title: Removal of Cr(III) from chrome tanning wastewater by adsorption using two natural carbonaceous materials: Eggshell and powdered marble.
abstract: In the present paper, eggshell and powdered marble, two carbonaceous materials, were used to remove Cr(III) ions from a real chrome tanning wastewater. The effects of initial effluent pH, adsorbent dose, contact time and temperature were studied. The maximum uptake of chromium ions was obtained at pH 5.0 with the dose 20 g L(-1) and 12 g L(-1) for eggshell and powdered marble respectively. Adsorption equilibrium was reached after 14 h contact time for eggshell and only after 30 min for powdered marble. Under these conditions, almost 99% Cr(III) was removed from chrome tanning wastewater having an initial concentration of chromium of 3.21 g L(-1). Kinetic data were satisfactorily described by a pseudo-second order chemical sorption model. The equilibrium rate constant was notably greater for powdered marble than for eggshell with 1.142·10(-3) (g mg(-1) min(-1)) and 0.041·10(-3) (g mg(-1) min(-1)) respectively. The adsorption isotherm were well described by a Langmuir model and showed that the interaction of chromium with the two adsorbents surface is a localized monolayer adsorption with a smaller energy constant for the powdered marble than for eggshell (0.020 (L mg(-1)) and 0.083 (L mg(-1)) respectively). The powdered marble was able to adsorb faster a large amount of Cr (III) in comparison to eggshell. The use of a standardized lettuce seed bioassay allowed evaluating a better effectiveness of the Cr adsorption on the powdered marble, removing up to 40% of the treated effluent toxicity than by eggshell 25%. The powdered marble could be considered as an effective, low cost carbonaceous material to be used for chromium removal from tanning wastewater.
authors.affiliation: Laboratoire d'Hydrobiologie, Ecotoxicologie et Assainissement (LHEA, URAC 33), Faculté de Sciences Semlalia, BP2390, Université Cadi Ayyad, Marrakech, Morocco; Centre National d'Etude et de Recherche sur l'Eau et l'Énergie (CNEREE), BP511, Université Cadi Ayyad, Marrakech, Morocco.
authors.forename: Saliha
authors.initials: S
authors.lastname: Elabbas
authors.affiliation: Laboratoire d'Hydrobiologie, Ecotoxicologie et Assainissement (LHEA, URAC 33), Faculté de Sciences Semlalia, BP2390, Université Cadi Ayyad, Marrakech, Morocco; Centre National d'Etude et de Recherche sur l'Eau et l'Énergie (CNEREE), BP511, Université Cadi Ayyad, Marrakech, Morocco.
authors.forename: Laila
authors.initials: L
authors.lastname: Mandi
authors.affiliation: Equipe de Physico-chimie des Matériaux, École Normale Supérieure, Université Cadi Ayyad, BP2400, 40000 Marrakech, Morocco.
authors.forename: Fatima
authors.initials: F
authors.lastname: Berrekhis
authors.affiliation: Laboratoire Réactions et Génie des Procédés, (UMR CNRS 7274), Université de Lorraine, 1 rue Grandville, 54001 Nancy cedex, France.
authors.forename: Marie Noelle
authors.initials: MN
authors.lastname: Pons
authors.affiliation: Laboratoire Réactions et Génie des Procédés, (UMR CNRS 7274), Université de Lorraine, 1 rue Grandville, 54001 Nancy cedex, France.
authors.forename: Jean Pierre
authors.initials: JP
authors.lastname: Leclerc
authors.affiliation: Laboratoire d'Hydrobiologie, Ecotoxicologie et Assainissement (LHEA, URAC 33), Faculté de Sciences Semlalia, BP2390, Université Cadi Ayyad, Marrakech, Morocco; Centre National d'Etude et de Recherche sur l'Eau et l'Énergie (CNEREE), BP511, Université Cadi Ayyad, Marrakech, Morocco. Electronic address: ouazzani@uca.ac.ma.
authors.forename: Naaila
authors.initials: N
authors.lastname: Ouazzani
mesh_terms: D000327:Adsorption; D000818:Animals; D002119:Calcium Carbonate / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry*; D002857:Chromium / Q000032:analysis* / Q000737:chemistry; D004528:Egg Shell; D006863:Hydrogen-Ion Concentration; D007477:Ions; D007700:Kinetics; D008956:Models, Chemical; D013696:Temperature; D062065:Wastewater / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
chemical_list: D002119:Calcium Carbonate; D002244:Carbon; D002857:Chromium; D007477:Ions; D062065:Wastewater
keywords: Adsorption; Chromium; Eggshell; Powdered marble; Tanning wastewater; Toxicity