| 摘要 |
PROBLEM TO BE SOLVED: To determine an exchange time with a change of a color tone due to a reaction with a subject gas without destroying or contacting by depositing a metallic ion on a filter material using an ion exchanger. SOLUTION: In the metallic ion deposited on the filter material, the color tone is changed by allowing the metallic ion to contact with a gas to be adsorbed, and especially the color tone change due to a complex formation is large, and the metallic ion is selected preferably among inexpensive copper, nickel and cobalt. A depositing amount of the metallic ion may be in the lowest degree capable of detecting the color tone change. The gas to be adsorbed is ammonia, trimethylamine, hydrogen chloride, etc. A strongly acidic cation exchanger containing a sulfon group, a weakly acidic cation exchanger containing a carboxyl group, etc., are applied as the ion exchanger. In addition to this, a graft polymer produced by a radiation-induced graft polymerizing method is preferable. The color tone change is detected with a naked eye when a concn. of the subject gas is high, but the exchange time is determined by using a measuring instrument such as color difference meter at low concn. region. |
