Synthesis of Schiff base-functionalized silica for effective adsorption of Re(VII) from aqueous solution

In the present work, high density active sites (C=N- groups) were introduced favorably onto the surface of silica by cross-linking reaction, leading to designing a new adsorbent and applying to the adsorption for Re(VII) from aqueous solutions. The novel adsorbent (SS-0.5h-0.5N-15GA) was characterized by SEM-EDS, TEM, FT-IR and XPS etc. The adsorption process fitted well with Langmuir isotherm the kinetic data fitted with pseudo-second order, and the experimental maximum adsorption capacity for Re(VII) was 270.13 mg/g at pH3.0, which was much higher than SS-0.5h-0.5N. Significantly, the reusability experiments demonstrated that SS-0.5h-0.5N-15GA exhibited excellent regeneration ability, with no obvious decline in adsorption capacity after four cycles. These results indicated that SS-0.5h-0.5N-15GA were promising for Re(VII) adsorption because of their higher rhenium adsorption capacity, rapid adsorption rate, low cost, and facile recovery process. (C) 2019 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.