Film Diffusion Of Ions As Considering The Impact Of Electric Field From Soil Particle Surface

Ion diffusion is an important style of mass transport in soil, which may contronl the movement of nutrients from bulk soil to plant roots as well as the fate of potentially harmful salts and toxic compounds. The diffusion of ions can also play a significant role in bioavailability and adsorption kinetics of nutrients. Fick's laws are used to determine the diffusion coefficient of ion in soil. Many researchers have revealed that many factors influence the diffusion coefficient, e.g..water content, soil texture, CEC and so on. However, all of these researches bear the same limitation that the effect of the electric field from soil particle surface on ion diffusion was not considered. Whereas there is a magnitude electric-field in soil system, it is necessary to consider the influence of electric-field in the research of ion diffusion in soil. The establishment of an easy approach to measure the surface potential and a simple linear theory for describing ionic diffusion providing the theory and method bases in the research of ion diffusion in soil as considering the effect of electric-field from soil particle surface.The kinetic method has been used in this experimental study to determine the surface charge properties. Neutral purple soil and latosol were taken as the experimental materials. The charge quantity, the surface potential, the surface charge density, the surface electric field strength and SSA was measured. The experimental result has compared between the two different soils. The effect of electrolyte concentration, temperature, electrolyte type and pH on the surface charge properties was studied, too. We also used the kinetic method to study K⁺, Mg²⁺ diffusion in the two soils under the same condition as we determine the surface charge properties. The ion diffusion kinetics in two soils has been discussed. And the diffusion flux dependent of time and diffusion coefficient in two soils diffusion efficient were determined. The experimental result as follows:Firstly, in the 2:1 electrolyte type, the surface potential of the neutral purple soil and latosol is...