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Virtual poster session
Adapting polymer derived ceramic membranes for emulsification processWednesday (07.10.2020) 19:40 - 19:43 Room 1 Part of:
Porous membranes with well-defined pore sizes present great potential applications in water treatment and emulsifications process. Ceramic membranes can be synthesized via cross-linking and pyrolysis of a suitable polymeric precursor, at lower temperatures, originating a new class of materials denominated polymer-derived ceramics (PDC). Preceramic polymers can be processed or shaped using usual polymer-forming techniques. The structure and surface characteristics of PDCs can be easily tailored by changing the chemical nature of the starting precursor and the pyrolysis conditions. Therefore, the proper combination of raw materials and processing techniques produces a porous PDC structure with appropriate characteristics to meet the requirements for different membrane applications. In this study, asymmetric porous SiOC membranes with different pore characteristic and membrane morphology were produced by adapting the phase-inversion tape casting technique to the PDC route. Polymethylsiloxane was used as a ceramic precursor. The produced tapes were pyrolyzed under N2 atmosphere. The structure and surface characteristics were tailored by changing the pyrolysis temperatures (600 and 1000 °C) and the additives contents, such as and polyvinylpyrrolidone and solid loading. Scanning electron microscopy analysis revealed the asymmetric morphology composed by a thin skin-layer (average pore size < 2 µm) and a sponge-like support. The differences in membranes porosity (33-47%) and overall pore size distribution (1 - 10 μm) can be controlled according to the slurry composition. Higher mechanical strengths and enhanced hydrophilic character were associated with the higher pyrolysis temperature (ceramization process). The water permeation performances of membranes pyrolyzed at 1000 °C were assessed in a dead-end configuration device under different pressures (1 – 3 bar). The obtained water permeation fluxes (5 – 55 m3/m2.h, at 3 bar) indicated the advantages of the asymmetric structure - a porous skin-layer followed by a porous support-layer which minimizes mass transport limitations. Preliminary premix emulsification tests showed that the number of cycles and the overall pore size of the membrane present the most significant influences on the droplet size distribution. It turned out that the phase-inversion tape casting technique is a flexible and promising alternative to produce tailorable PDC membranes suitable for emulsification applications.
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