A study of the uptake of copper ions by nanostructured calcium silicate

Presented is a study of the removal of copper ions from dilute aqueous solutions by nanostructured calcium silicate. Two different copper sources, copper nitrate and copper chloride, at various concentrations ranging from 10 to 5000 mg kg−1 copper have been investigated. The uptake of copper ions from aqueous solutions at concentrations below 500 mg kg−1 is 97% and higher within 30 min at silicate loadings of 1 g kg−1. The formation of crystals of copper hydroxide nitrate, Cu2(OH)3NO3, and copper chloride hydroxide, Cu2(OH)3Cl, on the surface of the silicate have been observed. Reaction rates and possible mechanisms characterising the uptake have been investigated and discussed.