Fe3+掺杂TiO2光催化降解聚乙烯薄膜的研究

以快速溶胶-凝胶法制备了纳米TiO₂光催化剂，并用Fe³⁺对其掺杂改性，在室温条件下, 用于固相光催化降解聚乙烯(PE)包装薄膜的研究. 对催化剂和薄膜进行了X衍射分析(XRD)、傅立叶红外光谱分析(FT-IR)、扫描电子显微镜(SEM)形貌观察. 结果表明， 60 W紫外光辐射240 h后， PE失重为8.43%, 锐钛矿型纳米TiO₂光催化剂使PE失重30.66%；用Fe³⁺掺杂后，0.5%Fe₂O3/TiO₂、1.0%Fe₂O₃/TiO₂和2.0%Fe₂O3/TiO₂分别使PE失重35.91%、20.72%和13.30%. 光催化剂加速了PE的失重，碳链的断裂和光氧化腐蚀，在薄膜表面形成大量的坑洞，降解产物中的小分子量的石蜡含量明显增高. Fe³⁺掺杂有一个最佳量， 0.5%Fe₂O3/TiO₂光催化降解PE的活性最高.

Degradation of Polyethylene Film by Fe3+/TiO2 Photocatalyst

Nano-sized TiO₂ doped with different percentage of Fe³⁺was prepared quickly by sol-gel process and was first used as photocatalyst to degrade polyethylene(PE) film under UV (intensity of 60 W) irradiation for 240 h in the ambient air. Some properties of photocatalysts and PE films were characterized by the means of XRD, FT-IR and SEM. The results claimed that PE lost only 8.43%(w) of its mass under UV irradiation for 240 h, anatase TiO₂ made PE film lost 30.66%(w). 0.5% Fe₂O₃/TiO₂, 1.0%Fe₂O₃/TiO₂ and 2.0% Fe₂O₃/TiO₂ made PE lost their weights 35.91%(w), 20.72%(w), and 13.30%(w), respectively. Photocatalysts speeded the PE macromolecular chains scission and photo oxidation. SEM morphology of PE film after photodegradation showed that there were numerous pits and holes in the film. The XRD patterns indicated that products contained more wax in PE film than that in PE film without photocatalysts. There was an optimal content of doping Fe³⁺ in anatase TiO₂. 0.5%Fe₂O₃/TiO₂ had a higher activity in photdegradation of PE film than other TiO₂ photocatalysts.