Removal of Zn2+, Fe2+, Cu2+, Pb2+, Cd2+, Ni2+ and Co2+ ions from aqueous solutions using modified phosphate dolomite

In the present work, modification of phosphate dolomite was conducted and applied for some bivalent metal ions removal. Physico-chemical properties of sorbent were characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), differential-thermal analysis (DTA), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and low temperature adsorption–desorption of nitrogen. Sorption properties of modified dolomite for Zn2+, Fe2+, Cu2+, Pb2+, Cd2+, Ni2+ and Co2+ removal were studied using model solutions. The highest removal efficiency was observed in pH range from 2 to 5. Among all tested metals, highest adsorption capacity of phosphated dolomite was detected towards Co2+ and Pb2+ (15 and 12 mmol g−1, respectively) and the lowest towards Zn2+, Fe2+ and Cu2+ (about 8 mmol g−1). Adsorption isotherms were built for each tested metal ions and were fitted to Langmuir, Freundlich and Redlich–Peterson models.