TiO2-doped natural hematite as effective and recyclable catalyst for the photodegradation of Orange G dye

Abstract A novel photocatalyst, natural hematite supported TiO 2 (TiO 2 /Nat-Hem), was successfully synthesized by chemical vapor deposition method. The TiO 2 /Nat-Hem catalyst was characterized by different physicochemical analyses such as XRD, BET, XRF, FT-IR and SEM–EDX. XRD results indicated the presence of titanium oxide in two phases of anatase and rutile. On the other hand, BET analysis showed that the specific surface area of natural hematite (Nat-Hem) increased from 7.83 to 37.52 m 2 /g, demonstrating the attachment of TiO 2 on its external surface. In addition, SEM–EDX analysis mentioned that 7.86 wt% of titanium element was dispersed on the surface of the prepared catalyst, while the FT-IR spectrum of prepared catalyst indicated the existence of (Ti–O) groups. The catalytic performance of the TiO 2 /Nat-Hem catalyst has been evaluated in the photodegradation of Orange G (OG) dye. The influence of experimental parameters (H 2 O 2 concentration, pH solution and deposited titanium content) on the kinetics degradation of the dye was considered. A percentage of OG discoloration equal to 95% was obtained under optimal conditions (0.01 mol/L H 2 O 2 , pH close to 5 and a deposited titanium content of 13.78%). Monitoring of the disappearance of OG coloring during reaction was performed by measuring the TOC and COD parameters. The TiO 2 /Nat-Hem catalyst exhibits high stability after reuse for three consecutive OG degradation cycles. Natural hematite has proven to be a suitable oxidant and support for depositing well-dispersed and very active TiO 2 phases.