Characterization and photocatalytic evaluation of polypropylene and polyethylene pellets coated with P25 TiO2 using the controlled-temperature embedding method

This study demonstrated a novel method used to coat polymeric pellets with titanium dioxide (TiO2) using simple and flexible equipment. In this method, TiO2 catalyst and polymeric pellets were dispersed in glycerine and heated to the melting point of the polymer, and then the system was cooled to room temperature, which resulted in the TiO2-embedded polymer. Degussa P-25 TiO2 was used as the catalyst, and pellets of polypropylene (PP) and low-density polyethylene (PE) were used as the polymeric supporting substrates. The coating adhesion was analyzed using an erosion test, and the photodegradation of the coated polymers was assessed through a photo-degradation test. The characterization of the TiO2-embedded polymer was performed using scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM/EDS), UV/Vis spectroscopy, diffuse reflectance UV-Vis spectra (DR/UV-Vis), thermogravimetric analysis (TGA) and differential thermal analysis (DTA), Fourier transforms infrared spectroscopy (FTIR), and stereomicroscopy. The photocatalytic activity was determined by analyzing the degradation of the model compound, 4-chlorophenol. The results indicated that the controlled-temperature embedding method led to well TiO2-coated polymeric pellets with a high activity and surface area. Thus, the controlled-temperature embedding method is a promising technique for surface engineering in the application of wastewater and drinking water treatment. (C) 2012 Elsevier B.V. All rights reserved.