Preparation of photo-grafted magnetic nano-silver composites and their catalytic studies on organic dyes

Abstract

More active and stable catalyst is needed for degradation of organic dyes in wastewater. A new kind of polymethyl methacrylate (PMMA) microsphere hybridized with Ag and Fe3O4 was developed as catalyst. PMMA microspheres were prepared by photoinitiated dispersive polymerization, and then acrylic acid (AA) was photo-grafted on the surface of microspheres with 365 nm UV light to prepare PMMA-AA microspheres whose carboxyl group was up to 164 × 1021 per microsphere. Under the effect of NaBH4, the Ag nanoparticles on the surface of PMMA and PMMA-AA microspheres were successfully modified with the help of carboxyl groups on the surface of PMMA and PMMA-AA microspheres. Fe3O4 particles were adsorbed onto the microsphere surface to obtain two kinds of microspheres (PMMA@Ag@Fe3O4, PMMA-AA@Ag@Fe3O4) for the catalytic reduction of methylene blue (MB) and rhodamine B (Rh-B), respectively. PMMA-AA@Ag@Fe3O4 microspheres exhibited excellently catalytic performance that the apparent rate coeffcients of MB and Rh-B were 0.045 s−1 and 0.036 s−1 respectively. The catalytic efficiency of PMMA-AA@Ag@Fe3O4 heterogeneous catalyst can reach 90% even after 8 cycles for MB. It has excellent catalytic performance, high non-selective adsorption and good reusability. Excellent catalytic performance, high non-selective adsorption and reusability even in the presence of mixed dyes.