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Adsorption of a Cationic Dye from Aqueous Solutions by using Waste Glass Materials: Isotherm and Thermodynamic Studies

Zainab A. Hadi, A. M. Aljeboree and A. F. Alkaim

Waste glass materials (WG), from Pepsi Cola solid wastes (PCSW), may be used as a sorbent for textile dyes removal from industrial wastewaters such as methylene blue (MB). In order to obtain the adsorption mechanism, adso rption processes were studied with Fo urier transform infrared spectroscopy. The effect of various parameters like concentration, initial solution pH, particle size, mass dosage and temperature has been studied. Increasing the concentra tion of the adsorbent promoted an increase in the percentage of removal until saturation of the adsorbent. Also increase in pH of solution gives better adsorption. However, it is also observed that percen t saturation of adsorption d ecreases with increase in particle size of adsorbent. The experimental isotherm data were analyzed using Langmuir, Freundlich, and Temkin models. Within the studied range of dye concentrations, the adsorption equilibrium was found to follow the Langmuir isotherm model well, with R 2 > 0.99. The dimensionless factor, R L of the methylene blue, WG isotherm revealed that the adsorption process is favourable in nature. A full thermodynamic evaluation was carried out, calculating the para meters of enthalpy, fr ee energy, and entropy ( ∆ H , ∆ G , and ∆ S ). The thermodynamics of MB onto WG system indicates spontaneous and endothermic nature of the process. The efficiency of WG for the spontaneous and endothermic adsorption of MB dye is attributed to the copious availability of hydroxyl and other polar functi onal groups on the oxygen surface. The present adsorption studies of MB dye from aqueous solution revealed the potential of WG to be utilized as an alternative, inexpensive, and environmentally benign adsorbent for water purification.