Adsorption Of Mercury From Aqueous Solution Using Gum Acacia-silica Composite: Kinetics, Isotherms And Thermodynamics Studies

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

DOI: 10.5185/amlett.2016.6189

Publication Date (Web): Jul 01, 2016

Copyright © IAAM-VBRI Press

E-mail: somitsingh@gmail.com

Abstract

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.

Keywords

Gum acacia, nanocomposite, mercury adsorption, tetraethyl orthosilicate (TEOS), sol-gel.