Modified silicas for clean technology

A wide variety of novel materials can be prepared through the chemical modification of silica gels with organic and inorganic functionalities. In addition to their use in chromatographic separations, they have been increasingly used as catalysts in liquid phase organic reactions. It is the application of these materials as viable, more environmentally friendly, alternatives to traditional homogeneous catalysts that forms the main body of this review. Their use as efficient materials for the selective pre-concentration of trace metals from aqueous systems is also discussed.