Water contaminated with tiny oil emulsions is costly and difficult to treat because of the colloidal stability and deformable nature of emulsified oil. This work utilizes carbon nanotubes (CNTs) in macro/mesopore channels of ceramic membrane to remove tiny oil droplets from water. The CNTs were implanted into the porous ceramic channels by means of chemical vapor deposition. Being hydrophobic in nature and possessing an interfacial curvature at nanoscale, CNTs enabled tiny oil emulsion in submicrometer and nano scales to be entrapped while permeating through the CNTs implanted pore channels. Optimizing the growth condition of the CNTs resulted in a uniform distribution of CNT grids, which allowed the development of lipophilic layers during filtration. These lipo-layers drastically enhanced the separation performance. The filtration capability of CNT-ceramic membrane was assessed by the purification of a dilute oil-in-water (o/w) emulsion containing ca. 210 ppm mineral oil 1600 ppm emulsifier, and a trace amount of dye, a proxy polluted water source. The best CNT-tailored ceramic membrane, prepared under the optimized CNT growth condition, claimed 100% oil rejection rate and a permeation flux of 0.6 L m(-2) min(-1), driven by a pressure drop of ca. 1 bar for 3 days on the basis of UV measurement. The CNT-sustained adsorption complements the size-exclusion mechanism in removing soluble oil.

A matrix with extensively interconnected channels is an important feature to pursue ceramic membrane technology. This work attempts an alternative pore‐forming strategy through utilizing in situ generated poly(p‐phenylene terephthalamide) (PPTA) nanorods as a pore former. Different from the conventional means, this approach relies on interstice exclusion of the PPTA rods throughout the green ceramic object. The spatial confinement restricts the polymerization extent of PPTA, resulting in a localized generation of nanocrystallite rods and an expansion of interparticle contacts simultaneously. Another feature of this PPTA is the high carbonization degree of PPTA which allows for space retention of the rods during the initial stage of calcination designed to sinter the object. The pore channels left behind in the sintered article possess the throat‐to‐void structural characteristic. Besides the marked improvement on fluid permeability and mechanical strength over the ones fabricated by using starch as pore former, such a pore structure claims an unusual capability to induce a shear thinning effect when a pressure‐driven dilute polymer solution passes through the channels.

A new processing method for the fabrication of porous ceramic membrane has been developed via a three-step procedure: by uniformly distributing a solid vinyl monomer (e.g., acrylamide) into a green object of ceramic through wet chemistry mixing and compression molding; polymerizing the monomer in a highly compact surrounding, leading to the formation of embedded chain assemblies of polyacrylamide; and removing the polymer via carbonization and calcination. This in situ pore-forming strategy grants less tortuous and well-interconnected pore channels in contrast to the approach of using polymeric porogen such as starch or cellulose. The weight% of initiator and duration of polymerization were scrutinized using thermal analysis, electron microscopy, and Hg porosimetry to understand their influences on the porous structure of sintered ceramic membrane, e.g., a thin Yttria-stabilized zirconia disc, and ultimately its gas permeability. The advantage of this pore-forming method lies in the fact that the monomer can be homogenously distributed in the green object in a confined space and the polymer chains formed during the in situ solid state polymerization can develop space occupancy through chain penetration and association, thus leaving behind interconnecting pore channels and more open pores after they were removed eventually. In this study, it has been shown that the resulting porous ceramics manifests a marked improvement (20-80%) in gas permeability over those fabricated by using starch as the pore-former. Furthermore, the porous ceramics fabricated by the new method exhibited higher rapture resistivity on the similar porosity basis.

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Compositing fluorite Ce0.8Gd0.2O2-δ (CGO) oxide with perovskite La0.4Ba0.6Fe0.8Zn0.2O3-δ (LBFZ) oxide leads to the formation of a minor interfacial BaCeO3 phase upon sintering at 1400 °C. This interfacial composition assures a gastight ceramic membrane with fine grain-boundary structure, in which the LBFZ phase exhibits an improved oxygen permeability over the pristine LBFZ membrane on the same volumetric basis. The presence of the BaCeO3 phase effectively preserves the structural integrity of the composition by limiting the interfacial diffusion of barium ions between LBFZ and CGO. In comparison, replacing CGO with Y0.08Zr0.92O2-δ in the system results in a substantially low oxygen flux due to an overwhelming interfacial diffusion and, consequently, a heavy degradation of LBFZ. Besides structural reinforcement, the high interface between LBFZ and CGO benefits oxygen transport, as is proven through variation of the oxygen partial pressure on the feed side of the membrane and operation temperature. Furthermore, the trade-off between LBFZ loading and interfacial diffusion yields an optimal CGO loading at 40 wt %, which exhibits an oxygen flux of 0.84 cm(3)/cm(2)·min at 950 °C. In summary, the minor interfacial binding between CGO and LBFZ grains is constructive in easing oxygen crossover in the phase boundary with the exception of maintaining membrane structural stability under oxygen permeation conditions.