Novel Fe₃O₄@TiO₂@PB ternary composites for photocatalytic magnetorheological polishing of ceramic dentures and photocatalytic degradation of pollutants

Ceramic dentures differ from those produced by additive manufacturing, and manual polishing is employed for ceramic dentures due to their hard-brittle nature, complex shapes, and thin-walled structures with thicknesses less than 1.0 mm. This presents challenges for the medical and manufacturing industries. To address these challenges, we prepared a novel ternary composite of Fe 3 O 4 @TiO 2 @PB (Prussian blue) to establish a photo-Fenton system. This composite enhances the transport of photogenerated electrons and facilitates the generation of radicals, demonstrating high photocatalytic activity for the polishing and degradation of pollutants without the need for sacrificial agents. Meanwhile, Fe 3 O 4 @TiO 2 @PB was utilized to develop a new photocatalytic magnetorheological polishing slurry. The slurry consisted of sorbitol, hydrogen peroxide, Fe 3 O 4 @TiO 2 @PB, and ceria (0.025 wt. %). After polishing, the surface roughness (Sa) decreased from 5.538 to 0.081 μm, representing a reduction of 98.54 % compared to the pristine surface. Due to photogenerated hydroxyl radicals, the Si-OH and Li-OH bonds can be created on the surface of the ceramic dentures, facilitating defects removal. Before and after polishing, the ceramic dentures enhanced the inhibition rates of Escherichia coli and Staphylococcus aureus from 50 % to 74 % and from 49 % to 80 % over the course of one day, respectively. Through irradiation with simulated sunlight, Fe 3 O 4 @TiO 2 @PB generates electrons, holes, and hydroxyl radicals, leading to the degradation of amoxicillin (AMOX) and polysorbate (PS20) by up to 99 % within 60 min. Additionally, Fe 3 O 4 @TiO 2 @PB was successfully separated and reused from the developed slurry. Therefore, the designed and developed novel ternary composite, Fe 3 O 4 @TiO 2 @PB, achieves photocatalysis, photodegradation, and recycling, offering new solutions for the medical, manufacturing, and environmental industries.