Journal of Emerging Trends in Engineering and Applied Sciences: Research Areas

Article Title: Equilibrium and Thermodynamic Studies for Adsorption of Methylene Blue Dye onto Raw Cassava Peel (RCP)
by Enenebeaku Conrad Kenechukwu, Okorocha J. Nnaemeka, Akalezi Chris Oudney, Odionye Uchechi Emmanuela, Oguzie Emeka Emmanuel

Abstract:
Colour removal from wastewater has been a matter of concern, both in the aesthetic sense and health point of view. Colour removal from textile effluents on a continuous industrial scale has been given much attention in the last few years, not only because of its potential toxicity, but also mainly due to its visibility problem. There have been various promising techniques for the removal of dyes from wastewater. However, the effectiveness of adsorption for dye removal from wastewater has made it an ideal alternative to other expensive treatment methods. The potential of using raw cassava peel (RCP) as adsorbent for the removal of methylene blue (MB) dye from aqueous solution was investigated. The adsorbent was characterized by Fourier transformer infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) techniques. The effect of experimental parameters such as pH, contact time, initial concentration of adsorbate and amount of adsorbent dosage was evaluated. The maximum adsorption capacity of RCP for MB was found to be 32.26mg/g at 343k and pH 8.0 and 90 mins contact time for 100mg/l initial MB dye concentration. Adsorption isotherms were developed and equilibrium data fitted well to Langmuir, Freundlich, and Temkin isotherm models. Kinetic studies showed the adsorption process followed pseudo second-order kinetic model. Adsorption mechanism was investigated with intra-particle diffusion model to get a better understanding of the adsorption process and it indicated that intra-particle diffusion is not the rate determining step. Thermodynamic quantities (?G0,?H0 and ?S0) were evaluated and the negative ?G values obtained indicate a spontaneous adsorption process, positive ?H value obtained indicate the endothermic nature of the adsorption process and positive ?S value obtained indicate increased randomness during the adsorption process. Based on the results obtained such as good uptake capacity, rapid kinetics, and its low cost, RCP appears to be a promising adsorbent material for the removal of MB dye stuff from aqueous media.

Keywords: adsorption, methylene blue; cassava peels; isotherms; kinetics

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