- https://doi.org/10.1080/09593331808616532
Abstract
A synthetic layered double hydroxide (LDH: Mg-Al-CO3) was heated to 560 °C for 3 h in air, and the resulting calcined LDH (1.00 g dm−3) was used in the sorption study of aquatic CrO4 2− (concentration range: 1.0 × 10−3 − 5.0 × 10−3 mol dm−3) under CO2 free atmosphere. Reconstructed LDH containing intercalated CrO4 2− between interlayers was formed and this was confirmed by X-ray powder diffraction (XRD), 27Al MAS NMR, FT-IR and UV/VIS spectroscopies. The sorption of CrO4 2− by LDH resulted in increased hydroxide concentration, suggesting that ion-exchange based mechanism is involved: LDH + CrO4 2− = LDH(CrO4)+ 2OH−. The equilibrium constant (K), for sorption of CrO4 2−, based on ion-exchange with two OH− per unit LDH (composition: Mg6Al2(OH)18), of 3.1 ± 0.4 mol dm−3 was evaluated by a non-linear least squares fit procedure.Keywords
This publication has 0 references indexed in Scilit: