Photoetching of Immobilized --PVC Composite for Improved Photocatalytic Activity

Commercially acquired TiO 2 photocatalyst (99% anatase) powder was mixed with epoxidized natural rubber-50 (ENR 50 )/polyvinyl chloride (PVC) blend by ultrasonication and immobilized onto glass plates as TiO 2 -ENR 50 -PVC composite via a dip-coating method. Photoetching of the immobilized TiO 2 -ENR 50 -PVC composite was investigated under the irradiation of a 45 W compact fluorescent lamp and characterized by chemical oxygen demand (COD) analysis, scanning electron microscopy-energy dispersive X-ray (SEM-EDX) spectrometry, thermogravimetry analysis (TGA), and fourier transform infrared (FTIR) spectroscopy. The BET surface area of the photoetched TiO 2 composite was observed to be larger than the original TiO 2 powder due to the systematic removal of ENR 50 while PVC was retained within the composite. It also exhibited better photocatalytic efficiency than the TiO 2 powder in a slurry mode and was highly reproducible and reusable. More than 98% of MB removal was consistently achieved for 10 repeated runs of the photo-etched photocatalyst system. About 93% of the 20 mg L −1 MB was mineralized over a period of 480 min. The presence of , , and Cl − anions was detected in the mineralized solution where the solution pH was reduced from 7 to 4.