Polyamidoamine dendrimers modified silica gel for uranium(VI) removal from aqueous solution using batch and fixed-bed column methods

Different generations of modified silica gel with polyamidoamine (PAMAM) dendrimers were synthesized. The adsorbents were characterized using Fourier transform infrared, scanning electron microscopy with energy dispersive X-ray spectroscopy thermal gravimetric analysis and porous structure analysis. The uptake behavior of Si-6G PAMAM toward Li(VI) at different experimental conditions of pH, time, temperature and concentration was studied using batch mode. The maximum adsorption capacity of Si-6G PAMAM was 303.03 mg as described effectively by Langmuir isotherm model. Kinetics and thermodynamics studies of U(VI) adsorption onto Si-6G PAMAM showed an endothermic pseudo-second-order adsorption process. The experimental results in the column method were described by Thomas and Yoon-Nelson models under different operating conditions.