Metal organic framework composite based on CuBTC/SPION for application in methylene blue adsorption

In this work, a composite (CuBTC/superparamagnetic iron oxide nanoparticles [SPION]) based on copper, benzene-1,3,5-tricarboxylic acid (CuBTC) and SPION was synthesized by electrochemical method for the magnetic separation of methylene blue (MB) from aqueous solutions. The synthesis of the proposed composite was carried out under various experimental conditions from 1.4 to 5.4 V for 1–5 h and subsequently studied using different techniques. Scanning electron microscopy showed a granular structure, whereas Brunauer–Emmett–Teller results revealed a well-developed surface area of around 182 m² g⁻¹. Fourier transform infrared confirmed the presence of functional groups characteristic to CuBTC and Fe₃O₄, whereas X-ray diffraction revealed the phase structure of CuBTC 1D, CuBTC 3D, and Fe₃O₄ in the obtained composite. Based on the experimental results, the sample synthesized under a potential of 1.4 V for 5 h was selected for MB adsorption studies in the function of adsorbent mass, contact time, solution pH, ionic strength, initial concentration, and temperature. The maximum adsorption capacity was 681 mg g⁻¹, and the adsorption undergoes the Redlich–Peterson and Sips isotherm model. The results obtained for CuBTC/SPION indicate that the nanocomposite is a promising adsorbent for removing MB in synthetic dye water and wastewater.