摘要:
Adsorption of carbon dioxide from gas streams at temperatures in the range of 300 to 500° C. is carried out with a solid adsorbent containing magnesium oxide, preferably promoted with an alkali metal carbonate or bicarbonate so that the atomic ratio of alkali metal to magnesium is in the range of 0.006 to 2.60. Preferred adsorbents are made from the precipitate formed on addition of alkali metal and carbonate ions to an aqueous solution of a magnesium salt. Atomic ratios of alkali metal to magnesium can be adjusted by washing the precipitate with water. Low surface area adsorbents can be made by dehydration and CO2 removal of magnesium hydroxycarbonate, with or without alkali metal promotion. The process is especially valuable in pressure swing adsorption operations.
摘要:
A faujasite aluminosilicate with a Si/Al ratio in the range of 1.05 to 1.26 having an non-uniform aluminum distribution, synthesized by crystallizing the zeolite from a mixture of alkali metal aluminate and alkali metal silicate wherein the mixture has an alkali metal oxide to silica ratio of at least 1.6 and a water to alkali metal oxide ratio of at least 37. The X-zeolite has utility as a gas separation adsorbent such as separating oxygen from nitrogen in air.