Removal of uranium from water at natural pH: characterization and utilization of modified banana peel carbon

This study presents a cost-effective and sustainable approach for the removal of uranium from aqueous solutions at natural pH using a bio-waste-derived adsorbent. Banana peel carbon was modified with aluminum and potassium hydroxide to synthesize a novel adsorbent, aluminum and potassium hydroxide-coated carbon (APHC). Comprehensive characterization of the adsorbent was conducted using Brunauer–Emmett–Teller surface area analysis, scanning electron microscopy, energy-dispersive X-ray fluorescence, Fourier transform infrared spectroscopy, and wet chemical analysis. Batch adsorption experiments were performed to investigate the effects of key operational parameters, including solution pH, initial uranium concentration, adsorbent dosage, contact time, temperature, and sample volume. The adsorption process followed a pseudo-second-order kinetic model and conformed to both Langmuir and Freundlich isotherms, with a maximum adsorption capacity of 10 mg/g, indicating favorable multilayer adsorption behavior. Intra particle diffusion analysis revealed a multi-step adsorption mechanism. Application of APHC to real groundwater samples demonstrated uranium removal efficiencies exceeding 99%, without causing significant changes in water chemistry. These findings underscore the potential of APHC as a low-cost, environmentally friendly adsorbent for efficient uranium remediation in water treatment applications.