Reactive sintering and particle morphology control of β″-alumina-based water purification filters

This paper reports on the preparation of porous membranes consisting of plate-like β″-alumina grains and the evaluation for microfiltration properties. Porous β″-alumina-based ceramics were prepared by the solid-state reactive sintering of Na2CO3 and α-Al2O3 at 1100–1300 °C. To study the effect of impurities in the starting powder mixtures, LiF-doped membranes were also prepared. As for the water filtration test, the turbidity before and after the vacuum filtration was measured using sintered porous membranes. To simulate bacteria-contaminated water, a suspension of a commercial boehmite powder (D50 = 0.7 μm) in distilled water was used. The non-doped samples sintered at 1200 °C were composed of β″-alumina (84 wt%) and β-alumina (16 wt%) grains and showed a good microfiltration performance; the turbidities before and after filtration were 894.4 NTU and 1.46 NTU, respectively

Fabrication of hierarchically porous monolithic layered double hydroxide composites with tunable microcages for effective oxyanion adsorption

Removal of toxic substances from industrial wastes is an urgent issue for realizing a sustainable society. Layered double hydroxides (LDHs) are expected to be an effective adsorbent for toxic anions, especially oxyanions, because of their high anion adsorption capacity and reusability. Monolithic LDH materials with rational meso- and macropores are expected to show high adsorption capacity/rate towards targeted toxic substances owing to their large specific surface area and liquid transport property. Besides fabricating hierarchical pores, size control of microcages in LDH crystals is required to achieve selective removal of oxyanions. Herein, we prepared hierarchically porous monolithic LDH composites with tunable microcages by changing the combination of cationic species in the LDH crystal. Monolithic Mg-, Mn-, Fe-, Co- and Ni-Al type LDH composites with hierarchical pores were successfully prepared via an epoxide-mediated sol-gel reaction accompanying with phase separation. The monolithic Co-Al type LDH composite with hierarchical pores exhibited the highest CrO42− adsorption capacity because its microcage size well fits the CrO42− size. Also Co-Al type LDH composite adsorbed different oxyanions, depending on their affinity with the LDH, in SO42−, CrO42−, MoO42− and HVO42− co-existing solution. The pore size controllability in discrete length-scales of micrometers, nanometers, and picometers offers LDHs with tailored surface chemistries and physical properties desirable for effective and selective oxyanion adsorption.The study was supported by JSPS KAKENHI (No. 26288108, 26630322).This work is partially supported by the Kazuchika Okura Memorial Foundation and the Hosokawa Powder Technology Foundation

顎顔面軟組織の弾性に対するTwin Block Appliance療法の効果

下顎後退によるクラスII不正咬合患者13名(男6名、女7名、平均9.8±1.4歳)を対象に、顎顔面軟組織の弾性に及ぼすTwin Block Appliance(TBA)療法の効果について調べた。クラスI不正咬合患者14名(男7名、女7名、平均9.2±1.7歳)を対照とした。クラスII患者にはTBAを施した。初診時、左鼻翼と口角の中点、右鼻翼と口角の中点、soft tissue pogonionの弾性値は対照群に比べクラスII群で有意に低かった。TBA療法の結果、クラスII群は下顎の前方成長と下顎前歯の唇側傾斜を示した。1年後、軟組織の弾性値は対照群と変わらなかった