Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
581484 | Journal of Hazardous Materials | 2009 | 7 Pages |
Abstract
Activated carbons were developed by phosphoric acid activation of sawdust from Prosopis ruscifolia wood, an indigenous invasive species of degraded lands, at moderate conditions (acid/precursor ratio = 2, 450 °C, 0.5 h). For in situ modification of their characteristics, either a self-generated atmosphere or flowing air was used. The activated carbons developed in the self-generated atmosphere showed higher BET surface area (2281 m2/g) and total pore volume (1.7 cm3/g) than those obtained under flowing air (1638 m2/g and 1.3 cm3/g). Conversely, the latter possessed a higher total amount of surface acidic/polar oxygen groups (2.2 meq/g) than the former (1.5 meq/g). To evaluate their metal sorption capability, adsorption isotherms of Cu(II) ion from model solutions were determined and properly described by the Langmuir model. Maximum sorption capacity (Xm) for the air-derived carbons (Xm = 0.44 mmol/g) almost duplicated the value for those obtained in the self-generated atmosphere (Xm = 0.24 mmol/g), pointing to a predominant effect of the surface functionalities on metal sequestering behaviour. The air-derived carbons also demonstrated a superior effectiveness in removing Cd(II) ions as determined from additional assays in equilibrium conditions. Accordingly, effective phosphoric acid-activated carbons from Prosopis wood for toxic metals removal from wastewater may be developed by in situ modification of their characteristics operating under flowing air.
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Authors
J. de Celis, N.E. Amadeo, A.L. Cukierman,