College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan, 410082, PR China.
College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan, 410082, PR China.
Chemosphere. 2020 Oct;256:127083. doi: 10.1016/j.chemosphere.2020.127083. Epub 2020 May 16.
Catalytic reduction of toxic and aqueous stable nitrophenols by gold nanoparticles (Au NPs) is hot issue due to the serious environmental pollution in recent years. But the expensive price and poor recycling performance of Au NPs limit its further application. Defect-free high silica zeolite is suitable support for Au NPs due to its cheaper price, higher stability and stronger adsorbability, but the low alumina content and defect sites usually lead to poor Au NPs loading efficiency. Herein, we reported the improved Au NPs loading efficiency on defect-free high silica ZSM-5 zeolite through the additional surface fluffy structure. The fluffy structure was created through the addition of multi-walled carbon nanotubes (MWCNTs) and ethanol into synthesis gel. Highly dispersed ca. 4 nm Au NPs on zeolite surface are prepared by the green enhanced sol-gel immobilization method. The Au NPs loading efficiency on conventional ZSM-5 zeolite is 10.7%, in contrast, this result can arrive to 82.6% on fluffy structure ZSM-5 zeolite. The fluffy structure ZSM-5 zeolite and Au NPs nanocomposites show higher efficiency than traditional Au/ZSM-5 nanocomposites towards catalytic reduction of nitrophenols. Additionally, the experiments with different affecting factors (MWCNTs dosage, aging time, catalysts dosage, pH, initial 4-NP concentration, storage time and recycling times) were carried out to test general applicability of the nanocomposites. And the degradation of nitrophenols experiment was operated to explore the catalytic performance of the prepared nanocomposites in further environmental application. The detailed possible relationship between zeolite with fluffy structure and Au NPs is also proposed in the paper.
由于近年来严重的环境污染，金纳米粒子（Au NPs）催化还原有毒和稳定的水相硝酚类化合物是一个热门话题。但是，Au NPs 的昂贵价格和较差的回收性能限制了其进一步的应用。无缺陷的高硅沸石由于其价格较低、稳定性较高和吸附性较强，是 Au NPs 的合适载体，但低氧化铝含量和缺陷位通常导致 Au NPs 的负载效率较差。在此，我们通过额外的表面蓬松结构，报道了无缺陷的高硅 ZSM-5 沸石上 Au NPs 负载效率的提高。蓬松结构是通过在合成凝胶中添加多壁碳纳米管（MWCNTs）和乙醇来制备的。通过绿色增强溶胶-凝胶固定化法制备了高度分散的约 4nm Au NPs 在沸石表面上。在常规 ZSM-5 沸石上的 Au NPs 负载效率为 10.7%，相比之下，在蓬松结构 ZSM-5 沸石上的负载效率可以达到 82.6%。蓬松结构 ZSM-5 沸石和 Au NPs 纳米复合材料在催化还原硝酚类化合物方面表现出比传统 Au/ZSM-5 纳米复合材料更高的效率。此外，还进行了不同影响因素（MWCNTs 用量、陈化时间、催化剂用量、pH 值、初始 4-NP 浓度、储存时间和回收次数）的实验，以测试纳米复合材料的通用性。并进行了降解硝酚实验，以进一步探索制备的纳米复合材料在环境应用中的催化性能。本文还提出了沸石与蓬松结构之间可能存在的详细关系。
