Pervaporation of benzene–cyclohexane mixture by poly(γ‐methyl L‐glutamate) membrane and synergetic effect of their mixture on diffusion rate

Abstract

AbstractThe pervaporation of binary liquids mixture of benzene and cyclohexane was examined by use of poly(γ‐methyl L‐glutamate) (PMLG) membrane. The permeation rate–time curve for each of benzene and cyclohexane from their mixtures changed to the longer times side by increasing the cyclohexane in the mixtures. t1/2 (the time required to reach a half‐value of the steady state permeation rate) for the each component increased exponentially with increasing of cyclohexane, which has a smaller plasticizing effect on PMLG membrane than benzene, in the mixtures. The apparent diffusion coefficients, obtained from the steady state permeation and the sorption experiments, for benzene–PMLG and cyclohexane–PMLG are dependent exponentially on the sorbed amounts of benzene. This result was explained on the bases that the diffusion of cyclohexane was enhanced synergetically with benzene coexisting in the system. This effect influenced negatively the separation of the liquids mixture by pervaporation.