Investigation Of Adsorption Capacity Of Ledi?�?s Afar Region Natural Bentonite For Removal Of Pb (II), Cd (II) And Cu (II) From Aqueous Solution

Abstract

Bentonite clay in its natural form, obtained from Afar region, near Ledi river, was utilized as a low-cost adsorbent for removal Cu2+, Cd2+and Pb2+ ions from aqueous solution. This clay material was characterized with X-ray diffraction and elemental analysis (complete silicate analysis). Batch adsorption experiments were carried out as a function of initial concentration of metal ions, amount of adsorbent, pH and contact time with natural bentonite. The maximum removal efficiency obtained for each parameter were: from effect of dose, for Pb2+ (% removal=99.9%),for Cu2+(% removal =99.99%), for Cd2+(% removal=99.95%),from effect of contact time, for Pb2+ (% removal=99.78%), for Cu2+ (% removal=99.46%), for Cd (% removal=99.95%), from effect of pH, for Pb2+ (% removal= 100%),for Cu2+ (% removal=99.66%), for Cd2+(% removal=99.06%), from effect of initial concentration, for Pb2+ (% removal=100%), for Cu2+ (% removal=82.08%), for Cd2+ (% removal =99.9%).The result obtained revealed, it was found that the removal of ions depends on initial concentration, amount of adsorbent, pH of solution and contact time. In treatment with clay, the removal of Cu (II), Cd (II) and Pb (II) ions from aqueous solution generally was very efficient for the three heavy metal ions. Except copper in acidic solution, the percent removal for all parameters were performed more than 95% was achieved by natural Bentonite. Therefore, natural Bentonite obtained from Afar region near Ledi River is an important adsorbent of heavy metal from aqueous solutions. The data obtained from adsorption experiment are fitted better with the Langmuir isotherm compared to the Freundlich model. The value of separation factor, (RL =0.322) from Langmuir equation gives an indication of favorable adsorption.