Synthesis, characterization and examination of sorption properties of menengic-based biosorbents

Textile dyes are one of the pollutants found in wastewater, which negatively affect human and environmental health. Removal of these chemicals from wastewater is important for that life of the living beings. After coating powdered material consisting of the inner shell of menengic with chitosan, two dyestuffs, indigo carmine and sulfur black, were studied. In this study, the powder of the inner peel of the menengic fruit was modified with chitosan and turned into microcapsules and used for the removal of indigo carmine and sulfur black from water. During the adsorption experiments, the effects of parameters such as substance amount, time, concentration and temperature were investigated. It was observed that the adsorption process reached equilibrium for indigo carmine at the amount of 0.04 g substance. It was observed that the adsorption process reached equilibrium for indigo carmine in 120 minute. At the same time, the pH value of indigo carmine solution was kept constant and unchanged in other experiments. It was observed that the adsorption process reached equilibrium at 0.04 g of substance for sulfur black. It was observed that the adsorption process reached equilibrium at 60 minute for sulfur black. At the same time, the pH value of the sulfur black solution was kept constant at 2 in other experiments and was not changed. In the last stage of the studies, Langmuir and Freundlich adsorption models were used to define the adsorption equilibrium mathematically and the model constants were calculated. As a result, it was seen that the experimental data conformed to the Langmuir isotherm model for both the indigo carmin solution and the sulfur black solution. In addition, kinetic constants of each model were found by investigating the compatibility of kinetic data with first-order and second-order kinetic models. Accordingly, it was seen from the constants that both indigo carmine solution and the sulfur black solution were more suitable for the second order kinetic model. Finally, the adsorption thermodynamic constants ∆H, ∆S, ∆G for each system were determined using thermodynamic equations.