Efficient uranium capture from water with date palm seed biomass: green remediation

Uranium pollution in water systems, particularly in areas affected by mining and industrial activity, poses serious environmental and public health hazards. Conventional methods of extracting uranium from aqueous solutions are frequently expensive and energy-intensive and can produce secondary waste. As a result, sustainable, low-cost uranium removal methods, such as biosorption with natural materials, have gained popularity. This study effectively explored the capturing behavior of uranium ions U(VI) onto date palm seed biomass (DPSB) under various experimental settings, emphasizing temperature, pH, and starting concentration. The study found that temperature significantly impacted sorption efficiency, which increased from 70% at 25 °C to 76% at 55 °C, indicating an endothermic process. The equilibrium period decreases considerably with temperature, from 90 min at 25 °C to 60 min at 55 °C, indicating quicker kinetics at higher temperatures. The pseudo-second-order kinetic model fit the data well across all temperature settings (R² > 0.99), with a maximum sorption rate constant (k₂ = 0.148522) seen at 45 °C, followed by a minor drop. pH has a substantial impact on uranium ion U(VI) sorption, with the highest efficiency recorded at pH = 7 (72%). The pseudo-second-order model's accuracy is proven by strong correlation coefficients (R² > 0.99) at all pH values, with the greatest match at pH = 5 and 11. Initial concentration experiments showed that increasing the U(VI) concentration increased sorption performance. The pseudo-second-order kinetic model revealed important insights into the sorption mechanisms, demonstrating that chemisorption was the rate-limiting step. At a concentration of 10 mg L^-1, the rate constant k₂ was 0.089751 g mg^-1 min^-1 at pH = 5, and the equilibrium sorption capacity q_{e cal} = 3.527337 mg g^-1 was consistent with the actual result (q_{e exp} = 3.5 mg g^-1), validating the model's trustworthiness. Lower concentrations are better suited for the Langmuir model (R² = 0.9995), indicating monolayer adsorption with moderate binding strength (b = 1). The Freundlich model (R² = 0.9981) was more suitable for larger concentrations because of the heterogeneous biomass surface. However, its negative 1/n value showed limitations under the specified conditions. The findings of this research provide a sustainable and environmentally friendly solution to mitigate uranium contamination.