Abstarct: In this study, the simultaneous removal of methyl violet and methylene blue, as two cationic dyes, was performed using a hydroxyapatite-MIL-101(Al) composite. Hydroxyapatite was synthesized via the chemical co-precipitation method, while the mextal-organic frxamework and hydroxyapatite-MIL-101(Al) composite were both synthesized through the hydrothermal method. The resulting composite was characterized using techniques such as Field Emission Scanning Electron Microscopy (FESEM), Energy-dispersive X-ray spectroscopy (EDX), and Fourier-Transform Infrared Spectroscopy (FT-IR). The effects of parameters including solution pH, contact time, initial concentration of the dual-dye solution, adsorbent dosage, and temperature on the removal efficiency and adsorption capacity were studied. For the single-component system, Langmuir, Freundlich, Dubinin-Radushkevich, and Temkin isotherms were evaluated. In the single-component system, methyl violet (R² = 0.9861) and methylene blue (R² = 0.9967) showed the best fit with the Temkin and Langmuir isotherms, respectively. The maximum adsorption capacity (qmax) baxsed on the Langmuir isotherm at 20°C and pH = 5.9 in 100 mL of single-component solution was determined to be 161.3 mg/g for methyl violet and 166.7 mg/g for methylene blue. In the binary system under these conditions, the adsorption capacities were 66.1 mg/g for methyl violet and 116.3 mg/g for methylene blue. For the binary system, the extended Freundlich equation (Sheindorf) was used, yielding competition coefficients (aij and aji) of 1.45 and 0.06 for methyl violet and methylene blue, respectively, indicating greater interference of methylene blue on methyl violet adsorption onto the adsorbent. baxsed on the kinetic data describing the adsorption process, three models pseudo-first-order, pseudo-second-order, and intraparticle diffusion were investigated. The results showed that the pseudo-second-order model provided the best fit. Thermodynamic parameters (∆G⁰, ∆H⁰ and ∆S⁰) indicated that the adsorption process is spontaneous, exothermic, and associated with a decrease in entropy. baxsed on the results, the hydroxyapatite-MIL-101(Al) composite can be considered an effective and efficient adsorbent with high removal efficiency and adsorption capacity for water purification applications.