Polyacrylic acid-based and chitosan-based hydrogels for adsorption of cadmium: Equilibrium isotherm, kinetic and thermodynamic studies
By P. B. Vilela, C. Matias, Amanda Dalalibera, V. A. Becegato, Alexandre T. Paulino. Journal of Environmental Chemical Engineering, 2019
162 citations recorded by the source corpus.
Abstract The aim of present study was to determine the efficacy of polyacrylic acid-based and chitosan-based hydrogels (synthesized via chemical crosslinking) for the adsorption and removal of cadmium contained in aqueous solutions. Reactive functional groups involved in the adsorption of cadmium were confirmed by Fourier-transform infrared spectroscopy and cadmium adsorbed to the hydrogel surface was confirmed by scanning electron microscopy coupled to energy-dispersive X-ray spectroscopy. The cadmium adsorption mechanism was evaluated using non-linear Langmuir, Freundlich, Redlich-Peterson and Sips isotherms, with the best fits found using the non-linear Sips and Redlich-Peterson isotherms for adsorption to polyacrylic acid-based and chitosan-based hydrogels, respectively. Maximum cadmium adsorption capacities of the polyacrylic acid-based and chitosan-based hydrogels were respectively 197.92 and 234.84 mg of metal per g of dried hydrogel at pH 6.0 and 343.0 ± 1.0 K. The best kinetic fit for adsorption to the chitosan-based hydrogel was found with the pseudo-second order kinetic model, whereas the best kinetic fit for adsorption to the polyacrylic acid-based hydrogel was found with the pseudo-first order kinetic model. The thermodynamic results indicated that the adsorption of cadmium to both hydrogels is a favorable, spontaneous process. The desorption studies suggested the formation of reversible chemical bonds between cadmium and active groups in the hydrogel network.
View Paper: https://www.semanticscholar.org/paper/d2610eceb3e239a0f1fe677a207ca3f69574b7f4
How researchers see this paper
The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.
Citations in the corpus
- A Critical Overview of Adsorption Models Linearization: Methodological and Statistical Inconsistencies (2021, background): “If ΔH° > 0, adsorption is endothermic, while it is exothermic when ΔH° < 0.([99]) Many of the reported adsorbate-adsorbent systems are exothermic, but one feasible explanation for the endothermic behavior is that when ions are about to be adsorbed, they lose part of their hydration sheath.”