title: Removal of Congo red dye from aqueous solutions using a halloysite-magnetite-based composite.
abstract: Adsorption has been considered as one of the most effective methods to remove dyes from aqueous solutions due to its ease of operation, high efficiency and wide adaptability. In view of all these aspects, this study aimed to evaluate the adsorption capacity of a halloysite-magnetite-based composite in the removal of Congo red dye from aqueous solutions. The effects of stirring rate, pH, initial dye concentration and contact time were investigated. The results revealed that the adsorption kinetics followed the pseudo-second-order model, and equilibrium was well represented by the Brunauer-Emmett-Teller isotherm. The thermodynamic data showed that dye adsorption onto the composite was spontaneous and endothermic and occurred by physisorption. Finally, the composite could also be regenerated at least four times by calcination and was shown to be a promising adsorbent for the removal of this dye.
authors.affiliation: Centro de Ciências Exatas e da Tecnologia, Universidade de Caxias do Sul, Caxias do Sul, RS 95070-560, Brazil E-mail: mgiovan1@ucs.br.
authors.forename: F
authors.initials: F
authors.lastname: Ferrarini
authors.affiliation: Centro de Ciências Exatas e da Tecnologia, Universidade de Caxias do Sul, Caxias do Sul, RS 95070-560, Brazil E-mail: mgiovan1@ucs.br.
authors.forename: L R
authors.initials: LR
authors.lastname: Bonetto
authors.affiliation: Centro de Ciências Exatas e da Tecnologia, Universidade de Caxias do Sul, Caxias do Sul, RS 95070-560, Brazil E-mail: mgiovan1@ucs.br.
authors.forename: Janaina S
authors.initials: JS
authors.lastname: Crespo
authors.affiliation: Centro de Ciências Exatas e da Tecnologia, Universidade de Caxias do Sul, Caxias do Sul, RS 95070-560, Brazil E-mail: mgiovan1@ucs.br.
authors.forename: M
authors.initials: M
authors.lastname: Giovanela
mesh_terms: D000327:Adsorption; D000538:Aluminum Silicates / Q000737:chemistry*; D000077215:Clay; D004396:Coloring Agents / Q000737:chemistry*; D003224:Congo Red / Q000737:chemistry*; D052203:Ferrosoferric Oxide / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D012996:Solutions; D013816:Thermodynamics; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D000538:Aluminum Silicates; D004396:Coloring Agents; D012996:Solutions; D014874:Water Pollutants, Chemical; D003224:Congo Red; D000077215:Clay; D052203:Ferrosoferric Oxide