Preparation and adsorption behavior of amino-functionalized bridged organosilicas for the removal of Ag(I) from aqueous solutions

Novel p-phenylenediamine-bridged organosilica (PPDA-BOS-T) materials were synthesized via the co-condensation reaction assisted by tetraethyl orthosilicate (TEOS). These amino-functionalized organosilicas were characterized by Fourier transform infrared spectrometer, N 2 sorption, scanning electron microscopy, and transmission electron microscopy. The addition of TEOS played a positive role in the construction of the porous network structure of the bridged organosilicas. The saturation adsorption capacity for Ag(I) of the PPDA-BOS-T could reach 82.88 mg g –1 . The conformity to the Freundlich model indicated multilayer adsorption with active sites. Furthermore, the adsorption was followed well by the pseudo-second-order model, and the intraparticle diffusion was proved to be the rate-limiting step during the adsorption of Ag(I). Finally, the thermodynamic parameters including the change of free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) of adsorption were calculated.