Evaluation of the photocatalytic degradation of pre-treated palm oil mill effluent (POME) over Pt-loaded titania

This paper reports the photocatalytic degradation of pre-treated palm oil mill effluent (POME) over a Pt-doped titania photocatalyst. Pt loading on the titania was varied from 0.25 to 1.0 wt% via alcohol reduction of chloroplatinic acid (H₂PtCl₆). XRD characterization of the photocatalysts showed that the photo-active anatase phase was still intact after the photocatalyst synthesis while the XPS spectrum confirmed that the deposited Pt was free from the Cl and existed as Pt⁰ and Pt⁴⁺. In addition, the UV-vis diffuse reflectance measurement indicated an improved light energy absorption in the visible light spectrum. Moreover, the band gap energy (3.16-3.17 eV) was reduced when titania was doped with Pt, compared to the pristine titania with 3.20 eV. The 0.5 wt% Pt/TiO₂ photocatalyst offered the most effective degradation of pre-treated POME under the irradiation of 100 W of UV light (10%) and also visible light (11%), respectively, over a loading of 0.2 g/L. Significantly, the maximum 0.5 wt% Pt/TiO₂ photocatalyst loading determined from the current work was 1.0 g/L.