Separation techniques from perspective of weak intermolecular interactions: Theory, characterization and application

As a core component of non-covalent forces, intermolecular weak interactions play a pivotal role in regulating material structural stability and macroscopic properties. In chemical reactions, weak interactions including hydrogen bonds, van der Waals forces, and π−π stacking enable precise control of interaction strength and development of novel separation materials, thereby enhancing conversion efficiency and product selectivity. In recent years, significant advances in infrared spectroscopy, ultraviolet spectroscopy, nuclear magnetic resonance (NMR), and terahertz characterization techniques have substantially deepened our understanding of the dynamic behavior and regulatory mechanisms of weak interactions in complex systems. Infrared spectroscopy facilitates rapid assessment of hydrogen bond formation and strength changes, while ultraviolet spectroscopy directly reflects alterations in electronic environments. NMR spectroscopy enables precise identification of intermolecular interaction mechanisms in localized environments, and terahertz spectroscopy demonstrates unique advantages in detecting dynamic evolution and collective vibrations of weak interactions. These four techniques are widely applied in practice and complement each other. The integration of quantum chemical calculations and molecular simulation methods offers researchers new perspectives. Quantum chemical calculations, grounded in microscopic analysis and enhanced by spectroscopic visualization, synergize with experimental data to reveal interaction mechanisms at the electronic level and accurately predict separation performance, driving separation science from empirical approaches toward rational design. In the field of separation technology, targeted regulation of hydrogen bonding, hydrophobic interactions, van der Waals forces, and π−π stacking has significantly enhanced separation efficiency and selectivity in critical chemical processes such as extraction, adsorption, and membrane separation. This approach demonstrates notable advantages in reducing energy consumption and minimizing by-product formation, providing an effective pathway for developing green and low-carbon separation technologies. However, current separation techniques based on weak intermolecular interactions still face challenges including poor recognition selectivity, low mass transfer rates, and practical production difficulties. Addressing these issues requires fundamental exploration of the nature of weak intermolecular interactions, combined with advanced characterization techniques and interdisciplinary research methods to investigate multi-scale mechanisms and precise control strategies. Therefore, the application of weak intermolecular interactions in separation intermolecular weak interactions will not only help overcome the limitations of conventional separation technologies, but also hold strategic importance for addressing national priorities such as green manufacturing of high-value chemicals and purification of energy-relevant gases under carbon neutrality goals. It is expected that such efforts will propel the field of chemical separation toward greater efficiency, intelligence, and sustainability.