Facile synthesis of ZnAl-EDTA layered double hydroxide/poly(vinyl alcohol) nanocomposites as an efficient adsorbent of Cd(II) ions from the aqueous solution

Abstract

In this study, ethylenediaminetetraacetic acid-layered double hydroxides/ poly(vinyl alcohol) nanocomposites (EDTA-LDH/PVA NCs) were synthesized by the solution casting method through ultrasonic irradiation. ZnAl-EDTA layered double hydroxide prepared by employing the co-precipitation method, and 2, 4 and 8 wt of this nanofiller was added to the PVA matrix in the aqueous medium. The chemical structure, morphology, and thermal properties of the EDTA-LDH/PVA NCs were investigated by several techniques. The resulting EDTA-LDH/PVA NCs were investigated for Cd(II) ion removal by considering such optimized parameters as pH, contact time and ions concentration. Finally, the adsorption isotherms models, such as Freundlich and Langmuir, and the adsorption kinetics of EDTA-LDH/PVA NCs were investigated. The Cd(II) ion removal was increased after adding EDTA-LDH to the PVA matrix. The pseudo second-order model could be a suitable model to interpret the adsorption mechanism of Cd(II) ions. The Langmuir isotherm was found to be the best model in exhibiting the adsorption of Cd (II) onto EDTA-LDH/PVA NCs adsorbents.