One-step synthesis of chitosan-magnetite composite microparticles by evaporation-induced assembly and subsequent silver loading for catalytic application

摘要

Chitosan-magnetic composites are widely used as catalyst and as adsorbent for various metal ions. In this work, microparticles containing magnetite nanoparticles dispersed in ionically cross-linked chitosan matrix were prepared in one single step by spray drying two separate colloidal solution consisting of chitosan, magnetite NPs and sodium tri-polyphosphate together using a three-fluid nozzle. Subsequently, silver ions were adsorbed on these composite microparticles and reduced. The composite was characterized using SEM, HR-TEM, SQUID, XRD, TGA and FTIR techniques. Finally, the catalytic activity of silver nanoparticle loaded chitosan-magnetite composite microparticles were tested on the reduction reaction of 4-nitrophenol to 4-aminophenol by sodium borohydride.