Kinetic and Thermodynamic Studies of the Adsorption of Methylene Blue on Processed and Unprocessed Cotton Fibre

Abstract

The use of cotton fibre (processed and unprocessed) for the adsorption of methylene blue and indigo solution at different contact time with temperature, pH and temperatures were investigated. The adsorbent showed good potential for adsorption of methylene blue at 298 K and 308 K with maximum uptake of 4.00 mg/g for processed and unprocessed cotton respectively. Experimental data were analyzed by using two adsorption isotherms (Langmuir and Freundlich). Langmuir model shows best fit compared to Freundlich model. Pseudo – second order best describe their adsorption kinetic on the experimental data. Thermodynamic parameters such as ΔH°, ΔG° and ΔS° proved that adsorption mechanism of methylene blue is spontaneous and endothermic in the ranges of temperature 288 – 308 K for processed cotton fibre while it was also spontaneous and exothermic in the range of temperature 288 – 308 K for unprocessed cotton fibre. This results of this study showed that cotton fibre (processed and unprocessed) can be used as adsorbent for the adsorption of methylene blue.