Spherical montmorillonite-supported nano-silver as a self-sedimentary catalyst for methylene blue removal

Abstract Supported metal nanoparticles using various substrates have been proven as a highly efficient approach for solving the problems of aggregation and recyclability of metal nanoparticles. However, the reusability procedure often involved the abundant devices, which obviously increased the cost and heavily limited the large-scale application of metal nanoparticles. In this work, spherical montmorillonite was used firstly as the substrate for supporting silver nanoparticles on its surface through polydopamine chemistry method. The loading of silver nanoparticles with 40 nm in diameter was 15.2 wt% and the specific surface area of this prepared spherical montmorillonite supported silver nanoparticles catalyst was 45.3 m2/g, giving the catalyst an optimized apparent reduction rate constant k of 1.22 min−1 for the reduction of methylene blue. Furthermore, the prepared catalyst with quickly self-sedimentary property in aqueous solution were conveniently recovered and reused without any devices involves. The spherical morphology and catalytic performance of prepared catalyst were almost unaltered after 5 cycles. Our research aims at opening a new avenue to easily realize the reusability of silver nanoparticles through using the substrate with the self-sedimentary property.