Chitosan-based Magnetic Particles as Adsorbents for Anionic Contaminants

Melina Kloster1

Adriele A. de Almeida2

Diego Muraca2

Norma E. Marcovich1

Mirna A. Mosiewicki1,Email

1Instituto de Investigaciones en Ciencia y Tecnología de Materiales (INTEMA), Facultad de Ingeniería, Universidad Nacional de Mar del Plata – CONICET, Mar del Plata 7600, Argentina.
2Instituto de Física Gleb Wataghin (IFGW), Universidade Estadual de Campinas – UNICAMP, Campinas, São Paulo 13083-859, Brazil.

 

Abstract

An environmentally friendly nano-sized adsorbent with good adsorption capacity for ionic contaminants, that can be easily removed from treated water, was obtained. The adsorbent consists in iron oxide magnetic nanoparticles coated with chitosan, resulting in a core-shell structure. The particles were obtained by a two-step procedure that includes the synthesis of the magnetic core nanoparticles by the alkaline co-precipitation method, followed by their immersion in a dilute chitosan solution. They were characterized and the presence of the organic coating was verified using different techniques. The adsorbent properties were studied using Congo red (CR) solutions, as example of common ionic adsorbates discharged into the waste streams by textile industries. Adsorption kinetics studies at different CR concentrations and adsorption equilibrium isotherms at two pHs, are reported and modeled theoretically. The pseudo second order model was the one that best fitted the adsorption kinetics and for equilibrium studies the best fit was with either Langmuir model (pH 7) or Freundlich model (pH 3). The dye adsorption at lower pH was higher than that exhibited by neutral solutions, attributed to the increase in electrostatic attraction between negatively charged dye molecule and positively charged amine group of chitosan. Preliminary results for CR desorption are also reported. 

Chitosan-based Magnetic Particles as Adsorbents for Anionic Contaminants