ADSORPTION OF PB2+ BY HEAT-TREATED AND SULFURIZED ACTIVATED CARBON

Using activated carbon (AC) and samples obtained by heat and sulfurizing treatments of the material, the adsorption of Pb2+ from aqueous solution was studied at two pH values and at three temperatures in the range 25-45-degrees-C. Adsorbents were prepared either by heat treatment of AC from 30 to 900-degrees-C in N, or H2S, or by treatment of the material first at 30-degrees-C successively in SO2 and H2S, and then at 200-degrees-C in N2. Their characterization was in terms of textural properties and surface chemistry. Techniques used were gas adsorption (N2, -196-degrees-C), mercury porosimetry, density measurements (He, 30-degrees-C), and FT-IR spectroscopy. The treatments effected on AC originated a great increase in the adsorption of Pb2+, but only when it occurred from solutions of metallic ion at unchanged pH and at 25-degrees-C. Adsorption decreased strongly by pH and temperature variations, except for AC. The adsorption rate depended on the adsorbent, pH, and temperature.