Synthesis of Ethylenediaminetetraacetic Acid-Functionalized Chitosan Cryogels as Potential Sorbents of Heavy Metal Ions

Maria Marinela Lazar,Maria Valentina Dinu,Ionel Adrian Dinu

doi:10.37358/mp.21.2.5487

Abstract

An original functionalization strategy is proposed here to design chitosan (CS)-based cryogels with ethylenediaminetetraacetic acid (EDTA) moieties. Cryogels with aligned micro-sized tubular structures were further engineered through an unidirectional freezing approach. Attachment of EDTA groups onto CS chains was proved by 1H-RMN and FT-IR spectroscopy. The formation of EDTA-functionalized 3D porous CS-based cryogels was demonstrated by several methods of characterization (FTIR spectroscopy, optical microscopy, SEM, porosity measurements, swelling behavior, copper (II) retention capacity). The sorption tests pointed out the high potential of EDTA-functionalized CS-based cryogels for heavy metal ions retention.

Highlights

Biopolymers have been intensively harnessed to design more cost effective eco-friendly sorbents
The amidoxime-functionalized CS was used for removal and recovery of uranium [16,17], APCAs-functionalized CS derivatives were studied for the uptake and recovery of lead [21,25,28], nickel [22,23], cobalt [23], rare earths [24], or copper [27], while polydopamine-modified CS was efficient for removal of chromium(VI) and organic dyes [29]
The deacetylation degree (DD) value of CS was further confirmed by 1H-RMN spectroscopy taking into consideration the value of the integral of the signal at 2.05 ppm, attributed to the methyl protons in the acetyl group, respectively that of the signal at 3.18 ppm corresponding to the proton bound to the carbon atom C2 in the pyranose ring, CH-NH2 [35]

Summary

Introduction

Biopolymers have been intensively harnessed to design more cost effective eco-friendly sorbents. In most of these research studies, it has been mentioned the low-cost, the availability from natural resources, and high metal ion loading capacity as the main advantages of functionalized CS derivatives. To fully exploit their feasibility for treatment of HMIs-containing wastewaters, their regeneration in mild conditions, a fast rate of pollutant sorption/desorption, and a high level of reusability should be taken under consideration when new sorbents are planned to be developed.

Methods

Results

Conclusion