<p>This study investigates the synthesis and application of a novel mesoporous silica-based nanocomposite, functionalized with Ni₂O₃@Dy₂O₃, for the efficient removal of methylene blue (MB) dye from aqueous solutions. The nanocomposite was synthesized using hydrothermal method and characterized by FT-IR, XRD, BET, FE-SEM, and EDS analyses, confirming its successful formation with a uniform spherical morphology. The adsorption performance of the nanocomposite for methylene blue removal was evaluated under various operational conditions To optimize the adsorption process, various parameters such as pH, adsorbent dosage, contact time, and temperature were systematically investigated. The results revealed that the optimal conditions for MB removal were pH 7, an adsorbent dosage of 0.01 g, a contact time of 15 min, and a temperature of 25 °C. Under these conditions, the nanocomposite achieved a maximum removal efficiency of 99.48%. Kinetic studies indicated that the adsorption process followed pseudo-second-order kinetics, suggesting chemisorption as the rate-limiting step. The adsorption isotherm data were best fitted by the Langmuir model, indicating monolayer adsorption on a homogeneous surface. Thermodynamic studies revealed that the adsorption process was endothermic and spontaneous. The high removal efficiency and reusability of the synthesized nanocomposite make it a promising candidate for the effective removal of organic pollutants from wastewater, contributing to environmental sustainability.</p>