Methylene blue is the most commonly used cationic dye in textile, paper and printing industries. Exposure to methylene blue can cause severe effects on human and aquatic life, therefore, removal of such dye from process effluent is of significant concern. Among several existing techniques, adsorption onto activated carbon has been found to be superior for removal of dyes from aqueous solution because of its great ability for efficient adsorption. Production of activated carbons from bio-waste materials offers an alternative to the non-renewable and expensive source based commercially available activated carbons. The objective of this study is to examine the methylene blue adsorption onto activated carbon produced from jamun (Syzygium cumini) seed by chemical activation with KOH, followed by pyrolysis at 900 °C. As-prepared activated carbon was found to have a high surface area (747.5 m2 g-1) and large pore volume (up to 0.41 cm3 g-1). Methylene blue adsorption studies were carried out under varying conditions of agitation time, amount of carbon dosage, initial dye concentration, pH, and temperature to investigate the adsorption potential of prepared adsorbent. Maximum removal efficiency was measured as 97.77%. Adsorption capacity was found to be increased with increasing temperature, while adsorption process was unaffected by the solution pH. Experimental data were analyzed using linear and non-linear equations of four isotherm models (Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich) and three kinetic models (pseudo-first order, pseudo-second order, and intraparticle diffusion). The goodness-of-fit of linear and non-linear isotherm models was compared to find out the best fit of adsorption process. The obtained analysis results show that the Temkin isotherm and pseudo-second order kinetic model correlate the experimental data well. The calculated thermodynamic parameters such as ΔG°, ΔH°, and ΔS° revealed that the adsorption process was spontaneous and endothermic under examined conditions.

Adsorption of methylene blue onto activated carbon prepared from KOH-treated jamun (Syzygium cumini) seed: Equilibrium, kinetic and thermodynamic studies

255th National Meeting (2018)

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