Immobilized Fe-Loaded Chitosan Film for Methyl Orange Dye Removal: Competitive Ions, Reusability, and Mechanism

Abstract

Large scale application of solid sorbent for wastewater treatment have been barred with problems associated with its difficulty of filtration and adsorbent recovery from aqueous solution. The use of a solid support could eliminate these problems and offer better adsorption ability and reusability of the adsorbent. In this study, we have fabricated Fe-loaded chitosan (Fe-CS) film immobilized onto a glass support. The prepared Fe-CS film showed greater adsorption capacity of methyl orange (MO) by 22.5% as opposed to an unmodified CS film material. The adsorption isotherms, kinetics, thermodynamics, and reusability of the prepared adsorbent were investigated in detail. The adsorption profile under kinetic conditions adopted a best-fit according to the pseudo-second-order kinetic model, while the adsorption profiles equilibrium conditions were described by both the Langmuir and Temkin isotherm models. The trend for the maximum adsorption capacity (qm) at variable temperature are listed: 97.1 (303 K), 102 (313 K) and 205 mg g−1 (323 K). The binding mechanism of MO adsorption onto the immobilized Fe-CS film was by both electrostatic attractions and chelating interactions. As well, the findings of this study showed that the immobilized Fe-CS film is an effective adsorbent that can be easily recovered from treated water and recycled for multiple adsorption–desorption processes. The properties of the immobilized Fe-CS film demonstrate its excellent ability for the removal of MO dye or any similar pollutants.