Investigation of Uranium Adsorption Behavior of Al-Doped ZnO/PVDF Nanofibers Using Response Surface Methodology

In this study, aluminum-doped zinc oxide (Al:ZnO)/poly(vinylidene fluoride) (PVDF) composite nanofibers were synthesized via electrospinning and evaluated as adsorbents for U(VI) removal. The adsorption process was optimized using Response Surface Methodology (RSM) based on a Central Composite Design (CCD). The effects of key parameters were systematically investigated. The quadratic model developed through RSM exhibited an excellent coefficient of determination (R² = 0.9846), confirming a strong correlation between experimental and predicted values. The results indicated that pH and initial uranium concentration significantly influenced adsorption efficiency. Optimal conditions were identified at pH 5.26, temperature 59.1 °C, an initial U(VI) concentration of 124.7 mg L-1, and an adsorbent dosage of 0.0025 g. Under these conditions, the maximum experimental adsorption capacity reached 132.7 mg/g. The adsorption behavior followed the Langmuir isotherm model, suggesting monolayer adsorption on homogeneous siteswith a theoretical maximum capacity of 138.5 mg g-1, which is in close agreement with the experimental value. Thermodynamic parameters revealed that the process was spontaneous and endothermic. These findings demonstrate that electrospun Al:ZnO/PVDF nanofiber composites are promising adsorbents for uranium remediation and emphasize the effectiveness of RSM for adsorption process optimization.