Asymmetric polysiloxane-based SiOC membranes produced via phase inversion tape casting process

Asymmetric porous SiOC membranes with different pore characteristic and membrane morphology were produced for the first time by adapting the phase inversion tape casting technique to the polymer-derived ceramic route. Polymethyl siloxane (MK) was used as a ceramic precursor. The produced tapes were pyrolyzed under N-2 atmosphere. The structure and surface characteristics were tailored by changing the pyrolysis temperatures (600 and 1000 degrees C), polyvinylpyrrolidone and solid loading. Scanning electron microscopy analysis revealed the asymmetric morphology composed by a thin skin-layer (average pore size <2 mu m) and a sponge-like support. The differences in membranes porosity (33-47%) and overall pore size distribution (1-10 mu m) can be controlled by adjusting the slurry composition. The incorporation of particles improved the slurry processability, enhanced the mechanical flexural resistance of the membrane (20-48 MPa), and reduced the average pore size. Higher mechanical strengths and enhanced hydrophilic character are associated with higher pyrolysis temperatures (ceramization process). The water permeation of membranes pyrolyzed at 1000 degrees C were assessed in a dead-end configuration device under different pressures (1-3 bar). The obtained water permeation fluxes (6-55 m(3)/m(2).h, at 3 bar) indicates the advantages of the asymmetric structure which minimizes mass transport limitations. (C) 2020 The Author(s). Published by Elsevier Ltd.

Automated summary

Asymmetric porous SiOC membranes with different pore characteristics and morphology were successfully produced using the phase inversion tape casting technique. By adjusting the pyrolysis temperature and slurry composition, the structure and surface characteristics of the membrane can be tailored, resulting in improved mechanical strength and water permeation fluxes. The asymmetric structure of the membranes was found to minimize mass transport limitations, showing advantages in water filtration applications.