Microwave-assisted one-pot rapid synthesis of mesoporous silica-chitosan composites for efficient recovery of rhenium(Ⅶ)

Abstract

• Mesoporous silica-chitosan composites were prepared by one-pot rapid microwave-assisted method. • The adsorbents were prepared without the use of expensive silane coupling agents or organic amine reagents. • The adsorbents have high adsorption capacity and selectivity for Re(VII). Rhenium (Re) is a rare element in the earth’s crust and has wide range applications in industry, its effective secondary enrichment plays a crucial role in environment and energy field. On the basis of economy and resource sustainability, we report a facile and rapid process to prepare chitosan (CS) functionalized mesoporous silica composites for recovery of Re by a one-pot microwave-assisted synthesis method. Schiff base groups inside the nanostructure were functioned as active sites for Re adsorption. A series of characterization analysis indicated that the optimal adsorbent (SS-KIT-6-M4-15-CS3) possessed mesoporous channel and retained the ordered morphology of mesoporous silica skeleton. The maximum adsorption capacity for Re(Ⅶ) of the as-prepared adsorbent reached 261.81 mg·g −1 at pH 4, higher than that of other reported adsorbents. The SS-KIT-6-M4-15-CS3 showed excellent regeneration performance after eight adsorption–desorption cycles, and exhibited high selectivity for Re(Ⅶ). The prominent adsorption performance was attributed to the chelation between C = N and ReO 4 ¯ according to FT-IR and XPS analysis. These findings showed encouraging potentiality of the adsorbent for recovering of Re(Ⅶ) in real industrial effluents.