Ageing of microporous silica

Abstract

A silica sol was frozen and then thawed yielding a suspension of plate-like silica which when dried gave a sample which was almost entirely composed of micropores. The silica aged when left to stand in the laboratory, but reached a constant value of activity after a period of about six months or less. No apparent change in microporosity occurred during tne ageing process.Several selected samples were sintered at temperatures up to 800" at which point virtually all the adsorption capacity of the adsorbent was destroyed leaving adsorption to take place only on the external surface.