Rabbani Mohammad G, Sasse Riley K, Behera Swayamprabha, Jena Puru, Liu Jian, Thallapally Praveen K, Islamoglu Timur, Shehab Mohammad K, Kaid Mahmoud M, Farha Omar K, El-Kaderi Hani M
Department of Chemistry, University of Wisconsin-Platteville, Platteville, Wisconsin 53818, United States.
Department of Chemistry, Pennsylvania State University, University Park, Pennsylvania 16802, United States.
Langmuir. 2024 Apr 16;40(15):8024-8034. doi: 10.1021/acs.langmuir.3c03980. Epub 2024 Apr 4.
Sulfur dioxide (SO) is a harmful acidic gas generated from power plants and fossil fuel combustion and represents a significant health risk and threat to the environment. Benzimidazole-linked polymers (BILPs) have emerged as a promising class of porous solid adsorbents for toxic gases because of their chemical and thermal stability as well as the chemical nature of the imidazole moiety. The performance of BILPs in SO capture was examined by synergistic experimental and theoretical studies. BILPs exhibit a significantly high SO uptake of up to 8.5 mmol g at 298 K and 1.0 bar. The density functional theory (DFT) calculations predict that this high SO uptake is due to the dipole-dipole interactions between SO and the functionalized polymer frames through OS(δ)···N(δ)-imine and O═S═O(δ)···H(δ)-aryl and intermolecular attraction between SO molecules (O═S═O(δ)···S(δ)O). Moderate isosteric heats of adsorption ( ≈ 38 kJ mol) obtained from experimental SO uptake studies are well supported by the DFT calculations (≈40 kJ mol), which suggests physisorption processes enabling rapid adsorbent regeneration for reuse. Repeated adsorption experiments with almost identical SO uptake confirm the easy regeneration and robustness of BILPs. Moreover, BILPs possess very high SO adsorption selectivity at low concentration over carbon dioxide (CO), methane (CH), and nitrogen (N): SO/CO, 19-24; SO/CH, 118-113; SO/N, 600-674. This study highlights the potential of BILPs in the desulfurization of flue gas or other gas mixtures through capturing trace levels of SO.
二氧化硫（SO₂）是一种由发电厂和化石燃料燃烧产生的有害酸性气体，对健康构成重大风险并威胁环境。苯并咪唑连接聚合物（BILPs）因其化学和热稳定性以及咪唑部分的化学性质，已成为一类有前景的有毒气体多孔固体吸附剂。通过协同的实验和理论研究考察了BILPs对SO₂的捕获性能。BILPs在298 K和1.0 bar下表现出高达8.5 mmol g⁻¹的显著高SO₂吸附量。密度泛函理论（DFT）计算预测，这种高SO₂吸附量是由于SO₂与功能化聚合物骨架之间通过O═S(δ)···N(δ)-亚胺和O═S═O(δ)···H(δ)-芳基的偶极-偶极相互作用以及SO₂分子之间的分子间吸引力（O═S═O(δ)···S(δ)O）。从实验SO₂吸附研究中获得的适度吸附等温热（≈38 kJ mol⁻¹）得到了DFT计算（≈40 kJ mol⁻¹）的有力支持，这表明物理吸附过程能够实现吸附剂的快速再生以供重复使用。几乎相同的SO₂吸附量的重复吸附实验证实了BILPs易于再生且具有稳定性。此外，BILPs在低浓度下对二氧化硫的吸附选择性远高于二氧化碳（CO₂）、甲烷（CH₄）和氮气（N₂）：SO₂/CO₂，19 - 24；SO₂/CH₄，118 - 113；SO₂/N₂，600 - 674。这项研究突出了BILPs通过捕获痕量SO₂对烟道气或其他气体混合物进行脱硫的潜力。
