A magnetic mesoporous SiO₂/Fe₃O₄ hollow microsphere with a novel network-like composite shell: synthesis and application on laccase immobilization

The magnetic mesoporous SiO₂/Fe₃O₄ hollow microspheres, which have a unique network-like shell constructed with magnetic Fe₃O₄ nanorods and mesoporous SiO₂, were successfully prepared by the co-condensation of tetraethoxysilane in the presence of cetyltrimethylammonium bromide and 1,3,5-triisopropylbenzene. The composite microspheres were utilized as supports for laccase immobilization. The composite microsphere has high surface area (772 m² g⁻¹) and large pore volume (0.83 cm³ g⁻¹). The obtained microspheres exhibit relatively high saturated magnetization (13.6 emu g⁻¹). The composite mesoporous microspheres used to immobilize laccase as support have a notable laccase immobilization (689 mg g⁻¹) for per gram pure mesoporous SiO₂ in the composite microspheres, which is much larger than those reported in the literature. The activity of immobilized laccase has good pH stability and thermal stability. It is further demonstrated that the immobilized laccase exhibited a good catalytic performance when they were used to react with the 2,4-dichlorophenol solution. The degradation rate and removal rate of the 2,4-dichlorophenol is 52.31 and 81.64 %, respectively.