Adsorption Evaluation for the Removal of Nickel, Mercury, and Barium Ions from Single-Component and Mixtures of Aqueous Solutions by Using an Optimized Biobased Chitosan Derivative.

Efstathios V Liakos,George Z Kyzas,Dimitra A Lambropoulou,Mariza Mone,Dimitrios N Bikiaris

doi:10.3390/polym13020232

Efstathios V Liakos, George Z Kyzas + Show 3 more

Open Access

https://doi.org/10.3390/polym13020232

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Abstract

In this experimental study, the use of 5-hydroxymethyl-furfural (HMF) organic compound as a grafting agent to chitosan natural polymer (CS) was examined. One optimized chitosan derivative was synthesized, and then tested (CS-HMF), in order to uptake nickel, mercury, and barium metal ions from single- and triple-component (multi-component) aqueous solutions. The characterization of the material before and after the metal uptake was achieved by scanning electron microscopy (SEM). The ability of the adsorption of CS-HMF was tested at pH = 6. The adjusting of temperature from 25 to 65 °C caused the increase in the adsorption capacity. The equilibrium data were fitted to the models of Langmuir and Freundlich, while the data from kinetic experiments were fitted to pseudo-1st and pseudo-2nd order models. The best fitting was achieved for the Langmuir model (higher R2). The adsorption capacity for nickel, mercury, and barium removal at 25 °C (single component) was 147, 107, and 64 (mg/g), respectively. However, the total adsorption capacity for the multi-component was 204 mg/g. A thermodynamic study was also done, and the values of ΔG0, ΔH0, and ΔS0 were evaluated.

Highlights

Water pollution with toxic metals is a serious public and environmental problem in nowadays, on a worldwide scale
The evaluation of adsorption process comes from the obtained results derived from isotherms and kinetics
It can be concluded that the chitosan grafted with 5-hydroxymethyl-furfural can be used as biobased adsorbent material for the uptake of metal ions from single- and multi-component aqueous solutions, indicating its multi-functionality

Summary

Introduction

Water pollution with toxic metals is a serious public and environmental problem in nowadays, on a worldwide scale. Heavy metals tend to accumulate in receiving water bodies [6] and flora [7], because they are not selfdegradable, with result to cause various disorders and diseases. Nickel metal ions (Ni2+) can cause serious pollution of water, and this type of aqueous pollution is produced mainly from electronics, electroplating, and metal cleaning industries [11]. As it is well known, Ni2+ has high toxicity [7] and carcinogenicity, even at low concentrations [12], and in the case where it is discharged into wastewaters of industries can be a serious threat to receiving water bodies [7]. Even small amounts of Ba2+ may cause heart damage, heart rhythm changes, swelling of brains and liver, kidney damage, changes in nerve reflexes, stomach irritation, increased blood pressure, and muscle weakness [14,15]

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