双功能纳米零价铁催化剂的可控合成及其对水中低浓度氯代有机污染物的富集性降解研究

Currently, nanoscaled metallic Fe-based catalytic degradation is a promising technique for the practical treatment of chlorinated organic pollutants (COPs) contaminated aqueous solutions. Normally, the concentration of COPs is quite low in aqueous solutions, which gives rise to the problem of slow mass transfer. Moreover, the conventional nanoscaled metallic Fe catalysts usually suffer from migration-induced aggregation and oxidation of Fe nanoparticles, frequently showing poor cycling performance. To address these issues, a novel bifunctional nanoscaled metallic Fe catalyst will be developed by using vegetable tannin, an amphiphilic natural polyphenol, as the starting material that is treated by phenol-formaldehyde condensation, hydrophobic grafting and immobilization of metallic Fe nanoparticles. The as-prepared bifunctional catalyst is able to simultaneously enrich and degrade the COPs in aqueous solutions, thus showing highly efficient degradation to the COPs at low concentration in aqueous solutions. The main contents investigated in this project include: (1) Synthesis of hierarchically porous phenolic resin matrix and adjustment to its pore structure; (2) Influences of different grafting hydrophobic groups on the hydrophobic properties of hierarchically porous phenolic resin matrix; (3) Immobilization of metallic Fe nanoparticles and adjustment to their morphology; (4) Influences of pore structure, hydrophobicity, morphology and composition of Fe nanoparticles on the catalyst activity, as well as the dependent relationship between the catalyst structure and the catalytic performance. In summary, the implementation of the present project is promising to provide new approach for the treatment of aqueous solutions contaminated by COPs at low concentration, and also help to explore new resource utilization of tannin with high additive values.

纳米零价铁（FeNPs）催化降解技术是目前有实用前景的水中氯代有机污染物（COPs）治理技术。然而，水中COPs的浓度较低，易导致传质速率慢，催化降解效率低。此外，以往的FeNPs催化剂还存在FeNPs易迁移、团聚和氧化等问题，重复使用性亟待提高。为解决上述问题，拟以植物单宁这类两亲性天然多酚为基础材料，通过酚醛缩合、疏水性接枝及FeNPs负载，制备兼具富集和催化降解功能的双功能负载型FeNPs催化剂，从而实现对水中低浓度COPs的高效降解。项目的主要研究内容包括：（1）多级孔结构酚醛树脂载体的制备及其孔结构的调控；（2）不同疏水基接枝对多级孔结构酚醛树脂疏水性的影响；（3）FeNPs的负载及其形貌调控；（4）孔结构、疏水性、FeNPs形貌和组成等对催化性能的影响，催化剂性能与其结构之间的构效关系。项目的实施可为水中低浓度COPs的去除提供新方法，也为单宁的高附加值资源化利用提供新思路。

纳米零价铁（FeNPs）催化降解技术是目前有实用前景的水中氯代有机污染物（COPs）治理技术。然而，水中COPs的浓度较低，易导致传质速率慢，催化降解效率低。此外，以往的Fe NPs催化剂还存在FeNPs易迁移、团聚和氧化等问题，重复使用性亟待提高。为解决上述问题，本项目利用植物单宁这类两亲性天然多酚为基础材料，设计制备了一系列兼具富集和催化降解功能的双功能负载型FeNPs催化剂，从而实现对水中低浓度COPs的高效降解。项目的主要研究内容包括：（1）单宁多孔酚醛树脂的制备及其孔结构的调控。以典型的缩合类单宁杨梅单宁为原材料，通过羟醛缩合反应制备了多孔单宁树脂。此外在此基础上，利用杨梅单宁对具有多孔结构的密胺泡沫、PU泡沫等进行修饰，制备了单宁修饰的多孔泡沫材料；（2）系统研究了单宁多孔酚醛树脂以及单宁修饰多孔泡沫对典型COPs的吸附性能。基于单宁的两亲性，这几类材料对水中二氯苯酚等COPs表现出了良好的吸附性能，对低浓度的COPs具有良好的富集效果；（3）以单宁多孔酚醛树脂以及单宁修饰多孔泡沫为载体，利用单宁大量的邻位酚羟基对金属离子的强螯合作用，负载Fe离子后经过化学还原，制备了一系列FeNPs催化剂，FeNPs分散度好且在反应过程中没有发生明显的团聚和流失；（4）研究了上述催化材料对水中典型COPs的催化降解性能，材料对二氯苯酚等COPs表现出了高吸附降解效率，去除率可以达到90%以上，且可以通过简单的再生实现重复使用。.项目的实施可为水中低浓度COPs的去除提供新方法，也为单宁的高附加值资源化利用提供新思路。