Hierarchical self-assembly of polyphenolic functionalized magnetic superstructure for enhanced removal of organic dyes

Abstract

Nanocomposites play critical roles in catalytic oxidation, wastewater treatment, and other chemical engineering fields. Therefore, the strategies to develop multifunctional nanocomposite systems through chemical synthesis, physical doping, and assembly have been explored. The existing challenges including fussy preparation processes and conditions limit the applications of multifunctional nanocomposite systems. Here we nano-engineer a versatile polyphenolic functionalized magnetic core-satellite superstructure (referred to as PfMCSP) using the metal-phenolic mediated fast self-assembly in which Fe3O4 and polyphenolic functionalized TiO2 are used as the core and satellite, respectively. The PfMCSP presents a high equilibrium adsorption capacity (qe) of 210.68 mg/g and achieves ultrafast adsorption (more than 89% of qe within 2 min) of organic dyes (methylene blue, rhodamine B, and toluidine blue) through multiple interactions. Moreover, the adsorption process accelerates the photocatalysis (TiO2) and Fenton reaction (Fe3O4) synergistic to remove organic dyes, resulting in more than 95% degradation of methylene blue (160 mg/L) within 90 min and maintaining an 80% degradation after 5 recycles. This facile and rapid synthesis strategy for PfMCSP based on the encapsulation of Fe3O4, TiO2, and natural polyphenol, is envisaged to deliver a new path for practical wastewater treatment applications.