Removal of Pb(II) from aqueous/acidic solutions by using bentonite as an adsorbent

The ability of bentonite clay to remove Pb(II) from aqueous solutions and from nitric acid, hydrochloric acid and perchloric acid solutions (1.0–1×10−5) has been studied at different optimized conditions of concentrations, amount of adsorbent, temperature, concentration of electrolyte and pH. Maximum adsorption of Pb(II), i.e. >98% has been achieved in aqueous solutions, while 86% is achieved from 1.0×10−5 M HCl using 0.5 g of bentonite. The adsorption decreases by increasing the concentration of electrolytes. Flame atomic absorption spectrometer was used for measuring lead concentration. Isotherm analysis of adsorption data obtained at 25°C, 30°C, 40°C and 50°C showed that the adsorption pattern of lead on bentonite followed the langmuir isotherm and freundlich isotherm, respectively. ΔHo and ΔSo were calculated from the slope and intercept of ln KD vs. I/T plots.