المستخلص: |
This paper is attempt to use activated carbons were prepared from local peanut shells for removal of lead ions (Pb2+) from aqueous solution. Four samples, variable in their activation method were selected. Two samples (PS75) and (CK) were prepared by non-conventional one-step procedures using H3PO4 and KOH Respectively .The Third sample (S800) was prepared by single –step steam activation. The last one (C33) was prepared by two step carbon dioxide. Characterization of the products was deduced from the N2- 77 K adsorption isotherms, to obtain: the total specific surface area (Sαt ), non- microporous surface area (Sαn ), total pore volume (VP(total)), and micro-meso pore volume (Voα ), (Vmeso).Carbons with Sαt = 1312-210 m2/g, Sαn =4-179 m2/g, VP(total) =0.089-0.987 cc/g, Voα=.083-.719 cc/g and Vmeso = 0.006-0.268 cc/g, were produced. Also carbon surface areas occupied by Pb2aq+ (SPbaq2+) were calculated Removal, of lead ions from aqueous solution is governed by both the chemistry (or the chemical nature) of the carbon surface as well as the diffusion through the intricate internal porosity. The pH of the carbon surface is an important variable, which controls the adsorption of Pb2+ ions at carbon-water interfaces. The data shows that, the carbon activated by KOH- and CO2- removed larger amounts of Pb2+ ions compared to steam- and H3PO4-activated carbons. The uptake of CK sample was three times that uptake of PS75 sample. This stresses, the role played by the surface chemical nature of the carbon rather than the nitrogen surface area
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