study of a magnetic photocatalyst based on hemin with axial ligand and its degradation under visible light

an investigation was conducted on hemin modified with axial ligand loaded onto magnetic carriers which created a kind of visible-light activated photocatalyst with good magnetic property. this photocatalyst exhibits excellent photo-degradation performance and can be readily reclaimed in the degradation of bis-phenol a (bpa) in aqueous solution under visible light. the catalysts were characterized by thermal gravimetric analysis (tg), transmission electron microscopy (tem), magnetometer (vsm) and ir spectra. the effects of different operation parameters on the photocatalytic reaction have also been investigated. the highest degradation ratio reached up to 94.75% after 6 hours under optimized operation conditions. moreover, the photocatalyst could be readily reclaimed by magnetic separation with an external magnetic field and when it was reused for 5 times under the same conditions, the degradation ratio of bpa solution during the last time was still higher than 90%. possible mechanism on bpa degradation was also investigated based on a series of control experiments. the main intermediate of bpa degradation was monitored by gc/ms analysis.