Removal Of Chloride Ion From Aqueous Solution By Znal-no_3 Layered Double Hydroxides As Anion-exchanger

摘要

The layered double hydroxides (LDHs) containing nitrate as the interlayer anion has a high anion-exchange capacity in the presence of appropriate anions. In the light of this, ZnAl-NC_3 LDHs have been employed to remove chloride ion from aqueous solution in a batch mode. The influences of conditions for chloride ion uptake, including dosage of LDHs, pH of aqueous solution, and temperature on anion-exchange have been investigated, respectively. The thermodynamic parameters including Gibbs free energy (△G~0), standard enthalpy change (△H~0), and standard entropy change (△S~0) for the process were calculated using the Langmuir constants. It was found from kinetics test that the pseudo-second order kinetics model could be used to well describe the uptake process. An E_a value of 10.27 kJ/mol provides evidence the anion-exchange process. The explanation of anion-exchange phenomenon has also been supported by X-ray diffraction and FT-IR spectra.