Masakazu Horio

Adsorptive and photocatalytic performance of TiO2 pillared montmorillonite in degradation of endocrine disruptors having different hydrophobicity

Abstract TiO 2 pillared clay was applied for the adsorption-photocatalytic degradation of the endocrine disruptors with various hydrophobicities (di- n -butyl phthalate, diethyl phthalate, dimethyl phthalate and bisphenol-A). The hydrothermal treatment developed the crystallinity of the TiO 2 pillar and the size of the TiO 2 crystallites, and enhanced the photocatalytic degradation rate. However, the hydrothermal treatment in hard condition made the specific photocatalytic activity decrease since the size of crystallites increased. The surface hydrophobicity of the pillared clay was not affected so much, but reduced slightly, by the hydrothermal treatment. Higher hydrophobic endocrine disruptor was more adsorbed and enriched on the TiO 2 pillared clay. Enrichment of the reactant enhanced the rate of photocatalytic degradation on the pillared clay.

High surface area alumina aerogel at elevated temperatures

In order to obtain an alumina with a high surface area at elevated temperatures, a suppression of the θ–α phase transformation of alumina by decreasing the bulk density has been attempted. The abundance of the lattice defects and dislocations in the neck region would be a favourable site for nucleation of the α-phase. Therefore the decrease of the neck region, that is, the decrease in bulk density would lead to a suppression of the θ–α phase transformation. In order to decrease the bulk density, the alumina aerogel was prepared from boehmite sol. The bulk density was varied from 0.06 to 1.1 g cm–3 by decreasing the ζ-potential of the boehmite particles during ageing. The phase transformation and the surface area of alumina from aerogels with various bulk densities were examined at elevated temperatures. The phase-transformation temperature increased with decreasing bulk density. While the alumina with its bulk density of 1.1 g cm–3 transformed to the α-phase at 1443 K, alumina aerogel with a bulk density of 0.06 g cm–3 transformed to the α-phase at 1573 K. The shift of the transformation to a higher temperature can be understood in terms of the decrease in the neck region. As a result of the suppression of phase transformation, a large surface area was maintained at elevated temperatures. After heating at 1473 K for 5 h, the alumina aerogel, with a bulk density of 0.06 g cm–3, was composed of the θ-phase and its surface area was 90 m2 g–1. After completion of the phase transformation, i.e. at 1673 K for 5 h, alumina aerogel with a bulk density of 0.06 g cm–3 still exhibited a surface area of 10 m2 g–1, larger than that of the conventional α-phase.

Control of the distance between the silicate layers of hectorite by pillaring with alumina in the presence of polyvinyl alcohol

Varying The Concentration Of An Aluminium Chlorohydroxide Solution Is Found To Result In A Systematic Alteration Of The Distance Between The Silicate Layers On Pillaring Hectorite With Alumina In The Presence Of Polyvinyl Alcohol.

Characteristics of Clay Materials for the Separation of Carbon Dioxide from N2-CO2 Mixture by Gas Chromatography.

Characteristics of clay materials for the separation of carbon dioxide from N2-CO2 mixture have been investigated by gas chromatography. The separation ability is evaluated by the difference in the reten tion times for carbon dioxide and nitrogen. Zeolite and sepiolite exhibit the separation ability up to 673k, while montmorillonite, saponite and silica gel show no separation ability above 573 K. The relatively higher separation ability of zeolite and sepiolite is attributed to the relatively higher heats of adsorption for carbon dioxide than those for nitrogen and their higher surface areas.

Preparation of Alumina Pillared Synthetic Fluorohectorite with Specific Gallerey.

ポリビニルアルコール(PVA)共存下でアルミナ架橋合成フッ素ヘクトライトを調製し,そのキャラクタリゼーションを行った。PVAと合成フッ素ヘクトライトの混合比を一定(2.09-PVA/9-Clay)にしておいて塩化水酸化アルミニウム(aluminumchloridehydroxide,ACH)濃度を0.15～0.89wt%の範囲で変えて調製した架橋体の層間隔およびピラー量は,ACH濃度に比例してそれぞれ8.90～19.3A,0.051～0.219-A1203/9-Clayであった。次にACH濃度を0.66wt%としてPVA混合比を0～30g-PVA/9-Clayの範囲で変えて調製した架橋体の層間隔は,PVA混合比の増加とともに0大きくなり,2.09-PVA/9-Clay以上では19.1Åで飽和した。ACH濃度を2.9wt%に増やして層0間隔を調べたところ,0～5.09-PVA/9-ClayのPVA混合比で飽和することなく8.6～22.3A変化することが確認された。PVAを使用せずに調製した架橋体の層間隔は,ACH添加量に関係なく約のくき9Aであった。ピラー0間距離は層聞隔に反比例し,8.9Å の層間隔を有する架橋体のピラー間距離は20,19.3Åの層間隔を有する架橋体のそれは12Åと推算された。以上のことから次のことが結論された。アルミナ架橋合成フッ素ヘクトライトの層間隔およびピラー間距離はACH濃度あるいはPVA混合比を変えることにより制御することができる。PVAはシリケート層間に存在し,ピラーが成長するために必要な層空間を保持する役割を担う。