Magnetite Nanoparticle/Copper Phosphate Nanoflower Composites for Fenton-like Organic Dye Degradation

A fast and sustainable technique in catalytically degrading organic dyes under flow is reported. It involves the use of three different applications of the high-shear and intense micro-mixing vortex fluidic device (VFD), including material fabrication, reactor coating, and material “banding”. The active catalytic material is a composite of magnetite nanoparticles and Cu₃(PO₄)₂ nanoflowers (MNPCuNFs), 8–10 μm in diameter, which are generated in the VFD within 30 min. MNPCuNFs magnetically and centrifugally held against the surface of the rapidly rotating tube in the VFD have enhanced catalytic activity in degrading four different organic dyes under real-time monitoring with at least a fivefold increase in the degradation efficiency compared to that in the batch processing. To further improve the platform performance, the VFD tube reactor was chemically modified, incorporating a thin layer of silica-activated carbon xerogel coating which behaves synergistically with the nanoflowers. This coated tube is highly stable and reusable, dramatically increasing the degradation efficiency by about 30-fold relative to using batch processing. Integrating an ultraviolet–visible spectroscopy-based probe allows real-time monitoring of the reaction and also provides a direct tool to evaluate the coating layer post reaction. This study provides a rational design of hybrid materials and the use of a modified VFD tube reactor toward efficient degradation of organic dyes in real time.