Pentachlorophenol (PCP) is a typical highly-toxic pollutant, and its direct photolysis and conventional photocatalysis may produce more toxic by-products such as dibenzodioxins. It is urgently needed to develop a photocatalytic process able to remove PCP without the generation of highly toxic by-products. To achieve this, enzyme-like molecular-imprinted photocatalysts were prepared by using structural analogues of PCP as pseudo templates. It was found that 2,4-dinitrophenol (DNP) was the best template among the tested analogues. The molecular imprinted polymer (MIP) coated P25 TiO2 photocatalyst DNP–P25 prepared with DNP as the template greatly accelerated the photocatalytic degradation of PCP and depressed the generation of toxic intermediates. It was confirmed that the amino groups at the footprint cavities provided a well-defined micro reaction environment, which made the benzene ring of the adsorbed PCP be better exposed to photo-generated reactive OH radicals, leading to easier cleavage of the benzene ring. Both the intermediate analysis and toxicity evaluation confirmed that the MIP-coated TiO2 can make the photocatalytic degradation a safe and green approach of removing PCP.
五氯苯酚(PCP)是一种典型的高毒性污染物,其直接光解和常规光催化可能会产生更多的有毒副产品,如二苯并二噁英。因此,急需开发一种能够去除PCP而不产生高毒性副产品的光催化过程。为此,通过使用PCP的结构类似物作为伪模板,制备了类似酶的分子印迹光催化剂。研究发现,2,4-
二硝基苯酚(DNP)在测试的类似物中是最优模板。以DNP作为模板制备的分子印迹聚合物(MIP)涂层P25 TiO2光催化剂DNP–P25显著加速了PCP的光催化降解,并抑制了有毒中间体的生成。研究证实,足迹腔内的
氨基提供了一个明确的微反应环境,使得吸附的PCP的苯环更好地暴露于光生成的反应性羟基自由基,从而更易于苯环的断裂。中间体分析和毒性评估均证实,印迹涂层的TiO2能够使光催化降解成为一种安全环保的去除PCP的方法。