Preparation, Characterization and Adsorption into Aqueous Solutions of Polyethyleneimine-Coated Silica Nanoparticles

Abstract

In this study, polyethyleneimine-coated silica nanoparticles (PEI-SiNP) were used to prepare apolymeric material that can effectively and selectively adsorb Au(III) from aqueous solutions. For thispurpose, silica nanoparticles were firstly reacted with (3-glycidyloxypropyl)trimethoxysilane (GPTMS) toachieve epoxy functionality. The structures of the silica nanoparticles (SiNP), silica nanoparticles withepoxy functionality (E-SiNP) and polyethyleneimine-coated silica nanoparticles were determined usingATR-FTIR (Attenuated Total Reflectance Fourier Transform Infrared) and XPS (X-Ray PhotoelectronSpectroscopy), while their thermal properties were characterized using thermogravimetric analyses (TGA).The Au(III) ion-binding capacity of the PEI-SiNP adsorbent nanocomposite that contain high levels ofimine was investigated. The effects of the interactions between pH, contact time, and foreign metal ionson adsorption were tested to determine the optimum conditions. The optimum contact time was 3 hoursat pH 2. The adsorption capacity of the adsorbent nanocomposite prepared for Au(III) was found to be116.27 mg/g. The Langmuir and Freundlich isotherms were used to determine the adsorption behaviorsand the Langmuir isotherm model was selected as the best fit model (R2: 0.997). The prepared PEI-SiNPadsorbent nanocomposite showed a high selectivity for the Au(III) ion even when different metal cationssuch as Cu(II), Cd(II), and Pb(II) were present.