Structure and properties of highly selective and active Advanced Ion Exchange (AIX) materials.
Enabling and expanding sustainable metal recovery
Environmental contamination and loss of metal values resulting from wastewater containing transition metal ions is widespread. New composite materials have been developed for the recovery and purification of precious and base metals from Active Pharmaceutical Ingredients (API) manufacture, Platinum Group Metals (PGM) refining, base metal mining and metal processing industries. The manufacture of these materials is based on grafting active adsorption sites on the outer surfaces and large pores of silica, or attaching polymeric chains of active adsorption sites to non-porous polymer fibres. The advantages the new AIX materials offer over conventional polystyrene resins are discussed.
In the field of Active Pharmaceutical Ingredients (API’s) there is a significant loss of precious metal catalysts such as Pt and Pd in hazardous waste water effluents. This represents a significant loss of monetary value but recovery at low concentrations in potent waste streams is challenging. One pharmaceutical waste stream was found to contain 20 kg of soluble Pd per year, and recovery using one of the AIX materials described has resulted in significant process cost saving, more than offsetting the cost of waste water disposal.
An important source of base metal contamination is from acid mine pits and in the waste water from metal refiners. Increasingly, tightening of the regulations controlling natural resource extraction and industrial wastewater discharge is driving an interest in removal and recovery of these ions from waste streams as well as the remediation of contaminated sites. The economic incentives of recovering valuable ions such as copper and nickel are high, and the value of the recovered metal can offset remediation costs and for high flow waste streams can be a source of income. In order to economically treat t ...