Adsorption of Ni 2+ ions by phosphate and carbonate adsorbents

The adsorption of Ni2+ ions by sorbents based on dolomite thermally activated at 800 °C (D-800), phosphated dolomite (PD), and Zr-modified PD (PD-Zr) was studied. It was found that D-800 sample was characterized by the highest sorption capacity (364 mg/g), while at the initial concentration of Ni2+ ions of 300 mg/L, the purification of aqueous solutions to the MPC standards for drinking water (< 0.1 mg/L) was achieved, and at C0 (Ni2+) of 50 mg/L, deep purification to a residual concentration of < 0.01 mg/L occurred. It was revealed that the absorption of Ni2+ ions by the D-800 sorbent is due to the heterogeneous precipitation of nickel hydroxicarbonate, and in the case of the PD sorbent, nickel hydrophosphate is formed. The results of desorption of Ni2+ ions from saturated sorbents indicated the occurrence of ion exchange with the participation of amorphous zirconium phosphate for the PD-Zr sample. The lowest desorption degree (