Continuous Flow Removal of Anionic Dyes in Water by Chitosan-Functionalized Iron Oxide Nanoparticles Incorporated in a Dextran Gel Column.

Sang Yeob Lee,Ha Eun Shim,Jung Eun Yang,Jongho Jeon,Yong Jun Choi

doi:10.3390/nano9081164

Abstract

This paper describes a novel chromatographic method for efficient removal of anionic dyes from aqueous solutions. Chitosan-coated Fe3O4 nanoparticles can easily be immobilized on a dextran gel column. Single elution of Evans Blue (EB) solution to the nanoadsorbent-incorporated columns provides high removal efficiency with a maximum adsorption capacity of 243.9 mg/g. We also investigated the influence of initial concentration and solution pH on the removal efficiency of EB. The electrostatic interaction between the adsorbent surface and negatively charged sulfate groups on EB molecules promotes the efficient adsorption of dyes. The equilibrium data matched well with the Langmuir isotherm model, which indicated monolayer dye adsorption onto the adsorbent surface. To extend the application of the current method, we performed further adsorption experiments using other anionic dyes of different colors (Cy5.5, Acid Yellow 25, Acid Green 25, and Acid Red 1). All of these molecules can efficiently be captured under continuous flow conditions, with higher removal efficiency obtained with more negatively charged dyes. These findings clearly demonstrate that the present approach is a useful method for the removal of anionic dye contaminants in aqueous media by adsorption.

Highlights

With the rapid development of various industries and the growth of manufacturing, the coinciding increase in pollution as a threat to the environment and public health has prompted considerable attention to improve the treatment of wastewater [1,2]
We successfully developed a new purification method to remove anionic dyes from aqueous solutions
The three-dimensional structure of immobilized adsorbents was characterized by the scanning electron microscopy (SEM)-EDX analysis

Summary

Introduction

With the rapid development of various industries and the growth of manufacturing, the coinciding increase in pollution as a threat to the environment and public health has prompted considerable attention to improve the treatment of wastewater [1,2]. Anionic dyes are troublesome due to their high solubility in water, various harmful effects on living organisms, and large quantities generated from many industrial sources [8,9]. These molecules are typically difficult to degrade due to their complex aromatic structures, and anionic dyes can persist as contaminants in water for long periods of time. Adsorbents based on Fe3O4 nanomaterials have been widely investigated for efficient removal of dyes in wastewater due to their low toxicity, easy and inexpensive preparation, and large surface area. The adsorbents are immersed in the wastewater and additional separation processes are required to remove the dye-adsorbed nanomaterials from the water after adsorption via an external magnetic field

Methods

Results

Conclusion