State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China.
Environ Sci Pollut Res Int. 2020 May;27(15):18329-18344. doi: 10.1007/s11356-020-08042-6. Epub 2020 Mar 17.
Simultaneous removal of NOx and SO is carried out by an oxidation-absorption process, which NO oxidized by active hydroxyl radicals (·OH) derived from catalytic decomposition of vaporized HO over FeO/TiO and then adsorbed by NaOH solution along with SO. FeO/TiO synthesized by wet impregnation method with an additional reduction under H atmosphere was characterized by XRD, FTIR, BET, XPS, and VSM analysis. Effects of HO concentration, HO injection rate, reaction temperature, gas flow rate, and flue gas component on simultaneous removal were investigated. The experimental results show that NO can be effectively oxidized by highly reactive ·OH radicals generated from HO decomposition over FeO/TiO catalyst, and removal efficiencies of 93.31% for NO, 85.90% for NOx, and 100% for SO were obtained. The surface zero-valent iron (Fe) and divalent iron (Fe) are the key factors of the catalytic oxidation with hydroxyl radical. HO adsorption and dissociation mechanism on catalyst surface was studied using DFT calculation. The calculation results demonstrate that HO prefers to dissociate on iron containing surface, and ·OH radicals generation follow by Haber-Weiss (H-W) mechanism. The stable oxidative product of HNO and HNO were generated through NO/NO and HO co-adsorption on the FeO/TiO (0 0 1) surface.
同时去除 NOx 和 SO 是通过氧化吸收过程实现的，其中 NO 被源自蒸汽态 HO 在 FeO/TiO 上催化分解产生的活性羟基自由基（·OH）氧化，然后与 SO 一起被 NaOH 溶液吸附。采用水蒸气还原法合成的 FeO/TiO 用 XRD、FTIR、BET、XPS 和 VSM 分析进行了表征。考察了 HO 浓度、HO 注入速率、反应温度、气体流速和烟气成分对同时去除的影响。实验结果表明，HO 在 FeO/TiO 催化剂上分解产生的高反应性·OH 自由基可有效氧化 NO，NO 的去除率为 93.31%，NOx 的去除率为 85.90%，SO 的去除率为 100%。表面零价铁（Fe）和二价铁（Fe）是催化氧化与羟基自由基的关键因素。采用密度泛函理论（DFT）计算研究了 HO 在催化剂表面的吸附和解离机制。计算结果表明，HO 优先在含铁表面上解离，·OH 自由基的生成遵循 Haber-Weiss（H-W）机制。通过 NO/NO 和 HO 在 FeO/TiO（001）表面的共吸附，生成了 HNO 和 HNO 的稳定氧化产物。
