Mixed matrix membranes with hybrid star-shaped macromolecules for mono- and dihydric alcohols pervaporation

• Mixed matrix membranes consist of HSM in PPO matrix.
• Pervaporation and sorption of methanol and ethylene glycol are studied.
• Total flux and permeability as well as separation factor and selectivity are compared.
• Membrane containing 5 wt.% HSM exhibits maximal total flux and separation factor.

Mixed matrix membranes were obtained by including hybrid star-shaped macromolecules (HSM) in a matrix of polyphenylene oxide (PPO). HSM filler was a twelve-arms star with six polystyrene arms and six diblock copolymer poly(2-vinylpyridine)-b-poly(tert-butylmethacrylate) arms grafted onto a fullerene C60 center. The PPO/HSM membranes structure was studied by scanning electron microscopy and the energy dispersive spectrometry. Mass transfer through PPO/HSM membranes was studied by sorption and pervaporation tests toward methanol and ethylene glycol. In the pervaporation of methanol – ethylene glycol mixture over the concentration range of 5–30 wt.% methanol in feed, all membranes showed high affinity to methanol and produced permeate concentrated in methanol. The total flux through the membrane increased with the growth of both the HSM content in membrane and the methanol concentration in the feed. Separation factor achieved maximal magnitude at the filler concentration in membrane equal to 5 wt.% HSP. To evaluate intrinsic properties of the penetrant – membrane system, permeability and selectivity were calculated. The dependence of methanol permeability on methanol concentration in the feed was opposite to that of the flux. It was shown that PPO/HSM membranes exhibit the best properties when the feed enriched with ethylene glycol.

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