Thermodynamic properties and adsorption behaviour of hydrogel nanocomposites for cadmium removal from mine effluents

• Published in: Journal of industrial and engineering chemistry (Seoul, Korea) Vol. 48; pp. 151 - 161
• Main Authors: Fosso-Kankeu, E., Mittal, Hemant, Waanders, F., Ray, Suprakas Sinha
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 25.04.2017; 한국공업화학회
• Subjects: Adsorption models; Cadmium ions; Hydrogel nanocomposite; Thermodynamic; 화학공학; Adsorption models; Cadmium ions; Hydrogel nanocomposite; Thermodynamic
• ISSN: 1226-086X; 1876-794X
• DOI: 10.1016/j.jiec.2016.12.033

[Display omitted] •The values of pzc confirmed the behaviour of the successfully synthesized adsorbents at low and high pH.•The isotherm models predicted the adsorption of cadmium on the outer and inner layer of the adsorbents.•The hybrid hydrogel composite exhibited higher affinity for Cd compared to GL–cl–PAAm.•Cd uptake by both adsorbents was found to be an endothermic and spontaneous process.•The two adsorbents showed good potential for the removal of metals from AMD. This research paper reports on the utilization of the hydrogel of gelatine (GL) and its hybrid nanocomposite with clinoptilolite for the adsorption of Cd2+ ions from an aqueous solution and multi-metal ions from mine effluents. The hydrogel was synthesized using the graft co-polymerization of acrylamide (AAm) onto GL and the hybrid hydrogel nanocomposite was prepared by incorporating clinoptilolite within the hydrogel matrix. The synthesized polymers were characterized using different characterization techniques such as FTIR, XRD, SEM and TGA. The adsorption behaviour of the synthesized adsorbents for the adsorption of Cd2+ was studied using different adsorption parameters such as pH, temperature and adsorbent dosage. Adsorption kinetics followed the pseudo-second-order rate equation, whereas, the adsorption isotherm followed both the Freundlich and Langmuir isotherm models. The thermodynamics studies revealed that the adsorption processes were spontaneous and endothermic in nature. Moreover, the synthesized adsorbents were also successfully utilized for the adsorption of different metal ions from the mine effluents.