In situ modification of activated carbons developed from a native invasive wood

JORGE DE CELIS; NORMA AMADEO; ANA LEA CUKIERMAN

JOURNAL OF HAZARDOUS MATERIALS.

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2009 vol. 161 p. 217 - 223

0304-3894

Activated carbonswere developed by phosphoric acid activation of sawdust fromProsopis ruscifoliawood, 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 (2281m2/g) and total pore volume (1.7cm3/g) than those obtained under flowing air (1638m2/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.