Facile method for the synthesis of Fe3O4@HCP core–shell porous magnetic microspheres for fast separation of organic dyes from aqueous solution

Abstract

A novel type of porous magnetic microsphere (Fe₃O₄@HCP) was firstly synthesized just via one-step Friedel–Crafts alkylation promoted by FeCl₃. This universal and facile method to fabricate porous magnetic microspheres possesses distinct advantages such as cheap reactants, mild reaction conditions, a short reaction time and a simple post-treatment process. The core–shell spheres with a well-defined and uniform morphology possess a high Brunauer–Emmett–Teller specific surface area (770 m² g⁻¹). Besides, the magnetization saturation value reaches up to 18 A m² kg⁻¹ which is high enough to separate Fe₃O₄@HCP from aqueous solution. Fe₃O₄@HCP possesses fast adsorption kinetics and an excellent adsorption capacity for organic dyes: methyl orange (211 mg g⁻¹) and fuchsin basic (231 mg g⁻¹). The adsorption-saturated Fe₃O₄@HCP composites can be easily collected by an external magnetic field and reused at least 3 times after simple Soxhlet extraction and drying.