Fixation of Cesium, Cobalt, Lead and Copper onto Natural and Activated Bentonite

In this study an abundant and a low cost naturally occurring bentonite (n-bentonite) and activated bentonite have been considered for the removal of cesium, cobalt, lead and copper from liquid wastes. Na-bentonite, K-bentonite was prepared by treatment with 5 % NaOH and 5% KOH for 6 hours at 70 degree C while T-bentonite was heated up to 850 degree C for 30 min. The chemical composition of n-bentonite and activated bentonite was determined by XRF technique. The study has been carried out batch wise and the influence of physico-chemical key parameters such as the contact time, the temperature, the adsorbate concentration, the adsorbent dosage, the solution ph have been considered. The maximum metal ions uptake were obtained at 60 min. contact time and ph 3 for Pb(II) and Cu(II) , ph 2.5 for Co(II) and Cs(I). The maximum metal ion uptake values for Pb(II), Cu(II), Co(II) and Cs(I) using n-bentonite were 85.2, 83.4, 81.1 and 80.5 wt.%, respectively, while the maximum uptake for the same metal ions using Na-bentonite were 98.7, 96, 93.5 and 90.2 wt. %, respectively. It was found that the percent removal of the metal ions studied were seriated in the following order: Na-bentonite > K-bentonite > T-bentonite > n-bentonite. The Langmuir kinetic model was employed and well represented the experimental data