Removal of Fe(III) from ethanol solution by silica-gel supported dendrimer-like polyamidoamine polymers

The adsorption properties of silica-gel supported hyperbranched polyamidoamine dendrimers (SiO2-G1.0, SiO2-G2.0 and SiO2-G3.0) for the removal of Fe(III) from ethanol solution have been investigated. The effect of adsorbent mass, contact time, initial Fe(III) ion concentration, and temperature have been demonstrated. The adsorption kinetics of the three adsorbents was well described by the pseudo-second-order model. Langmuir isotherm model was more suitable to describe the equilibrium data, and suggested the monolayer adsorption. The mean free energy calculated from D-R isotherm model demonstrated the adsorption processes of was preceded by physical adsorption or chemical adsorption for different generation product in different temperatures. Thermodynamic parameters demonstrated that the adsorption process was exothermic, spontaneous, and random increasing process with the increase of temperature. The adsorption mechanics for Fe(III) is was greatly affected by the solvent. Furthermore, the desorption rate of the SiO2-G1.0 maintained more than 90%, and reflected excellent reusability.