Esfahani Heidar Javdani, Shahhosseini Shahrokh, Ghaemi Ahad
School of Chemical, Petroleum and Gas Engineering, Iran University of Science and Technology, Tehran, Iran.
Sci Rep. 2023 Oct 17;13(1):17700. doi: 10.1038/s41598-023-44076-9.
Modified mesoporous NH-Zr-BTC mixed ligand MOF nanocomposites were synthesized via the hydrothermal method as a novel adsorbent for CO capture. The newly modified MOF-808 with NH demonstrated a similar mesoporous morphology as MOF-808, whereas the specific surface area, pore volume, and average particle size, respectively, increased by 15%, 6%, and 46% compared to those of MOF-808. The characterization analyses exhibited the formation of more active groups on the adsorbent surface after modification. In addition, a laboratory adsorption setup was used to evaluate the effect of temperature, pressure, and NH content on the CO adsorption capacity in the range of 25-65 °C, 1-9 bar, and 0-20 wt%, respectively. An increase in pressure and a decrease in temperature enhanced the adsorption capacity. The highest equilibrium adsorption capacity of 369.11 mg/g was achieved at 25 °C, 9 bar, and 20 wt% NH. By adding 20 wt% NH, the maximum adsorption capacity calculated by the Langmuir model increased by about 4% compared to that of pure MOF-808. Moreover, Ritchie second-order and Sips models were the best-fitted models to predict the kinetics and isotherm data of CO adsorption capacity with the high correlation coefficient (R > 0.99) and AARE% of less than 0.1. The ΔH°, ΔS°, and ΔG° values were - 17.360 kJ/mol, - 0.028 kJ/mol K, and - 8.975 kJ/mol, respectively, demonstrating a spontaneous, exothermic, and physical adsorption process. Furthermore, the capacity of MH-20% sample decreased from 279.05 to 257.56 mg/g after 15 cycles, verifying excellent stability of the prepared mix-ligand MOF sorbent.
通过水热法合成了改性介孔NH-Zr-BTC混合配体金属有机框架（MOF）纳米复合材料，作为一种用于捕获CO的新型吸附剂。新的用NH改性的MOF-808与MOF-808具有相似的介孔形态，而其比表面积、孔体积和平均粒径相比MOF-808分别增加了15%、6%和46%。表征分析表明改性后吸附剂表面形成了更多活性基团。此外，使用实验室吸附装置分别在25-65°C、1-9 bar和0-20 wt%的范围内评估温度、压力和NH含量对CO吸附容量的影响。压力增加和温度降低会提高吸附容量。在25°C、9 bar和20 wt% NH条件下实现了最高平衡吸附容量369.11 mg/g。通过添加20 wt% NH，由Langmuir模型计算的最大吸附容量相比纯MOF-808增加了约4%。此外，Ritchie二级模型和Sips模型是预测CO吸附容量动力学和等温线数据的最佳拟合模型，相关系数（R>0.99）且平均绝对相对误差百分比（AARE%）小于0.1。ΔH°、ΔS°和ΔG°值分别为-17.360 kJ/mol、-0.028 kJ/mol K和-8.975 kJ/mol，表明这是一个自发、放热的物理吸附过程。此外，MH-20%样品在15次循环后容量从279.05 mg/g降至257.56 mg/g，验证了所制备的混合配体MOF吸附剂具有出色的稳定性。
