Solid-phase photocatalytic degradation of polyethylene plastic under UV and solar light irradiation

This paper investigated solid-phase photocatalytic degradation of polyethylene (PE) plastic with TiO2 in the ambient air under solar and ultraviolet light irradiation. The photodegradation of the composite plastic was compared with that of pure PE through weight loss monitoring, scanning electron microscopic (SEM) analysis, gas chromatography (GC), FT-IR spectroscopy and X-ray photoelectron spectroscopy (XPS). PE-TiO2 composite plastic can be efficiently decomposed and the main products are CO2 and water. The weight-loss of PE-TiO2 (1 wt%) film reached 42% under solar irradiation for 300 h. The degradation rate can be controlled by changing the content of TiO2 nanoparticles in PE plastic. The degradation of composite plastic initiated on PE-TiO2 interface and then extended into polymer matrix induced by the diffusion of the reactive oxygen species generated on TiO2 particle surface. The present study demonstrates that the polymer-TiO2 compositing is a practical and promising way to degrade the plastic waste under solar light without any pollution. (c) 2007 Elsevier B.V. All rights reserved.