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Item-typ:Veröffentlichung, Premix membrane emulsification using flat microfiltration inorganic membranes with tailored structure and composition(Elsevier, 2020-04-20); ; ; ; Uniform oil-in-water emulsions were prepared using MCT (medium-chain fatty acid triglyceride, 10 wt%) as the oily dispersed phase and polysorbate 80 as the surfactant (1 wt%). The emulsification process was performed via premix membrane emulsification (PME) using 3 flat microfiltration ceramic membranes with different mean pore sizes (dm): borosilicate (symmetric, commercial, dm: 1.39 μm); SiOC (symmetric, manufactured, dm: 1.76 μm); and mullite (asymmetric, manufactured, dm: 1.18 μm). The droplets size and their distribution varied according to the membrane type and number of permeation cycles (up to a limit of 2 passes). All prepared emulsions presented a tendency to monomodal droplet distribution with span values in the range of 0.82–0.97. The coarse emulsion (premix) droplets were reduced from 6.30 to 4.50–2.17 μm. The asymmetric membrane (mullite) exhibited the highest permeation fluxes at constant relative pressure for both water (43.1 × 10−3 m3 m−2 s−1) and premix (Pass 1: 4.6 × 10−3 m3 m−2 s−1; Pass 2: 5.3 × 10−3 m3 m−2 s−1), still maintaining satisfactory emulsification results.Wissenschaftlicher Artikel132 129 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, Asymmetric mullite membranes manufactured by phase-inversion tape casting from polymethylsiloxane and aluminum diacetate(Elsevier {BV}, 2019-04-02); ; ; ; Polymethylsiloxane (MK) and aluminum diacetate have been stoichiometrically combined to synthesize a mullite-based powder (3Al2O3·2SiO2) at 850 °C (5 h) or 1200 °C (3 h). High-purity crystalline mullite (>99%) was obtained by heating the mixture in the air (thermal oxidation) at 1200 °C for 3 h, mainly due to the for- mation of highly reactive silica and alumina precursors. Afterward, the mullite-based powders were used to prepare planar asymmetric microfiltration membranes by phase-inversion tape casting. The green membranes were sintered at 1600, 1650 or 1700 °C during 2 h. The asymmetric morphology identified in the membranes by scanning electron microscopy analysis reveals a thin skin-layer (microfiltration layer,<10 μm) followed by a porous support, in which two different structures were observed: finger- and/or sponge-like layer. Water permeation performance in a dead-end configuration was investigated at different pressures (3, 4, and 5 bar). The obtained results clearly indicated an improved water permeation flux compared to a symmetric commercial membrane (133.6 m³/m2·h compared to 14.7 m³/m2·h, respectively, at 5 bar). This observation could be ascribed to the asymmetric morphology resultant from the phase-inversion process.Wissenschaftlicher ArtikelBand:581128 120 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, Tape casting of polysiloxane-derived ceramic with controlled porosity and surface properties(Elsevier {BV}, 2018-08-20); ; ; ; Tape casting has been applied to produce porous hybrid and SiOC ceramic tapes using ceramic precursors and commercially available polysiloxanes as polymeric binders. SiC particles of two different mean sizes (4.5 or 6.5 μm) were used as inert fillers to prevent shrinkage and increase mechanical stability. Macroporosity was adjusted by varying the azodicarbonamide (ADA) content from 0 to 30 wt.%. Decomposition of the polysiloxanes at 600 °C resulted in the generation of micropores with high specific surface area (187–267 m2 g−1) and a predominant hydrophobic behavior. At 1000 °C mainly meso/macroporosity were observed (SSA: 32–162 m2 g−1) accompanied by increased hydrophilicity. The influence of ADA content, SiC size, and pyrolysis temperature on open porosity (2.5–37%), average pore size (<0.01–1.76 μm), surface characteristics, and flexural strength (10.5–121 MPa) were investigated. The porous tapes with different surface characteristics and controlled structure are highly promising for applications involving membrane processes, particularly microfiltration systems (0.1–10 μm).Wissenschaftlicher ArtikelBand:38Heft:15146 88