Preparation of adsorbents from agro-industrial wastes and their application in the removal of Cd²⁺ and Pb²⁺ ions from a binary mixture: Evaluation of ionic competition

Abstract:

Adsorbents were prepared from agro-industrial wastes for the removal of Cd2+ and Pb2+ ions from a binary mixture. Of all the adsorbents prepared, that activated with H3PO4 obtained from peanut shell (AQps) had the highest adsorptive capacity as regards the removal of both metal ions. The operating conditions established were: pH 5.0; 2 gadsorbent Lsolution‐1 and 50 rpm. The kinetic showed rapid adsorption, and the equilibrium was reached in 3 min. Both pseudo-first-order and pseudo-second-order models represented the experimental data with R2 values > 0.91 and χ2< 0.0001 for all the concentrations studied. The extended Langmuir model fitted the experimental data, obtaining R2 = 0.90, with qmax of 0.7 ± 0.3 mmol g‐1 and KEL of 5.0 ± 3.6 L mmol‐1 for Cd2+ and qmax of 0.7 ± 0.1 mmol g‐1 and KEL 40.5 ± 14.9 L mmol‐1 for Pb2+. A decreasing trend in adsorptive capacity was also observed when the temperature was increased, indicating exothermic adsorption. During the evaluation of adsorbent recovery, when the volume of the eluent was five times smaller than that of the adsorbate, maximum desorption of 84.5 % for Cd2+ and 73.3 % for Pb2+ was obtained. In view of the above, AQps showed potential for simultaneous removal of Cd2+ and Pb2+ ions from aqueous media.

Año de publicación:

2022

Keywords:

• Extended Langmuir model
• Agro-industrial residue
• Binary mixture
• Desorption

Fuente:

google

scopus