Preparation of Fe-F/TiO₂ microsphere and its photodegradation mechanism for partially hydrolyzed polyacrylamide

With Span-80 as controlling agent, tetrabutyl orthotitanate (TBOT) as titanium source, Fe and F co-doped TiO₂ composite (Fe-F/TiO₂) microsphere was fabricated by hydrolysis-reflux method at low temperature. The structure and properties of as-prepared Fe-F/TiO₂ samples were characterized using XRD, FTIR, SEM, TG-DTA, BJH and UV-Vis DRS. The photocatalytic performance was evaluated by degrading partially hydrolyzed polyacrylamide (HPAM). The results show that mesoporous anatase Fe-F/TiO₂ microsphere is assembled with nanoparticles of which the diameter is 10-15 nm; Fe³⁺ can effectively promote the formation of anatase and inhibit the generation of rutile phase, which can result in high thermal stability; the specific surface area, pore volume, average pore diameter of catalyst are 145.11 m²/g, 0.26 cm³/g and 6.23 nm, respectively. In the process of photodegradation of HPAM, the synergistic effect of Fe³⁺ and F^- can enhance the photocatalytic performance which makes Fe-F/TiO₂ have the highest photocatalytic activity. The COD removal rate of HPAM (initial concentration of 500 mg/L) can be up to 81% and 74% when illuminated under ultraviolet (UV) and visible light for 120 min using 0.1 g of catalyst.