Removal of 2,4-dichlorophenoxyacetic Acid by Calcined Zn–Al–Zr Layered Double Hydroxide

Authors

Allen Chaparadza, Marquette University
Jeanne Hossenlopp, Marquette UniversityFollow

Document Type

Article

Publication Date

11-1-2011

Source Publication

Journal of Colloid and Interface Science

Source ISSN

0021-9797

Abstract

The adsorption equilibrium, kinetics, and thermodynamics of removal of 2,4-dichlorophenoxy-acetic acid (2,4-D) from aqueous solutions by a calcined Zn–Al layered double hydroxide incorporated with Zr⁴⁺ were studied with respect to time, temperature, pH, and initial 2,4-D concentration. Zr⁴⁺ incorporation into the LDH was used to enhance 2,4-D uptake by creating higher positive charges and surface/layer modification of the adsorbent. The LDH was capable of removing up to 98% of 2,4-D from 5 to 400 ppm aqueous at adsorbent dosages of 500 and 5000 mg L⁻¹. The adsorption was described by a Langmuir-type isotherm. The percentage 2,4-D removed was directly proportional to the adsorbent dosage and was optimized with 8% Zr⁴⁺ ion content, relative to the total metals (Zr⁴⁺ + Al³⁺ + Zn²⁺). Selected mass transfer and kinetic models were applied to the experimental data to examine uptake mechanism. The boundary layer and intra-particle diffusion played important roles in the adsorption mechanisms of 2,4-D, and the kinetics followed a pseudo-second order kinetic model with an enthalpy, ΔH_ads of −27.7 ± 0.9 kJ mol⁻¹. Regeneration studies showed a 6% reduction in 2,4-D uptake capacity over six adsorption–desorption cycles when exposed to an analyte concentration of 100 ppm.

Comments

Accepted version. Journal of Colloid and Interface Science, Vol. 363, No 1 (November 2011): 92-97. DOI. © 2011 Elsevier. Used with permission.

Recommended Citation

Chaparadza, Allen and Hossenlopp, Jeanne, "Removal of 2,4-dichlorophenoxyacetic Acid by Calcined Zn–Al–Zr Layered Double Hydroxide" (2011). Chemistry Faculty Research and Publications. 82.
https://epublications.marquette.edu/chem_fac/82