Uranium biosorption from aqueous solution onto Eichhornia crassipes.

Uranium contamination in water sources poses significant environmental and health risks. Current methods for uranium removal often rely on costly or chemically intensive processes. Prior research has shown that certain plant materials can bind heavy metals through biosorption. However, the specific mechanisms and efficiency of uranium uptake by Eichhornia crassipes remain underexplored. This gap motivated researchers to investigate the potential of this aquatic macrophyte as a biosorbent. Understanding the pH dependence and kinetic behavior of uranium biosorption is essential for practical applications. The role of functional groups in the adsorption process has not been fully clarified in this context. No prior work had resolved the thermodynamic feasibility of uranium removal using Eichhornia crassipes. This study aims to address these uncertainties.

The goal of this study was to evaluate the biosorption capacity of Eichhornia crassipes biomass for uranium removal from aqueous solutions. Researchers aimed to determine the optimal pH for maximum U(VI) uptake. They also sought to understand the kinetics and thermodynamics of the biosorption process. The study aimed to identify which functional groups on the biomass are involved in uranium binding. By analyzing the equilibrium time, the team wanted to assess the practicality of this biosorbent for real-world applications. The researchers also intended to compare the Langmuir and Freundlich isotherm models to determine the best fit for the data. This work aimed to provide a foundation for using Eichhornia crassipes in environmental remediation. The study sought to confirm whether biosorption is a spontaneous and endothermic process.

The study used batch experiments to test uranium biosorption onto nonliving Eichhornia crassipes biomass. Researchers varied pH levels to determine the optimal condition for U(VI) removal. They measured the adsorption rate over time to identify the equilibrium point. The pseudo-second-order kinetic model was applied to describe the adsorption process. The Langmuir and Freundlich isotherm models were compared to assess adsorption capacity. Thermodynamic parameters were calculated to evaluate the spontaneity and enthalpy of the process. Fourier transform infrared spectroscopy was used to identify functional groups involved in biosorption. X-ray photoelectron spectroscopy confirmed the presence of amino, hydroxyl, and carboxyl groups.

The highest U(VI) removal occurred at pH 5.5, indicating strong pH dependence. Equilibrium was reached within 30 minutes, showing rapid biosorption kinetics. The pseudo-second-order model best described the adsorption process. The Langmuir isotherm model provided the best fit for the data, with a maximum adsorption capacity of 142.85 mg/g. Thermodynamic calculations revealed the process was spontaneous and endothermic. Functional group analysis suggested amino, hydroxyl, and carboxyl groups were involved. Coordination and ion exchange mechanisms were proposed as the primary binding forces. These findings suggest Eichhornia crassipes is a highly effective biosorbent for uranium.

The study found that Eichhornia crassipes biomass effectively removes uranium from aqueous solutions. The optimal pH for U(VI) biosorption was identified as 5.5. The process reached equilibrium in 30 minutes, indicating rapid adsorption. The Langmuir model best described the biosorption isotherm. Thermodynamic data confirmed the process was spontaneous and endothermic. Functional groups such as amino, hydroxyl, and carboxyl were likely involved. Coordination and ion exchange mechanisms were proposed as key binding forces. The authors conclude that Eichhornia crassipes is a promising biosorbent for uranium removal.