The rapid growth of industrial sectors such as textiles, pharmaceuticals, and leather tanning has significantly increased the discharge of synthetic dyes into aquatic environments. Among these pollutants, Rhodamine B (RhB) is of particular concern because it is toxic, highly stable, and resistant to conventional biological, chemical, and physical treatments. Incomplete degradation and the generation of secondary contaminants are major drawbacks of traditional methods, which highlights the urgent need for sustainable and more efficient alternatives. Nanomaterials have recently gained wide attention in wastewater treatment due to their high surface area, tuneable surface chemistry, and strong adsorption capacity. In this context, green synthesis of nanoparticles offers additional advantages by avoiding hazardous chemicals and employing plant-derived bioactive compounds as natural reducing and stabilizing agents [1-3]. In the present study, Cu/TiO₂ nanoparticles were synthesized via a green route and evaluated as adsorbents for RhB removal from aqueous solution. The NPs were characterized using XRD, FESEM, BET and EDAX analysis, revealing uniform dispersion, an average particle size of approximately 20.5 nm, and a high surface area of 92 m²/g. Additionally, 3D surface analysis indicated a moderate level of surface roughness (RMS~7.5 nm), which supports the presence of sufficient accessible sites for interaction with dye molecules. Batch adsorption experiments were carried out at initial RhB concentrations ranging from 1 to 10 mg/L with a contact time of 150 min. Equilibrium data were analyzed using three classical isotherm models, Langmuir, Freundlich, and Temkin, to assess adsorption behaviour through chemometric modelling and statistical fitting. The results showed that the Freundlich isotherm exhibited the strongest correlation with the experimental data (R² = 0.9995), indicating heterogeneous surface adsorption and multilayer coverage. The Langmuir model also provided a good fit (R² = 0.9946), suggesting partial monolayer formation, while the Temkin model showed weaker applicability (R² = 0.9273). The maximum adsorption capacity (qmax) was 19.12 mg/g, demonstrating the high uptake potential of the synthesized adsorbent. Furthermore, analysis of the Freundlich constant revealed that (n–1) was 0.7713, which lies within the range of 0
