环糊精修饰的过渡金属氧化物纳米材料与选择性催化降解氯酚类污染物

Chlorophenols (CPs), as a representative of typical organic micropollutants, could be a serious threat to human health and ecological environmental system. Owing to the interference of natural organic matters in the environment and short reactive path length of hydroxyl radicals (< 2 nm), the radical oxidation of organic micropollutants catalyzed by nanomaterials generally showed a low degradation efficiency to organic micropollutans. In order to achieve efficient degradation of chlorophenol organic micropollutants, this project will aim to obtain transition metal oxides@cyclodextrin nanocomposites with improved efficiency of radical utilization and anti-interference ability, benefiting from the host-guest interactions of cyclodextrins to chlorophenols and their modification ability to transition metal oxide nanomaterials. Enzyme-like catalysts are expected to be synergistically associated with selective adsorption and catalytic degradation. The formation of nanocomposites and the molecular degradation pathways of pollutants could be examined by means of X-ray Photoelectron Spectroscopy, Nuclear Magnetic Resonance, Gas Chromatographic-Mass Spectrometry, Electron Spin Resonance, Raman spectroscopy, theoretical calculations and so on. The role of host-guest interactions from cyclodextrins on selective catalytic degradation could be further disclosed. The key strategy is to simultaneously achieve the stable modification of cyclodextrin and the affinity of cyclodextrin cavity to the catalytic active sites on the surface of nanomaterials, realizing synergistic effect of selective adsorption to pollutants and radical generation on the surface of nanomaterials.

氯酚（CPs）作为典型的有机微污染物代表之一，可对人类健康和生态环境系统产生严重威胁。由于易受环境中常见有机质等物质的干扰以及羟基自由基的有效进攻自由程较短（在2nm范围内），纳米材料催化生成自由基氧化这类污染物的降解效率通常比较低。为了实现对氯酚类有机微污染物的高效治理，本项目利用环糊精（CD）与氯酚分子的主客体相互作用以及对过渡金属氧化物(TMO)纳米材料的可修饰特性，合成TMO@CD纳米复合材料,提高自由基氧化效率与抗环境干扰能力，构建出具有选择性吸附与催化降解协同统一的类酶催化剂。借助XPS、NMR、GC-MS、ESR、Raman等检测手段与理论计算分析，研究材料的形成和污染物的降解分子机制，认识环糊精的主客体作用在选择性催化降解中的作用。本项目的关键是实现环糊精的稳定修饰并确保环糊精空腔接近纳米材料表面的催化活性中心，以实现选择性吸附与催化自由基形成在纳米材料表面的协调统一。

在本项目中，我们将环糊精的分子识别选择性吸附和过渡金属氧化物纳米材料的类Fenton催化有机地融合，在宽pH范围以及中性环境中，发展了一类选择性吸附与催化降解协调统一的纳米复合材料，实现对酚类污染物的识别选择性高效降解，同时通过实验表征和理论计算进一步明晰了环糊精与污染物之间的主客体作用在催化降解的分子机制。我们所做的主要工作包括：<1> 过渡金属氧化物@环糊精复合纳米材料的制备策略研究；<2> 环糊精在过渡金属氧化物表面的结合构型研究；<3>环糊精与污染物分子的作用机制；<4>过渡金属氧化物@环糊精复合体系类Fenton降解酚类污染物研究；<5> 类Fenton降解酚类污染物机制研究。通过本项目的一系列工作，基本建立了过渡金属氧化物@环糊精复合纳米材料选择性吸附与催化降解有机统一的一体化治理方法，为复杂水质的有机污染物治理提供指导意见。