Synthesis of Double-Layer Silicates from Recycled Glass Cullet:  A New Type of Chemical Adsorbent

Curbside recycling of glass bottles and jars has been extremely successful. Those glasses that are sorted by color are a marketable commodity; those that are not have no immediate commercial value and must be disposed of in landfills. With proper chemical treatment, however, mixed-glass cullet can be transformed into claylike chemical adsorbents. By mixing ground glass cullet with either alkali hydroxide or alkali carbonate solutions one is able to form a hydrous double-layer silicate known as rhodesite (NaKCa2[Si8O19]·5H2O). Tests of the adsorptive and cation exchange properties of glass cullet derived materials have shown them to have properties comparable to natural clays and zeolites. Whereas natural materials tend to become “sticky” and/or lose their granularity when wet, rhodesite-based adsorbents do not.