School of Energy and Power Engineering, Huazhong University of Science & Technology, Luoyu Road 1037, Wuhan, China.
Phys Rev E. 2018 Aug;98(2-1):022406. doi: 10.1103/PhysRevE.98.022406.
Single-file transport of water and other small molecules through narrow pores in osmosis has drawn considerable attention in recent years due to its extensive application in biology and industry. In this work, we propose a discrete model to describe nonideal osmosis through single-file pores. Every site is assumed to be occupied by a molecule according to experiments and simulations. Hence, a dense chain can always be found, and collective hopping is the only movement method enabling the molecular chain to move. The roles of solute in osmosis are clarified in this model. Those molecules reflected at the pore entrance produce osmotic pressure, and those inside the pore contribute to the flow resistance of the molecular chain. The solute molecules that can enter the pore but cannot penetrate it may significantly reduce the osmotic flux, although they are all rejected by the pore. This conclusion can help to clarify the emerging debate about whether the reflection coefficient of the fully rejected solute can be less than 1. The design of highly efficient membrane pores may also benefit from this study.
近年来，由于在生物学和工业中的广泛应用，水和其他小分子通过单分子通道的渗透单分子传输引起了相当大的关注。在这项工作中，我们提出了一个离散模型来描述单分子通道中的非理想渗透。根据实验和模拟，假设每个位置都被一个分子占据。因此，总是可以找到一个密集的链，并且集体跃迁是使分子链移动的唯一运动方式。在这个模型中，澄清了溶质在渗透中的作用。那些在孔口被反射的分子产生渗透压，而那些在孔内的分子则对分子链的流动阻力有贡献。虽然这些溶质分子都被孔所排斥，但那些可以进入孔但不能穿透孔的分子可能会显著降低渗透通量。这一结论有助于澄清关于完全被排斥的溶质的反射系数是否可以小于 1 的新兴争论。高效膜孔的设计也可能受益于这项研究。
