Author(s)

Saint Charles Dehou, Joseph Mabingui, Ludovic Lesven, Michel Wartel, Abdel Boughriet

Chaire Unesco Sur la gestion de l’eau, Laboratoire Hydrosciences Lavoisier, Université de Bangui, Faculté des Sciences, B.P. 908, République Centrafricaine.
Université de Lille1 Laboratoire Géosystèmes Equipe Chimie Analytique et Marine, CNRS UMR 8217, BatC8, 59655 Villeneuve d’Ascq cedex, France.
Université Lille Nord de France, I.U.T de Béthune, Département de Chimie, Rue de l’Université, B.P.819, 62408 Béthune Cedex, France.

The adsorbent, iron oxy-hydroxide coated brick, was used in the present work for removal of iron(II) from aqueous solutions. The adsorption performances of this composite were significantly improved when brick pellets (as a support material) were pre-treated in a 6 M HCl solution at 90°C for 6 hours, when compared to untreated ones and those pre-washed in a 1M HCl solution at RT for 1 day. This phenomenon was attributed to larger surface areas measured for modified brick by BET, thus enabling a better FeOOH deposition. The ability of this new composite to better adsorb Fe²⁺ ions from synthetic solutions was evidenced from fixed-bed column experiments: data were compared to those obtained from raw brick and iron oxides - coated sand columns. The adsorption mechanism followed better pseudosecond-order reaction kinetics, suggesting a chemisorption process, and the rate constant increased with a temperature increase, revealing the endothermic nature of Fe(II) adsorption. Furthermore, the equilibrium data fitted the Langmuir isotherm model with a maximum monolayer sorption capacity Q_max = 0.669 mg/g and a Langmuir constant K_L = 0.659 L/mg at room temperature. The activation energy (Ea) of Fe(II) adsorption and the changes in entropy (ΔS), enthalpy (ΔH) and free energy (ΔG) of activation were determined, with values suggesting the involvement of an activated chemical adsorption and an associative mechanism.

Brick; Ferrous Ion; Iron Oxyhydroxide; Acid Activation; Adsorption; Kinetics; Activation Energy; Water Treatment

S. Charles Dehou, J. Mabingui, L. Lesven, M. Wartel and A. Boughriet, "Improvement of Fe(Ii)-Adsorption Capacity of Feooh-Coated Brick in Solutions, and Kinetics Aspects," Journal of Water Resource and Protection, Vol. 4 No. 7, 2012, pp. 464-473. doi: 10.4236/jwarp.2012.47054.