title: Application of a new bifunctionalized chitosan derivative with zwitterionic characteristics for the adsorption of Cu(2+), Co(2+), Ni(2+), and oxyanions of Cr(6+) from aqueous solutions: Kinetic and equilibrium aspects.
abstract: This study describes the synthesis of a new chitosan derivative (C2) with zwitterionic characteristics and its use for the removal of cationic species Cu(2+), Co(2+), and Ni(2+) and anionic species of Cr(6+) in a single aqueous solution. The new adsorbent was synthesized by quaternization of the amine group of chitosan and esterification of hydroxyl groups with EDTA dianhydride. These combined reactions gave both cationic and anionic characteristics to C2 with the release of quaternary ammonium groups and carboxylic groups. The capacity of C2 to adsorb Cu(2+), Co(2+), Ni(2+), and oxyanions of Cr(6+) was evaluated in a batch process with different contact times, pH values, and initial concentrations. Adsorption isotherms were best fitted to the Langmuir and Sips models. The maximum adsorption capacities (Q(max)) of C2 for adsorption of Cu(2+), Co(2+), Ni(2+), and Cr(6+) were 0.698, 1.125, 0.725, and 1.910 mmol/g, respectively. The Δ(ads)G° values were in the range from -20 to -28 kJ/mol. These values suggest a mixed mechanism controlling adsorption. Desorption studies using an aqueous solution consisting of 0.1 mol/L HNO3 were carried out. The reusability of the recovered C2 adsorbent after desorption was also evaluated.
authors.affiliation: Group of Organic and Environmental Chemistry (GOEQ), Department of Chemistry, Institute of Biological and Exact Sciences, Federal University of Ouro Preto, Campus Universitário Morro do Cruzeiro, s/n°, Bauxita, 35400-000 Ouro Preto, Minas Gerais, Brazil.
authors.forename: Francine Tatiane Rezende
authors.initials: FT
authors.lastname: de Almeida
authors.affiliation: Department of Chemistry, Institute of Exact Sciences (ICEX), Federal University of Minas Gerais, Avenida Antônio Carlos, 6627, Pampulha, 31270-901 Belo Horizonte, Minas Gerais, Brazil; Departamento de Física e Química, Instituto de Ciências Exatas e Informática (ICEI), Pontifícia Universidade Católica de Minas Gerais, Av. Dom José Gaspar, 500, Coração Eucarístico, 30535-901 Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Bruno Christiano Silva
authors.initials: BC
authors.lastname: Ferreira
authors.affiliation: Group of Organic and Environmental Chemistry (GOEQ), Department of Chemistry, Institute of Biological and Exact Sciences, Federal University of Ouro Preto, Campus Universitário Morro do Cruzeiro, s/n°, Bauxita, 35400-000 Ouro Preto, Minas Gerais, Brazil.
authors.forename: Ana Luísa da Silva Lage
authors.initials: AL
authors.lastname: Moreira
authors.affiliation: Department of Chemistry, Institute of Exact Sciences (ICEX), Federal University of Minas Gerais, Avenida Antônio Carlos, 6627, Pampulha, 31270-901 Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Rossimiriam Pereira
authors.initials: RP
authors.lastname: de Freitas
authors.affiliation: Group of Organic and Environmental Chemistry (GOEQ), Department of Chemistry, Institute of Biological and Exact Sciences, Federal University of Ouro Preto, Campus Universitário Morro do Cruzeiro, s/n°, Bauxita, 35400-000 Ouro Preto, Minas Gerais, Brazil. Electronic address: laurent@iceb.ufop.br.
authors.forename: Laurent Frédéric
authors.initials: LF
authors.lastname: Gil
authors.affiliation: Group of Physical Organic Chemistry (GPOC), Department of Chemistry, Institute of Biological and Exact Sciences, Federal University of Ouro Preto, Campus Universitário Morro do Cruzeiro, s/n°, Bauxita, 35400-000 Ouro Preto, Minas Gerais, Brazil. Electronic address: legurgel@iceb.ufop.br.
authors.forename: Leandro Vinícius Alves
authors.initials: LV
authors.lastname: Gurgel
mesh_terms: D000327:Adsorption; D000838:Anions / Q000737:chemistry; D048271:Chitosan / Q000031:analogs & derivatives / Q000138:chemical synthesis* / Q000737:chemistry*; D002857:Chromium / Q000737:chemistry*; D003035:Cobalt / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D007700:Kinetics; D015394:Molecular Structure; D009532:Nickel / Q000737:chemistry*; D010316:Particle Size; D012996:Solutions; D013499:Surface Properties; D014867:Water / Q000737:chemistry*
chemical_list: D000838:Anions; D012996:Solutions; D014867:Water; D002857:Chromium; D003035:Cobalt; D003300:Copper; D009532:Nickel; D048271:Chitosan
keywords: Adsorption; Bifunctionalized chitosan; Chromium; Cobalt; Copper; Desorption; Nickel