Bifunctional Fe3O4 nanoparticles as magnet and inducer in bioextruded fabrication of starch-based composite with hierarchical pore architecture

Starch (St) was used as green and renewable matrix (> 80%, db) for the preparation of Zn-St-MOCP/nFe(3)O(4) composite via bioextrusion. Bifunction of Fe3O4 NPs as magnet and pore-inducer was confirmed and could be more homogeneously embedded in the St-based framework with hierarchical porous structure via SEM-EDS mapping. For the nFe(3)O(4)-induced microstructure of Zn-St-MOCP/nFe(3)O(4) composite, submicronic pores and nanopores were observed with Fe3O4 NPs onto the inner surface of micron channels. According to the XPS, XRD, FTIR, TGA analyses, it is probably due to the coordination between Fe3+/2+ and Zn2+/hydroxy groups and the recombination of St chains in crystalline/amorphous zones interfered by Fe3O4 NPs. Saturation magnetization value was measured with an excellent separation behavior. Seven kinetic equations were conducted for the fitting of dye adsorption data. Overall, the nFe(3)O(4)-assisted bioextrusion strategy is developed for the continuous fabrication of bio-based materials with rapid magnetic separation and hierarchical-pore architecture promising in practical adsorption.

Automated summary

Starch was used as a green and renewable matrix for the preparation of Zn-St-MOCP/nFe(3)O(4) composite, with Fe3O4 NPs serving as both magnet and pore-inducer. The composite exhibited a microstructure with submicronic and nanopores, showing promising potential for practical adsorption with rapid magnetic separation.