title: Application of cupuassu shell as biosorbent for the removal of textile dyes from aqueous solution.
abstract: The cupuassu shell (Theobroma grandiflorum) which is a food residue was used in its natural form as biosorbent for the removal of C.I. Reactive Red 194 and C.I. Direct Blue 53 dyes from aqueous solutions. This biosorbent was characterized by infrared spectroscopy, scanning electron microscopy, and nitrogen adsorption/desorption curves. The effects of pH, biosorbent dosage and shaking time on biosorption capacities were studied. In acidic pH region (pH 2.0) the biosorption of the dyes were favorable. The contact time required to obtain the equilibrium was 8 and 18 h at 298 K, for Reactive Red 194 and Direct Blue 53, respectively. The Avrami fractionary-order kinetic model provided the best fit to experimental data compared with pseudo-first-order, pseudo-second-order and chemisorption kinetic adsorption models. The equilibrium data were fitted to Langmuir, Freundlich, Sips and Radke-Prausnitz isotherm models. For both dyes the equilibrium data were best fitted to the Sips isotherm model.
authors.affiliation: Institute of Chemistry, Federal University of Rio Grande do Sul, UFRGS, Av. Bento Gonçalves 9500, Caixa Postal 15003, CEP 91501-970, Porto Alegre, RS, Brazil.
authors.forename: Natali F
authors.initials: NF
authors.lastname: Cardoso
authors.forename: Eder C
authors.initials: EC
authors.lastname: Lima
authors.forename: Isis S
authors.initials: IS
authors.lastname: Pinto
authors.forename: Camila V
authors.initials: CV
authors.lastname: Amavisca
authors.forename: Betina
authors.initials: B
authors.lastname: Royer
authors.forename: Rodrigo B
authors.initials: RB
authors.lastname: Pinto
authors.forename: Wagner S
authors.initials: WS
authors.lastname: Alencar
authors.forename: Simone F P
authors.initials: SF
authors.lastname: Pereira
mesh_terms: D000327:Adsorption; D001938:Brazil; D004396:Coloring Agents / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D019660:Malvaceae / Q000378:metabolism*; D008855:Microscopy, Electron, Scanning; D008956:Models, Chemical; D017711:Nonlinear Dynamics; D013784:Textiles
chemical_list: D004396:Coloring Agents