Zhang Zhen, Li Zikuo, Feng Youxiang, Yu Jingxiang, Zhang Xikai, Wen Jinchao, Nie Haotian, Yu Yue, Jia Li
College of Electrical and Power Engineering, Taiyuan University of Technology, Taiyuan 030024, China.
College of Economics and Management, Taiyuan University of Technology, Taiyuan 030024, China.
Polymers (Basel). 2024 Sep 3;16(17):2508. doi: 10.3390/polym16172508.
To reduce the mercury content in flue gas from coal-fired power plants and to obtain high-performance, low-cost mercury adsorbents, a novel composite material was prepared by structural design through the in situ growth method. Functionalization treatments such as the modification of functional groups and multilayer loading of polymetallic were conducted. These materials include the MOF material UiO-66 and modified biochar doped with Fe/Ce polymetallic, both of which contain unsaturated metal centrals and oxygen-containing functional groups. On the basis of obtaining the effects of adsorption temperature and composite ratio on the Hg removal characteristics, coupling and synergistic mechanisms between the various types of active centers included were investigated by using a variety of characterization and analysis tools. The active adsorption sites and oxidation sites were identified during this process, and the constitutive relationship between the physicochemical properties and the performance of Hg removal was established. The temperature-programmed desorption technique, Grand Canonical Monte Carlo simulation, and adsorption kinetic model were employed to reveal the mechanism of Hg removal. The results showed that the UiO-66-Br@MBC composite adsorbent possessed an excellent Hg removal performance at adsorption temperatures ranging from 50 to 250 °C, and targeted construction of adsorption and oxidation sites while maintaining thermal stability. The Hg removal by the composites is the result of both adsorption and oxidation. The micropores and small pore mesopores in the samples provide physical adsorption sites. The modified biochar acts as a carrier to facilitate the full exposure of the central metal zirconium ions, the formation of more active sites, and the process of electron transfer. The doping modification of the Br element can enhance the overall redox ability of the sample, and the introduced Fe and Ce polymetallic ions can work in concert to promote the oxidation process of Hg. The excellent regulation of the ratio between adsorption and oxidation sites on the surface of the composite material finally led to a significant boost in the samples' capacity to remove Hg.
为降低燃煤电厂烟气中的汞含量并获得高性能、低成本的汞吸附剂，通过原位生长法进行结构设计制备了一种新型复合材料。进行了诸如官能团改性和多金属多层负载等功能化处理。这些材料包括MOF材料UiO - 66和掺杂Fe/Ce多金属的改性生物炭，二者均含有不饱和金属中心和含氧官能团。在获得吸附温度和复合比例对汞去除特性影响的基础上，利用多种表征和分析工具研究了其中所含各类活性中心之间的耦合和协同机制。在此过程中确定了活性吸附位点和氧化位点，并建立了物理化学性质与汞去除性能之间的本构关系。采用程序升温脱附技术、巨正则蒙特卡罗模拟和吸附动力学模型揭示汞去除机理。结果表明，UiO - 66 - Br@MBC复合吸附剂在50至250℃的吸附温度范围内具有优异的汞去除性能，在保持热稳定性的同时有针对性地构建了吸附和氧化位点。复合材料对汞的去除是吸附和氧化共同作用的结果。样品中的微孔和小孔中孔提供了物理吸附位点。改性生物炭作为载体，促进中心金属锆离子充分暴露，形成更多活性位点以及电子转移过程。Br元素的掺杂改性可增强样品的整体氧化还原能力，引入的Fe和Ce多金属离子协同作用促进汞的氧化过程。复合材料表面吸附和氧化位点比例的优异调控最终显著提高了样品的汞去除能力。
