A Tobermorite Ion Exchanger From Recycled Container Glass

Waste container glass cullet has been evaluated as a feedstock material for the hydrothermal synthesis of tobermorite, a cation exchanger. Accordingly, it is demonstrated that essentially phase-pure 11 A tobermorite, Ca5Si6O16(OH)2.4H2O, can be obtained from a stoicheiometrically-adjusted mixture of waste glass cullet and calcium oxide in aqueous sodium hydroxide at 100 deg C. A batch sorption study indicated that the cullet-derived tobermorite is highly effective in the removal of Pb2+ (1.66 mmolg-1) and Cd2+ (0.48 mmolg-1) from solution. Its ion exchange characteristics are compared with those of other waste-derived sorbents and potential applications are discussed.