Heydari Amirhossein, Khatibi Mahdi, Ashrafizadeh Seyed Nezameddin
Research Lab for Advanced Separation Processes, Department of Chemical Engineering, Iran University of Science and Technology, Narmak, Tehran 16846-13114, Iran.
Phys Chem Chem Phys. 2023 Oct 11;25(39):26716-26736. doi: 10.1039/d3cp03768a.
This research explores ion transport behavior and functionality in a hybrid nanochannel that consists of two conical and cylindrical parts. The numerical investigation focuses on analyzing the length of each part in the nanochannel. The nanochannels are hybrid cavities embedded in a membrane, where the size of the conical part varies as equal to, larger than, or smaller than the cylindrical part. The nanochannel is coated with a polyelectrolyte layer that exhibits a dense charge density distribution. The charge density of the soft layer is described using the soft step distribution function. We study the electroosmotic flow, ionic current, rectification, and selectivity of the nanochannel bulk electrolyte concentration, the charge density of the polyelectrolyte layer, and decay length, while considering the effect of ionic partitioning. The steady-state Poisson-Nernst-Planck and Navier-Stokes equations are solved using the finite element method. The findings reveal that the nanochannel with a more extensive conical section demonstrates increased rectification, with the rectification factor rising from 1.4 to 2 at a bulk concentration of 100 mM. Additionally, the nanochannel with a longer cylindrical part exhibits improved selectivity under negative voltage conditions, while positive voltage introduces a different situation. The nanochannel with equal cylindrical and conical parts significantly affects conductivity by modifying the charge density in the soft layer, resulting in a 3.125-fold increase in conductivity under positive voltage when the charge density in the polyelectrolyte layer is raised from 25 to 100 mol m. This research focuses on creating intelligent nanochannels by controlling mass concentration, charge density, and collapse length, improving system performance, and optimizing properties. It also offers valuable insights into ion transport mechanisms in nanochannel systems, advancing our understanding in this field.
本研究探讨了由两个锥形和圆柱形部分组成的混合纳米通道中的离子传输行为和功能。数值研究重点分析了纳米通道中每个部分的长度。纳米通道是嵌入膜中的混合腔体，其中锥形部分的尺寸等于、大于或小于圆柱形部分。纳米通道涂有一层聚电解质层，该层呈现出密集的电荷密度分布。使用软阶跃分布函数描述软层的电荷密度。我们研究了纳米通道的电渗流、离子电流、整流和选择性，同时考虑了离子分配的影响，涉及本体电解质浓度、聚电解质层的电荷密度和衰减长度。使用有限元方法求解稳态泊松 - 能斯特 - 普朗克方程和纳维 - 斯托克斯方程。研究结果表明，具有更宽锥形部分的纳米通道表现出更高的整流性，在本体浓度为100 mM时，整流因子从1.4增加到2。此外，具有较长圆柱形部分的纳米通道在负电压条件下表现出更好的选择性，而正电压则带来不同的情况。圆柱形和锥形部分相等的纳米通道通过改变软层中的电荷密度对电导率有显著影响，当聚电解质层中的电荷密度从25 mol/m提高到100 mol/m时，在正电压下电导率增加3.125倍。本研究致力于通过控制质量浓度、电荷密度和崩塌长度来创建智能纳米通道，提高系统性能并优化性能。它还为纳米通道系统中的离子传输机制提供了有价值的见解，推动了我们在该领域的理解。
