Simulated solar-light assisted photocatalytic ozonation of metoprolol over titania-coated magnetic activated carbon

A magnetically separable photocatalyst consisting of magnetic porous activated carbon with attached anatase TiO2 particles has been prepared and tested for the degradation of metoprolol (MTP) in aqueous solution. The synthesized photocatalyst (TiFeC) was characterized by nitrogen adsorption, XRD, FTIR, SEM, EDX and SQUID magnetometer. The obtained catalyst with a TiO2 composition of 61 wt.% (mostly anatase) had moderate surface area (BET surface of 331 m2 g-1) and volume of micropores and exhibited magnetic properties with saturation magnetization of 1.6 emu g-1 and neither remanent magnetization nor coercivity. The photocatalytic activity of TiFeC samples was tested by degrading MTP by simulated solar photocatalytic ozonation. The results were compared to those obtained with a commercial titania (Degussa P25) and by photolytic ozonation (i.e., absence of catalyst). Complete MTP removal and more than 60% TOC conversion were achieved after 3 h of photocatalytic ozonation of an aqueous solution containing as much as 50 mg L-1 MTP initial concentration. The reusability and stability of the catalyst were tested through a series of five photocatalytic ozonation experiments. Minor amounts of iron and titanium were leached out from the catalyst and the catalytic activity decreased to a very low extent with the reuse of the catalyst.