采用巨正则系综蒙特卡罗(GCMC)模拟方法,对二氧化碳在5种具有相同拓扑结构的金属-有机骨架材料(IRMOFs),即IRMOF-1,-8,-10,-14,-16中吸附产生的阶梯现象进行了详细的研究.结果表明:低温条件下,孔径越大的IRMOFs越容易发生阶梯现象;发生阶梯现象的转变压力与能够发生阶梯现象的转变温度都与孔径呈线性关系.此外,模拟结果进一步验证了二氧化碳分子之间的静电作用力是阶梯现象发生的关键因素.这些规律将为金属-有机骨架材料(MOFs)的设计和改性以及二氧化碳在混合气体中的吸附分离提供有用的信息.
Grand canonical Monte Carlo (GCMC) simulations were performed to study the stepped behaviors of carbon dioxide adsorption in the following five isoreticular metal-organic frameworks (IRMOFs):IRMOF-1,-8,-10,-14,-16.The simulation results show that the stepped phenomenon occurs easily when the temperature is low and the pore size is large for these IRMOFs.The critical pressure and temperature where the stepped behavior occurs show a linear relationship with the pore size.The results also further indicate that the electrostatic interaction between CO2 and CO2 molecules plays a dominant role on the stepped behavior.All these findings may provide useful information for the design and modification of MOFs for the adsorption and separation of carbon dioxide in gas mixtures.