Silica-Based 1,3-Diphenyl-1,3-Propanedione Composites: Efficient Uranium Capture for Environmental Remediation

Introduction This study synthesizes and characterizes a novel hybrid composite, SG-dpm, to capture UO22+ ions from water. The composite has successfully formed by hosting covalently diphenylmethane-1,3-dione (dpm) within an inorganic silica gel matrix, showing promising potential for environmental remediation and nuclear waste management.Methods The preparation involved the reaction of tetraethylorthosilicate (TEOS) with diphenylmethane-1,3-dione (dpm) under acidic conditions, resulting in white solids. The doped composite was characterized by Fourier Transform Infrared Spectroscopy (FTIR), revealing the presence of siloxane and Si-O-C bonds. The application of SG-dpm for capturing UO22+ ions from water was investigated, showing a shift in FTIR peaks and confirming the formation of SG-dpm-UO22+ as inner-sphere complexes. Scanning Electron Microscopy (SEM) revealed a non-uniform distribution of particles, essential for consistent behavior in applications such as adsorption.Results and Discussion Batch sorption experiments demonstrated temperature-dependent sorption behavior with increased efficiency at higher temperatures (T = 55 degrees C). The study also explored the influence of pH and initial concentration on UO22+ sorption, revealing optimal conditions at pH 5 and lower initial concentrations (1.0 mg L-1). Kinetic studies using pseudo-second-order models indicated a high efficiency of UO22+ ion removal (99%) as a chemisorption process. Intraparticle diffusion models highlighted three distinct sorption stages. Sorption isotherm studies favored the Langmuir model, emphasizing monolayer adsorption. The thermodynamic analysis suggested an endothermic (circle times H = + 16.120 kJ mol-1) and spontaneous (circle times G = -25.113 to - 29.2449 kJ mol-1) sorption process. Selectivity studies demonstrated high efficiency in capturing Cu2+, Co2+, and Cr3+ ions, high degree selectivity of UO22+ ions (74%), moderate efficiency for Fe3+ and Zn2+, and lower efficiency for Pb2+, Ni2+, and Cd2+, and poor efficiency for Mn2+ ions.In Conclusion , SG-dpm exhibits promising potential for selective UO22+ ion removal, demonstrating favorable characteristics for various applications, including environmental remediation and nuclear waste management.