Efficiency of removal Cr(III), Ni(II), Pb(II) ions from simulated wastewater using natural and modified Ca - bentonite

The aim of this study was to investigate removal efficiency of heavy metals and the adsorption capacity of natural Ca-bentonite, as well as thermally and acid-activated Ca-bentonite (with HCl and H2SO4) for the removal of heavy metal ions Cr(III), Ni(II) and Pb(II). The adsorbent used is bentonite from the Shipovo (Šipovo mine), Bosnia and Herzegovina. The results show that the efficiency of heavy metal ion removal using Ca-bentonite is at a satisfactory level. Thus, the highest percentage of removal for the tested metals was at the highest concentration of 20 mg/L, while the decrease in concentration decreased the efficiency of removal of heavy metal ions. The highest percentage of removal was recorded for Cr(III) ions, while the lowest was for Ni(II).