A press release, issued by Inderscience, via AlphaGalileo, talks about using ground glass for cleaning up polluted water.
Nichola Coleman of the University of Greenwich, London, has developed a simple processing method for converting waste container glass, or cullet, into the mineral tobermorite. Tobermorite is hydrated calcium silicate, silicate being the main material that can be extracted from glass. In the form produced, the phase-pure 11-angstrom form – the mineral can be used as an ion-exchange material that can extract toxic lead and cadmium ions from industrial effluent, wastewater streams or contaminated groundwater.
She has published her findings in the forthcoming issue of the International Journal of Environment and Waste Management. (Reference: Nicola J Coleman, “11 A tobermorite ion exchanger from recycled container glass” in Int. J. Environment and Waste Management, 2011, 8, 3/4, 366-382)
To make the tobermorite, Coleman simply heats a mixture of ground cullet, lime (as a calcium source) and caustic soda (sodium hydroxide solution) to 100 degree celsius in a sealed Teflon container. Initial tests show that uptake of lead and cadmium from solution are rather slow, so Coleman suggests that, at this stage of development, the synthetic mineral might best be used in the in situ remediation of groundwater rather than in industrial ex situ effluent filtration processes. The concept is now being extended to create other classes of ion exchange filter from unrecyclable and low-quality waste glass.
