Thermodynamic Modeling, Desorption Kinetics, and Multilayer Adsorption of Crystal Violet Dye onto Modified Illite Clay

International Journal of Chemistry | Vol. 5, No. 7, July 2014 | pp. 49–56

DOI: 10.46882/2014/IJC/000070

Article Type: Original Research Paper

Title: Thermodynamic Modeling, Desorption Kinetics, and Multilayer Adsorption of Crystal Violet Dye onto Modified Illite Clay

Names of Authors: A. D. Yusuf¹, M. T. Al-Hajri²*

Authors’ Affiliations:
¹Department of Industrial Chemistry, Federal University of Technology, Yola, Nigeria.
²Department of Chemistry, Qatar University, Doha, Qatar.

Abstract: The release of highly stable cationic triphenylmethane dyes like Crystal Violet from textile finishing plants causes significant environmental and toxicity hazards in surface aquatic resources. This study examines the adsorptive uptake performance of a surfactant-modified illite clay (SMI) prepared via chemical functionalization with dodecyltrimethylammonium bromide (DTMA-Br). The structural parameters of raw and modified clays were characterized using X-ray diffraction (XRD) and FT-IR spectroscopy. Adsorption operations were conducted via batch runs, monitoring changes in contact time, solution pH, initial dye loading concentrations, and system temperatures. The equilibrium datasets fit closely with the Freundlich isotherm model, demonstrating successful multilayer dye attachment onto the hydrophobic surfactant bilayers. Kinetic parameters matched the intra-particle diffusion expressions alongside a pseudo-second-order mechanism, showing that chemisorption reactions controlled the mass transfer rates. Thermodynamic constants showed that the adsorption process was endothermic (delta H° = 24.5 kJ/mol) and caused an increase in system randomness at the solid-solution interface (delta S° = 78.4 J/mol K). Negative values of Gibbs free energy (delta G°) spanning from -2.1 to -5.4 kJ/mol across the 298 to 328 K range confirmed process spontaneity, positioning SMI as an affordable material for industrial dye wastewater treatment.

Keywords: Illite clay; Surfactant modification; Crystal violet; Adsorption isotherm; Chemisorption; Thermodynamic parameters

Manuscript Timeline: Received: July 20, 2013; Revised: August 28, 2013; Accepted: September 15, 2013; Published: July 08, 2014.

Citation: Yusuf, A. D., & Al-Hajri., M. T. (2014). Thermodynamic Modeling, Desorption Kinetics, and Multilayer Adsorption of Crystal Violet Dye onto Modified Illite Clay. International Journal of Chemistry, 5(7), 49–56.

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