State Key Joint Laboratory of Environmental Simulation and Pollution Control, Research Center for Eco-Environmental Sciences , Chinese Academy of Sciences , Beijing 100085 , China.
University of Chinese Academy of Sciences , Beijing 100049 , China.
Environ Sci Technol. 2019 Sep 17;53(18):10855-10862. doi: 10.1021/acs.est.9b00941. Epub 2019 Aug 28.
Adsorption is an efficient method for atmospheric NO abatement under ambient conditions; however, traditional adsorbents suffer from limited adsorption capacity and byproduct formation. Developing a low-cost material with high capacity for atmospheric NO elimination remains a challenge. Here, we synthesized a nanodispersed MnO/γ-AlO (Mn/Al) material that exhibits excellent ability to remove NO. The 10 wt % Mn/Al sample showed the highest removal capacity, with 247.6 mg/g, which is superior to that of activated carbon (42.6 mg/g). There were no byproducts produced when Mn/Al was tested with ppb-level NO. The NO abatement mechanism with Mn/Al is different from physisorption or chemisorption. NO removal is mainly a catalytic process in air, during which surface hydroxyls and lattice oxygen are involved in the oxidation of NO to nitrate. In contrast, a chemical reaction between Mn and NO is dominant in N, where Mn is converted into Mn and NO is reduced to nitrite. Washing with deionized water is an effective and convenient method for the regeneration of saturated Mn/Al, and an 86% adsorption capacity was recovered after one washing. The results suggest that this low-cost Mn/Al material with easy preparation and regeneration is a promising candidate material for atmospheric NO elimination.
吸附法是一种在环境条件下有效去除大气 NO 的方法；然而，传统的吸附剂存在吸附容量有限和副产物生成的问题。开发一种具有高容量的低成本材料来去除大气中的 NO 仍然是一个挑战。在这里，我们合成了一种纳米分散的 MnO/γ-Al2O3（Mn/Al）材料，该材料具有优异的去除 NO 的能力。10wt%Mn/Al 样品表现出最高的去除容量，为 247.6mg/g，优于活性炭（42.6mg/g）。当用 Mn/Al 测试 ppb 级别的 NO 时，没有生成副产物。Mn/Al 的 NO 去除机制不同于物理吸附或化学吸附。NO 的去除主要是在空气中的催化过程，在此过程中，表面羟基和晶格氧参与了 NO 向硝酸盐的氧化。相比之下，在 N 中，Mn 和 NO 之间的化学反应占主导地位，其中 Mn 转化为 Mn，NO 还原为亚硝酸盐。用去离子水洗涤是一种有效且方便的方法，可以使饱和的 Mn/Al 再生，经过一次洗涤后，吸附容量恢复了 86%。结果表明，这种低成本、易于制备和再生的 Mn/Al 材料是一种很有前途的大气 NO 去除候选材料。
