Naohito Yoshikawa

Separation of gaseous mixtures of CO2 and CH4 using a composite microporous glass membrane on ceramic tubing

Abstract Separation of a gaseous mixture of CO 2 and CH 4 was carried out using a microporous, thin glass membrane coated on the surface of a porous ceramic tubing. The glass membrane was prepared by repeating the following procedure: dipping the ceramic tubing into a metal alkoxide solution containing B 2 O 3 , followed by drying, heating and leaching in HCl solution. The thickness of the membrane was in the range of 5-23 μm, depending upon the number of dips. The structure of the membrane was investigated by means of a scanning electron microscope. The mean pore diameter estimated was in the range of 4–64 nm. The maximum separation factor of 1.48 was obtained with the composite membranes which were coated over 15 times with a casting solution in which the ratio of B 2 O 3 : SiO 2 was 0.25:1. Composite membranes with less than 5 coatings showed no ability to separate. When decreasing the content of B 2 O 3 , carbon dioxide seemed to permeate through the composite membrane by the surface diffusion mechanism in the pores.

Simple method for the determination of sulfate ion in salt products by IR diffuse reflectometry.

溶解再製製塩法で製造される高純度塩の不純物は,硫酸イオンが主体であるため,製品の硫酸イオン含有量の管理は重要である.従来より,製品の硫酸イオン含有量の管理は,イオンクロマトグラフ法により行っているが,試料の前処理が必要であり,分析時間も長いため,簡便,迅速な簡易測定法の開発が求められている.そこで,本報告では,赤外拡散反射法による硫酸イオン含有量の簡易測定法について検討した.その結果,赤外拡散反射法により測定した硫酸イオン特有のSO縮重伸縮振動のピーク強度を,試料の充てん状態,粒径及び粒径分布による光散乱度の影響に起因する1900～2090cm-1のKubelka-Munk (K-M)値の変化量及び環境温湿度の影響を絶対湿度で補正することにより,測定誤差±10mg kg-1程度,繰り返し精度4.6%で,高純度塩の硫酸イオン含有量を非破壊で簡易測定できる方法を開発した.本法は,簡易測定に十分な測定精度を持ち,測定時間も1分程度と短時間であるため,製品管理,工程管理に十分対応できると考えられる.