Valorization of banana peel waste into Zr-MOF@AC composite for sustainable methyl orange removal from water with kinetic, isothermal and thermodynamic insights
Faisal Khan, Khalil Ahmad, Waseem Razzaq Khan, Muhammad Abdullah, Manish K. Rawal, Aqeel Ahmed Shah, Ali Dad Chandio, Muhammad Kashif, Saqib Kamal, Mika Sillanpää, Saleh Alfarraj
Abstract
Zr-based metal-organic framework (Zr-MOF) and its composite (Zr-MOF@AC) with activated-carbon (AC) were formed via solvothermal techniques at room temperature using safe solvent water. Activated-carbon prepared from agricultural waste (banana-peels) to utilize this unwanted waste to remove toxic pollutant from water. Both Zr-MOF and its composite were successfully characterized using advance spectroscopic techniques. Fourier Transform Infrared Spectrophotometer analysis confirms the successful formation of both adsorbents due to the functional-groups (Zr-O) peaks at 743 cm −1 and X-ray Diffraction confirms the degree of crystallinity and phase composition. The external structure, dimension of particles, and chemical breakdown of the produced materials were displayed by Field Emission Scanning Electron Microscopy and Energy Dispersive X-ray and thermal stability were checked using thermogravimetric analysis. The composite gives maximum performance at pH= 6 with amount of 0.01 g MOF and composite, achieving maximum adsorption capacity up-to 280.08 and 243.9 mg.g −1 respectively, within 45 min. The best fitted kinetics is pseudo second-order model for Zr-MOF and composite. The Langmuir model is best fitted for the adsorption of the MO on the composite, according to isothermal study. Thermodynamic study shows that reaction is spontaneous and exothermic. This study demonstrates the promise of an inexpensive, environmentally acceptable nanocomposite for the elimination of colours from our surroundings. This study confirms the potential of low-cost, eco-friendly composite for dyes removal from environment. • Zr-MOF@AC composite was synthesized using banana peel–derived activated carbon. • The composite exhibited adsorption capacity of 280.08 mg g⁻¹ MO dye at pH 6. • Adsorption followed the Langmuir isotherm and pseudo-second-order kinetic model. • Thermodynamic analysis revealed a spontaneous and exothermic adsorption process. • The composite showed excellent reusability with > 90 % efficiency after six cycles.