Sulfoethyl functionalized silica nanoparticle as an adsorbent to selectively adsorb silver ions from aqueous solutions

A novel adsorbent was fabricated via grafting sulfoethyl groups on silica nanoparticles to achieve selective adsorption of silver ions from aqueous solution. Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR) spectroscopy and thermogravimetric analysis (TGA) were used to characterize the adsorbent. The influence of pH, initial concentration, adsorption time and interfering metal ions was investigated. The adsorption equilibrium time was about 60 min and the adsorption capacity for silver ion was 21.9 mg g−1 at pH 6. The adsorption isotherms fitted well with the Langmuir isotherm and the obtained kinetic data support a pseudo-second order adsorption behavior for the functionalized silica nanoparticles. The adsorption mechanism is the chelating interaction. The functionalized silica nanoparticle showed good selectivity to adsorb the silver ions from aqueous solution. The adsorbent could be of great potential as a new class of adsorbent for silver ions.