INTERNATIONAL SCIENTIFIC RESEARCH AND INNOVATION CONGRESS -II
USE OF MECHANICALLY ACTIVATED SEASHELL POWDERS AS ADSORBENTS FOR THE REMOVAL OF METHYL VIOLET 6B DYE
In this study, mechanically activated seashells were used for the first time for the bioadsorption of methyl violet 6B dyestuff from aqueous solutions. The mechanical activation of the shells was carried out in a planetary ball mill at 600 rpm for 1 hour. The activated seashells (ASS) were characterised by FT-IR. For bioadsorption optimisation, initial dye concentration (10-50 mg/L), adsorbent amount (0.1-0.5 g/30 mL), temperature (25°C- 60°C), adsorption contact time (5-60 min) and pH 2-10 conditions were studied. In the studies, the maximum percentage yield of 92,50% was obtained in 30 minutes from 50 mg/L methyl violet solution using 0.2 g ASS at pH 6. Kinetic, thermodynamic and isotherm models were studied to determine the mechanism of bioadsorption. Equilibrium bioadsorption data were applied to Langmuir, Freundlich and Temkin isotherm models and the most appropriate Freundlich isotherm was found. Kinetic studies were carried out using pseudo-first-order and pseudo-second-order kinetic models, and it was determined that the pseudo-second-order kinetic model was the most suitable model. Thermodynamic parameters of the bioadsorption of ASS were calculated. According to the results, Gibbs free energy (ΔG°) value was found to be positive, while enthalpy (ΔH°) and entropy (ΔS°) values were found to be negative. The positive ΔG° value indicated that the adsorption process was not spontaneous. The negative ΔH° value indicates that it is an exothermic reaction. These findings demonstrated that activated seashell is an affordable and alternative method of removing Methyl Violet 6B dye from aqueous solutions.
