Bitlis/Mutki kilinin üzerine boyar madde adsorpsiyonunun araştırılması

Today, wastewater contaminated with dyes, particularly as a result of industrial activities in the textile, paper, paint, food, and pharmaceutical industries, poses a significant environmental pollution problem. In this study, the removal of two cationic dyes, Methylene Blue (MB) and Malachite Green (MG), from aqueous media by adsorption was investigated using natural clay from the Mutki district of Bitlis province. After the clay sample used in the study was obtained from the field, it underwent physical pretreatment; it was washed with pure water, dried, and homogenized. The prepared natural clay sample was used as an adsorbent. Within the scope of the experimental studies, various parameters affecting the adsorption process were examined. These parameters included the pH value of the solution, temperature, initial dye concentration, adsorbent amount, and contact time. To determine the adsorption efficiency, isotherm and kinetic studies were conducted using MM and MY solutions at different concentrations. The obtained data were applied to Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich (D-R) isotherm models; the Freundlich isotherm was determined to be the most suitable model for both dyes. This indicates that adsorption occurs in multiple layers on heterogeneous surfaces and that the surface contains different energy regions. Kinetic analyses revealed that the adsorption process showed high compliance with the pseudo-second-order (PSO) kinetic model. This finding indicates that the adsorption mechanism is based on physical interactions with active regions on the surface rather than chemical interactions. Thermodynamic investigations revealed that the Gibbs free energy change (ΔG°) was calculated as negative at all temperatures, indicating that adsorption occurs spontaneously. Positive enthalpy (ΔH°) values indicate that the process is endothermic, while positive entropy (ΔS°) values indicate an increase in disorder in the system and compatibility between the adsorbent and the adsorbed species. The results show that natural clay obtained from the Bitlis/Mutki region can be used with high efficiency in the removal of cationic dyes in their natural state. In this context, it has been concluded that the clay mineral in question can be considered a low-cost, environmentally friendly, and sustainable adsorbent alternative for the treatment of industrial wastewater.