Copper adsorption by natural manganese dioxide

The adsorption of copper ions was investigated using pyrolusite ore as a low-cost alternative adsorbent source. Pyrolusite, which contains mainly MnO2, is a manganese ore. The effects of the initial concentration of copper(II) ions, initial pH of solution, adsorbent dosage and particle size on the adsorption process were examined. It was found that the percentage of the adsorbed copper increases with increasing the amount of adsorbent. It was observed that the maximum adsorption occurred at natural initial pH values for all copper concentrations. While the initial solution concentration, initial pH, contact time, stirring speed, particle size and adsorbent dosage were 2.5 mmol/L, natural, 180 min, 200 r/min, 120 μm and 6 g/L, respectively, the efficiency of copper adsorption on pyrolusite ore was 96.5%. The isotherm and kinetic studies relating to this adsorption process were also made. It was determined that the equilibrium data followed the Langmuir isotherm model while the process kinetic could be described by the pseudo-second order kinetic model.