Preparation And Properties Of Polypyrrole-TiO₂Composite Magnetic Photocatalyst

Nano-titanium as a widely used photocatalytic material has a great potential forapplication in the sewage treatment. The emergency of magnetic photocatalyst solved theproblem that not only suspended TiO₂is agglomerates easily, recycle difficulty, but also thelow photocatalytic activity of laden TiO₂. In this paper, the magnetic particles which ismodified by silane coupling agent NQ-54is magnetic nuclear, then coated TiO₂on it bysol-gel method, finaly obtained the polypyrrole-TiO₂composite magnetic photocatalyst by insitu oxidation polym erization. This novel photocatalytic material not only has a higherphotocatalytic activity under ultraviolet light, also exhibit good photocatalytic performanceunder sunlight, and under the external magnetic field, the magnetic composite material caneasily separated and recovered, is a new kind of composite materials which with potential fordevelopment. The main content was the following three parts:1. Magnetic matrix of Fe₃O₄and Mn_0.4Zn_0.6Fe₂O₄were prepared respectively byco-precipitation and sol-gel prepared methods, then by adding different doses of silanecoupling agent to prepare the modified magnetic matrix. The samples were characterized byFT-IR, XRD, SEM, TEM, VSM and some more methods. The results show that: comparedwith the ferrite samples which were not modified by silane coupling agent, the particle size ofmodified ferrite samples have significantly reduced; the iron leaching of modified ferrite wasdecreased in a strong acid, the acid stability was increased; the saturation magnetization of themodified ferrite increased, when the amount of the silane coupling agent sdded was1.51%byvolume, the magnetic was the best.2. TiO₂samples were prepared by Sol-gel method, TiO₂-polypyrrole composite materialswere prepared by in situ oxidation polymerization, the impact of the ratios of pyrrole andTiO₂on the photocatalytic properties of TiO₂-polypyrrole composite materials were studiedby the degradation of methyl orange. Using FT-IR, XRD, UV-visible spectroscopy to characterized the samples. The results show that: the coating of polypyrrole can reduce theband gap of the TiO₂, when the pyrrole dosage is0.06mL, the band gap of TiO₂dropped to2.90ev; when amount of pyrrole added, the degradation rate of methyl orange of thecomposite samples were increased in UV light and sunlight, the degradation rate can up to95%.3. Preparation of the composite magnetic photocatalytic which the modified magnetic asthe nuclear matrix, the polypyrrole-TiO₂as the shell, Study the photocatalytic activity throughthe photocatalytic degradation of methyl orange, and study their recycling performance. UsingXRD, VSM, UV-visible spectroscopy to characterized the samples. The results show that:composite materials have both photocatalytic and magnetic properties; recyclingphotocatalytic degradation showed that the degradation rate of the composite magneticphotocatalyst reached about90%, the recovery rate was maintained more than97%.