A thermodynamic study of 1,4-dioxane across cellulose acetate membrane under different conditions

The cellulose membrane used in the present studies was prepared by impregnating cellulose acetate dissolved in acetone and mixed up with aqueous KBr, which has been added through a sintered G2 (porosity) disc. The flow of water, 1,4-dioxane and their different compositions through this membrane has been measured at different temperatures under different electric and magnetic field strengths. The results are interpreted in terms of a unit rate process. The electro osmotic permeability coefficients, enthalpy of activation (ΔH*), entropy of activation (ΔS*), free energy of activation (ΔG*), number of pores, pore radius and zeta potential have also been calculated. The flow process of various aqueous–dioxane mixtures across the membrane does not seem to be thermodynamically feasible. However, the dipolar nature of the solvent mixture does affect the membrane structure as shown by the variation in pore radius, number of pores and zeta potential.

► Studies are used for biomedical separations and demineralization by reverse osmosis.
► Flow time is measured at different temperatures, electric and magnetic field strengths.
► Interactions of solvents affect the alignment of dipoles under applied fields.
► Pore radius, no. of pores, zeta potential reflect their effect on the membrane structure.
► ΔG* in all cases shows that flow is not favoured across the porous medium.