Preparation of magnetically separable composite photocatalyst: Titania coated magnetic activated carbon

摘要

In the present work, the embedded-type TiO_2/magnetic activated carbon (TiO_2/MAC) photocatalysts were prepared. The MAC support was manufactured by one-step method and the TiO_2 coated on the surface of MAC was prepared by sol-gel method. Its crystalline structural properties, morphology, magnetic performances and pore texture were characterized by XRD, SEM, TEM, ultraviolet-visible absorption spectra (Uv-vis), vibrating sample magnetometry (VSM) and N_2 adsorption isotherm. Characterization results showed that TiO_2 was highly dispersed on the surface of MAC support in the form of anatase with a particle size of 10 nm. Obtained TiO_2/MAC photocatalysts were applied to treatment of contaminant phenol in aqueous solution. The phenol removal percentage by TiO_2/MAC photocatalyst is as high as 94% after three cycles. In addition, photocatalytic degradation of phenol in water was examined using TiO_2/MAC photocatalysts. The results show that 4 wt% Fe_3O_4 was suitable to prepare the support of TiO_2/MAC composite. The phenol removal percentage by TiO_2/MAC photocatalyst is as high as 94% after three cycles. However, the adsorption capability of photocatalyst disappears after six cycles, while its phenol removal percentage via photodegradation is still as high as 60%. Meanwhile, the used TiO_2/MAC photocatalyst after six cycles still maintains good magnetic stability because the majority of magnetic particles are embedded into the bulk of carbon matrix. And the embedded structure could still meet the requirement of magnetic separation by an external magnetic field.