College of Chemistry & Chemical Engineering, Qingdao University, Qingdao, 266071, China.
State Key Laboratory Base of Eco-chemical Engineering, Qingdao University of Science and Technology, Qingdao 266042, China.
Environ Res. 2022 Oct;213:113637. doi: 10.1016/j.envres.2022.113637. Epub 2022 Jun 7.
Power plants emit sulfur dioxide (SO) during combustion, which is typically removed via wet flue gas desulfurization, but this process produces numerous secondary pollutants. Ionic liquids (ILs) can potentially be used to remove SO, but they suffer from poor mass transfer rates. Hydroxyl ammonium ILs are classical cheap ILs that contain electron-rich O and N sites that favor high absorption capacities. To accelerate mass transfer, two hydroxyl ammonium ILs, triethanolamine citrate and triethanolamine lactate, were immobilized on activated carbon (SILs) and used to capture SO from simulated flue gas. They exhibited excellent adsorption at low SO partial pressures due to the presence of a large gas-liquid interface. The molar adsorption ratios reached 7.65 and 2.40 mol/mol at 10 kPa SO. The SILs possessed good SO selectivity in SO/CO and SO/O mixtures, because of the only 8% reduction in the total adsorption of SILs at 60 °C. And they exhibited excellent reversibility in which their total adsorption capacities were unaffected after 5 adsorption-desorption cycles. The mechanism analysis revealed that chemical adsorption was the major adsorption route, although physical adsorption also occurred. The main reactive sites included C-O and N-H groups in the ionic liquid. These SILs may potentially replace traditional chemical absorption materials for the separation of SO from flue gas.
发电厂在燃烧过程中会排放二氧化硫（SO），通常通过湿法烟气脱硫来去除，但该过程会产生大量的二次污染物。离子液体（ILs）可用于去除 SO，但它们的传质速率较差。羟铵离子液体是经典的廉价 ILs，其中含有富电子的 O 和 N 位点，有利于高吸收容量。为了加速传质，将两种羟铵离子液体，柠檬酸三乙醇胺和乳酸三乙醇胺，固定在活性炭（SILs）上，用于从模拟烟道气中捕获 SO。由于存在大的气液界面，它们在低 SO 分压下表现出优异的吸附性能。在 10 kPa SO 下，摩尔吸附比达到 7.65 和 2.40 mol/mol。SILs 在 SO/CO 和 SO/O 混合物中具有良好的 SO 选择性，因为在 60°C 时 SILs 的总吸附量仅降低了 8%。它们表现出良好的可恢复性，在 5 次吸附-解吸循环后，其总吸附容量没有受到影响。机理分析表明，化学吸附是主要的吸附途径，尽管也存在物理吸附。主要的反应性位点包括离子液体中的 C-O 和 N-H 基团。这些 SILs 可能有潜力替代传统的化学吸收材料，用于从烟道气中分离 SO。
