Removal of methyl violet 2B dye from aqueous solution using a magnetic composite as an adsorbent

L.R. Bonetto (1) , F Ferrarini (1) , C. de Marco (1) , J.S. Crespo (1) , Régis Guégan (2) , M Giovanela (1)

1 Centro de Ciências Exatas e Tecnologia
2 ISTO - Institut des Sciences de la Terre d'Orléans - UMR7327

Despite the important role of the textile industry in the global economy, its effluents generate deepconcern with regard to treatment and disposal. Adsorption is a promising technique for the removal oftextile color effluent at relatively low cost and with satisfactory efficiency. This study aimed to evaluatethe adsorption capacity of a halloysite-magnetite-based composite in the removal of methyl violet 2Bcationic dye. After preparation, the obtained composite was characterized by applying several instrumen-tal techniques, including X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopyand determination of pH at the point of zero charge. The influences of stirring rate, adsorbent mass, pH,initial concentration of dye and contact time on the adsorption process were also studied. The adsorptioncapacity of the composite was then investigated in a temperature-controlled batch system. The experi-mental results showed that the adsorption kinetics were better described using a pseudo-second-ordermodel. Regarding the adsorption equilibrium, the experimental results suggest that both the Langmuirand Freundlich models were applicable. The thermodynamic data showed that dye adsorption onto thecomposite was spontaneous and endothermic and occurred by physisorption. The employed compositecould also be regenerated at least four times using a 1.0 mol L−1solution of NaOH as an eluent and wasshown to be a promising adsorbent for the removal of cationic dyes.

Mots clés: Thermodynamics; Adsorption; Kinetics; Halloysite-magnetite-based composite; Methyl violet 2B

Domaines: Planète et Univers [physics]; Interfaces continentales, environnement

L.R. Bonetto, F Ferrarini, C. de Marco, J.S. Crespo, Régis Guégan, et al.. Removal of methyl violet 2B dye from aqueous solution using a magnetic composite as an adsorbent. Journal of Water Process Engineering, 2015, 6, pp.11-20. ⟨10.1016/j.jwpe.2015.02.006⟩. ⟨insu-01130235⟩