Molecular Dynamics Simulation Of Transport Of Lanthanum Chloride Solution In Nanopores

Nanopores are mainly divided into solid nanopores and biological nanopores.The cost of solid-state nanopores is relatively low,and its mechanical properties are more excellent,so it is more advantageous in nanofluidic device design and molecular dynamics simulation of ion transport.In this article,the author focuses on the analysis of the ion transport reaction process in the lanthanum chloride solution.In the mode of MD simulation,the main influencing factors that interfere with the transport of the lanthanum chloride solution in the nanopores are analyzed.The main research contents and conclusions are as follows:The effect of lanthanum chloride solution concentration on solution ion current.For some monovalent and divalent ions,the ion conductivity generally increases with the increase of the solution concentration,and gradually tends to be gentle,while for the lanthanum chloride solution,as the solution concentration continues to increase,the magnitude of the ion current will increase first.After the concentration of the solution reaches a certain level,the current of the solution will reach a peak value and continue to decrease.Effect of Nanopore Wall Charge on Ion Migration in Lanthanum Chloride Solution In nanopores,surface charge always plays an important role in ion transport.The electrostatic interaction between charges is an important remote interaction.In our work,we studied the effect of surface charge on a solution that included trivalent ions(La3 +)transported through a nanopore with a diameter of 3 nm.Using molecular dynamics simulations,we studied the ion migration behavior of electrically driven 1 M lanthanum chloride aqueous solution through positively charged nanopores.In MD,as the concentration increases,the ionic current in the nanopore begins to increase,reaching the maximum value of the ionic current,and then decreases in high solution concentration.In addition,by adjusting the surface charge of the nanopore,the peak current of the concentration-current curve appears regularly at different concentrations.As the concentration of the solution increases,the cation current flowing through the nanopores with more positive charges on the surface reaches the maximum earlier,while the anion current reaches the maximum later.By appropriately changing the surface charge of the nanopore,we can maximize ion transport at typical concentrations.Effect of nanopore structure on ion migration in lanthanum chloride solution.In order to study the effect of nanopore itself on the transportation of lanthanum chloride solution.A comparative simulation study of lanthanum chloride solution in a water box and a nanopore with a diameter of 3 nm was conducted.The study showed that the nanopore itself was not a solution of lanthanum chloride solution.The ionic current first increased and then decreased.Moving along the z-axis,the magnitude of the ion current at different concentrations is counted,and the concentration-current curve will also show a turning point.In addition,the lanthanum chloride solution formed ion pairs in the water box and nanopores,and it was found that in the nanopores,the proportion of ion pairs formed in the lanthanum chloride solution was higher,and with the concentration of the lanthanum chloride solution With higher and higher,the difference of the paired ratio of ion pairs is also greater and greater,so at high concentrations,lanthanum chloride solution in the nanopores will be significantly higher ion paired ratio.