Adsorption of mercury from aqueous solution using gum acacia-silica composite: kinetics, isotherms a Adsorption of mercury from aqueous solution using gum acacia-silica composite: kinetics, isotherms a
1Department of Chemistry, School of Physical Sciences, College of Natural and Mathematical Sciences, The University of Dodoma, PO Box 259, Tanzania
2Department of Chemistry, University of Allahabad, Allahabad 211002, India
Adv. Mater. Lett., 2016, 7 (8), pp 673-678
Publication Date (Web): Jul 01, 2016
Copyright © IAAM-VBRI Press
In the present investigation, the remediation of mercury by using the gum acacia-silica composite as an adsorbent has been studied. Experiments revealed optimum parameters which were found to be pH 6, contact time 2 hours, Hg(II) concentration of 100 ppm, reflux temperature 30 0C and adsorbent dosage of 50 mg. The experimental data was subjected to modeling using the Langmuir and Freundlich isotherms. It was found that the data very well fitted to the Freundlich model. The pseudo second order kinetics confirms chemisorption with rate constant 3.1 × 10-4 gmg-1min-1. The calculated thermodynamic parameters (?G0, ?S0, ?H0) revealed the exothermic and spontaneous nature of adsorption process at the solid–solution interface. The adsorbent could be recycled for six successive cycles with 31.5% loss in its efficiency. The adsorbent is found to be highly effective and economical for mercury remediation from water.
Gum acacia, nanocomposite, mercury adsorption, tetraethyl orthosilicate (TEOS), sol-gel.