反渗透过程溶质脱除率方程

EQUATION OF SOLUTE REJECTION RATE IN REVERSE OSMOSIS PROCESS

溶解扩散理论、摩擦模型和表面力-孔流模型假设稳态时膜中溶质通量恒定“-”。本文分 析了该假设存在的理论依据,并基于膜的吸附-扩散模型’‘’建立了反渗透过程溶质脱除率方 程。

The transfer equations of solute and solvent in membrane are derived in this paper. If the permeation flux of solute is constant,the velocity of solute molecules should not be constant. There are some problems arising from the force equilibrium of friction model and surface force -pore flow model, i. e. the assumption of constant permeation flux of solute does not agree with the force equilibrium conditions. On the basis of the model of membrane adsorption diffusion, the equation of solute rejection rate is derived to describe the case of preferential adsorption of solute and solvent. When the mass transfer coefficient of the high pressure side of membrane k approaches infinity, solute rejection rate is independent of membrane thickness. The first order approximation of the equation of solute rejection rate is similar to the equation of solute rejection rate in Sourirajan theory and solution diffusion model. When the solvent is adsorbed preferentially on the membrane surface, solute rejection rate increases as feed speed increases. When the solute is adsorbed preferentially on the membrane surface, solute rejection rate decreases as feed speed increases.