Removal of chromium(VI) from aqueous solution by activated carbons: kinetic and equilibrium studies.
The objective of this study is to assess the uptake of hexavalent chromium (Cr(VI)) from aqueous solutions onto activated carbons (AC) produced from wood. Two activated carbons are tested, a KOH-activated carbon and a commercial H3PO4-activated carbon (Acticarbone CXV). The adsorption of Cr(VI) is maximal at the lowest values of pH (pH 3) and increases with temperature for both adsorbents. The KOH-activated carbon shows higher capacity for adsorption of Cr(VI) than Acticarbone. The sorption isotherms fit the Langmuir model accurately. The adsorption reaction was found to obey a pseudo second-order rate. The activation energy and the pre-exponential factor as well as the thermodynamic functions related to adsorption reaction, DeltaS degrees , DeltaH degrees , DeltaG degrees , were determined. Nevertheless, the global reaction rate is probably controlled by the intra-particular diffusion of Cr(VI) and the mass diffusivity of Cr(VI) was evaluated.
Khezami
Lotfi
L
Université de Technologie de Compiègne, Département de Génie Chimique, Laboratoire de Génie des Procédés Industriels, UMR 6067 du CNRS-BP 20529, 60205 Compiègne, France.
Capart
Richard
R
D000327:Adsorption; D002606:Charcoal / Q000737:chemistry*; D002857:Chromium / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste / Q000517:prevention & control; D007700:Kinetics; D009584:Nitrogen / Q000737:chemistry; D009994:Osmolar Concentration; D012996:Solutions; D013696:Temperature; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000302:isolation & purification; D014877:Water Pollution, Chemical / Q000517:prevention & control
D007220:Industrial Waste; D012996:Solutions; D014874:Water Pollutants, Chemical; D014867:Water; D002857:Chromium; D002606:Charcoal; C074702:chromium hexavalent ion; D009584:Nitrogen