燃煤烟气中As2O3在铁基吸附剂表面的预氧化-吸附反应机理

Arsenic is one of the trace toxic pollutants emitted from coal-fired power stations. The study on arsenic control in flue gas is of great significance to the environmental protection and SCR system efficiency improvement. As a promising sorbent for arsenic removal, iron-based sorbent not only meets the requirement of adsorption efficiency and operating temperature, but also reduces the toxicity and mobility of adsorbed arsenic. However, inadequate acknowledge of the mechanism of arsenic adsorption by iron-based sorbent restricts its application and implementation to a certain degree. Starting with the correlation between arsenic oxidation and its adsorption, this project investigates the mechanism of catalytic oxidation of iron-based sorbents on arsenic adsorption firstly. On that basis, the regulatory mechanism of pre-oxidation effect on arsenic adsorption under complex flue gas conditions is studied. Lastly, the reaction paths of oxidation/peroxidation-adsorption between arsenic and iron-based sorbent are established with the help of quantum chemistry theory. The project is expected for a breakthrough on the decoupling of arsenic oxidation and its adsorption. The results of this study will provide theoretical support on arsenic adsorption on iron-based sorbents and also provide theoretical basis for the development and application of high efficiency arsenic adsorbent.

砷是燃煤电站排放的有害痕量元素污染物之一，开展烟气砷控制对生态环境保护和SCR脱硝系统增效降耗具有重要意义。铁基吸附剂在满足工作温度要求和吸附效率要求的同时，可大大降低吸附后砷的毒性和环境迁移性，是一种值得探索的气相砷吸附剂。目前对铁基吸附剂气相砷吸附机理的认知尚存不足，这在一定程度上制约了烟气脱砷技术的发展。项目以气相砷氧化与吸附之间的关联机制为切入点，首先探明铁基吸附剂的催化氧化作用对As2O3吸附的影响机理；在此理论基础上，以吸附氧生成规律为媒介，研究复杂烟气组分下预氧化作用对As2O3吸附的调控机制；最后借助量子化学理论，构建气相砷在铁基吸附剂表面的氧化/预氧化-吸附反应路径。项目预期在气相砷吸附的氧化和固定步骤解耦方面实现突破，在气相砷氧化与吸附的动态机制建立方面取得创新性成果，为铁基吸附剂吸附气相砷提供进一步的理论支撑，为高效气相砷吸附剂的开发与应用提供理论依据。

砷是燃煤电站排放的有害痕量元素污染物之一，开展烟气砷控制对生态环境保护和SCR脱硝系统增效降耗具有重要意义。铁基吸附剂在满足工作温度要求和吸附效率要求的同时，可大大降低吸附后砷的毒性和环境迁移性，是一种值得探索的气相砷吸附剂。目前对铁基吸附剂气相砷吸附机理的认知尚存不足，这在一定程度上制约了烟气脱砷技术的发展。项目以气相砷氧化与吸附之间的关联机制为切入点，首先探明铁基吸附剂的催化氧化作用对As2O3吸附的影响机理；在此理论基础上，以吸附氧生成规律为媒介，研究复杂烟气组分下预氧化作用对As2O3吸附的调控机制；最后借助量子化学理论，构建气相砷在铁基吸附剂表面的氧化/预氧化-吸附反应路径。