Abstract:
The paper presents a study regarding a possible way for the removal and the recovery of lead (II) and cadmium
(II) ions from wastewaters with relatively high concentrations. The proposed method is based on the precipitation of the
metal ions as oxalates with low solubility in water. A systematic study to establish the optimum conditions for a high
degree of metal recovery as lead oxalate and cadmium oxalate is presented. The studied parameters were: the pH, the
excess of reactant reagents, the initial concentration of ions and the temperature. The crystalline products obtained
correspond to: anhydrous lead (II) oxalate (PbC2O4) and trihydrate cadmium oxalate (CdC2O4*3H2O). The extraction
degree of metals was around 99% for lead (II) and lower, around 70% for cadmium (II). A possible technological flux for
the removal of the studied ions from wastewaters as crystalline oxalates is proposed.
Keywords:
lead, cadmium, oxalate, recovery, precipitation
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