The removal of Cr(VI) from aqueous solution by a Mg-Al layered double hydroxide (Mg-Al LDH) doped with Fe2+ increased with time and temperature. Cr(VI) removal could not be described by first-order reaction kinetics, but it was well represented as a pseudo second-order reaction. The apparent rate constants at 10, 30, and 60°C were 0.9×10-3, 1.2×10-3, and 2.2×10-3gmmol-1min-1, respectively, and the apparent activation energy was 14.5kJmol-1. This value confirms that the rate-determining step for Cr(VI) removal is chemical adsorption involving the anion exchange of Cr2O72- with intercalated Cl- and the adsorption of Cr2O72- on the surface of the produced FeO(OH).
- Layered double hydroxide
ASJC Scopus subject areas
- Safety, Risk, Reliability and Quality
- Waste Management and Disposal
- Process Chemistry and Technology