Adsorption isotherms, kinetics and mechanism for the adsorption of cationic and anionic dyes onto carbonaceous particles
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ORIGINAL PAPER
Adsorption isotherms, kinetics and mechanism for the adsorption of cationic and anionic dyes onto carbonaceous particles prepared from Juglans regia shell biomass S. Nethaji • A. Sivasamy • A. B. Mandal
Received: 4 November 2011 / Revised: 25 May 2012 / Accepted: 2 August 2012 / Published online: 16 November 2012 Ó CEERS, IAU 2012
Abstract In the present study, Juglans regia shells were used to prepare activated carbon by acid treatment method. J. regia shell-based activated carbon was used for the adsorption of two synthetic dyes namely, a basic dye malachite green and an acid dye amido black 10B. The prepared adsorbent was crushed and sieved to three different mesh sizes 100, 600 and 1,000 lm. The adsorbent was characterized by scanning electron microscopy, surface acidity and zero-point charge. Batch experiments were carried out by varying the parameters like initial aqueous phase pH, adsorbent dosage and initial dye concentration. The equilibrium data were tested with Langmuir, Freundlich, Redlich–Peterson and Sips isotherm at three different temperatures 293, 300 and 313 K and it was found that the Freundlich isotherm best fitted the adsorption of both the dyes. Kinetic data were tested with pseudo first-order model and pseudo second-order model. The mechanism for the adsorption of both the dyes onto the adsorbent was studied by fitting the kinetic data with intraparticle diffusion model and Boyd plot. External mass transfer was found to be the rate-determining step. Based on the ionic nature of the adsorbates, the extent of film diffusion and intraparticle diffusion varied; both being system specific. Thermodynamic parameters were also calculated. Finally, the process parameters of each adsorption system were compared to develop the understanding of the best suitable system.
Electronic supplementary material The online version of this article (doi:10.1007/s13762-012-0112-0) contains supplementary material, which is available to authorized users. S. Nethaji A. Sivasamy (&) A. B. Mandal Chemical Engineering Area, CSIR-Central Leather Research Institute (Council of Scientific and Industrial Research), Adyar, Chennai 600020, India e-mail: [email protected]
Keywords Adsorption Malachite green Amido black Intraparticle diffusion Boyd plot
Introduction Underground water is the major source of drinking water. This underground water is being polluted by the wastewater containing a large number of contaminants like acids, bases, toxic organics, inorganics, heavy metals (Repo et al. 2010), dissolved solids and colors disposed by leather and textile industries. Out of all such contaminants, color is the most visible pollutant and the presence of very minute quantity makes it undesirable for use. Some of the dyes are toxic, stable and non-biodegradable (Gupta et al. 2004). Thus, the removal of color from dye-bearing effluents becomes a major challenge due to the difficulty in treating such wastewaters by conventional treatment methods such as chemical and biological oxidation meth
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