TiO2/Fe3O4 Nanoparticles Embedded Thermo Responsive Composite Gel Beads for Water Treatment

Because of its environment-friendly properties, TiO₂ nanoparticles can be used for wastewater treatment. However, although the reaction rate is high, separation and recovery process of TiO₂ nanoparticles from the treated water is required after the reaction. To overcome the disadvantage, here we propose to prepare both TiO₂ and Fe₃O₄ nanoparticles embedded thermo-responsive composite gel beads. In the composite, poly(N-isopropylacrylamide) (PNIPAM) and calcium alginate were used as thermo-responsive polymer and structure support polymer, respectively. Here, Fe₃O₄ nanoparticles will be used to achieve localized heating. If AC magnetic field is applied for the composite intermittently, the composite beads will swell and shrink repeatedly and it will achieve the promoted diffusion of substrates and products through the composite.

The composites were prepared using single tube nozzle by modifying the simple process to prepare thermo-responsive capsule reported in our previous report. The obtained samples were characterized by examining their thermo-responsive property, photocatalytic activity and localized heating property. The experimental results showed that localized heating of thermo-responsive bead containing Fe₃O₄ was also achieved without raising a bulk solution temperature by applying alternative current (AC) magnetic field. The simulation based on the characterization experiments on thermo-responsive property, photocatalytic activity and localized heating property proved the effectiveness of thermo-responsive pumping to improve the phtocatalytic activity of TiO₂ nanoparticle embedded in the composite gel.