The effect of β-dicalcium silicate, α-monocalcium silicate and calcium hydroxide upon the removal of lead (pb2+) ions from aqueous solution

A study was conducted of the influence of pH, initial reactant concentration and reaction time upon the rate of removal of lead ions from solutions of lead nitrate. Three different reactants were used: β-dicalcium silicate (β-C₂S)*, α-monocalcium silicate (α-CS), in the form of finely ground clinkers, and commercial calcium hydroxide. The initial concentration of lead in solution was varied between 5 and 1000 mg cm^-3 Pb²⁺ for different additions of reactant. For each concentration of lead ion the effect of time of shaking on the removal of lead was followed by the determination of residual lead concentration in the filtrate. Lead was reduced to low levels by all the precipitants. The precipitated reaction products were identified by X-ray diffraction techniques, electron diffraction analysis and infrared spectroscopy. The analysis characterised the products of the precipitation reactions as basic lead carbonate, basic lead nitrates and lead hydroxide.