A novel catalytically active membrane with highly porous catalytic layer for the conversion enhancement of esterification: Focusing on the reduction of mass transfer resistance of the catalytic layer

- A catalytic layer with highly inter-connected sponge-like pores was prepared.
- PVP was an optimal pore-forming additive to increase the membrane porosity.
- Porosity of the membrane was as high as 81.6%.
- Catalytic layer resistance decreased from 48.5% to 20.6% of overall resistances.
- CAMR with pCAM showed a best reaction-pervaporation coupling performance.

A composite catalytically active membrane was prepared focusing on the reduction of membrane mass transfer resistance to achieve a better esterification-pervaporation coupling performance. The effect of membrane preparation conditions on the membrane morphology was first evaluated. Under an optimized membrane preparation conditions, a “sandwich-like” composite membrane with a highly inter-connected sponge-like catalytic layer on a polyvinyl alcohol / polyethersulfone bilayer was obtained. The porosity of the membrane was found to be as high as 81.6%. A simple resistance-in-series model was developed to analyze the mass transfer resistance distribution in a traditional inert membrane reactor (IMR), a catalytically active membrane reactor (CAMR) with dense catalytic layer and a catalytically active membrane reactor with porous catalytic layer, respectively. Results showed that the preparation of a highly porous catalytic layer decreased the resistance of catalytic layer from 48.5% to 20.6% of overall resistances, leading to an enhanced water removal ability for the composite membrane. Finally, reaction-separation coupling experiments in IMR, CAMR with porous catalytic layer and CAMR with dense catalytic layer showed that, with a faster reaction kinetics and water removal rate, CAMR with porous catalytic layer exhibited a best coupling performance.