Abstract:

The equations of rejection of monovalent electrolyte ion，rejection of neutral molecule and solution permeation flux for multi-solute solution on porous charged membrane，and then expression of molecule concentration ratio were derived based on the equations of solute rejection and solution permeation flux on porous membrane under the zero charged condition.Based on the function properties of equations，the relationships of monovalent electrolyte ion and neutral molecule rejection vs solute concentration and permeation flux vs solute concentration were discussed for multi-solute solution.The minimal and maximal values were predicted on the curves monovalent electrolyte ion rejection and neutral molecule rejection vs solute concentration and permeation flux vs solute concentration.The following conclusions were obtained：（1）As pH value increased，the order of cation and anion rejection was from R _M⁺ > R _X^- > R _H⁺ to R _M⁺ =R _X^- > R _H⁺ again to R _X^- >R _M⁺ > R _H⁺ . The minimal and maximal value of ion rejection could be observed on the curves of ion rejection vs pH value.（2）The equation of total organic acid rejection could explain the physical significance of parameters of the related expressions reported in reference.It could explain the reason for the predicted curve of rejection vs pH value for PABA solution by such expressions in reference was higher than the experimental values.The rejection of PABA in methyl alcohol solution was discussed.（3）The concentration ratio of ion could depend on the ion composition and the concentration ratio of corresponding salt.R M+