Coordination study of chitosan and Fe3+

Utilization of diatomite/chitosan–Fe (III) composite for the removal of anionic azo dyes from wastewater: Equilibrium, kinetics and thermodynamics

“…Moreover, the adsorption mechanism of chitosan-Fe(III) composites is still a controversial topic [18], though the chelation between dye and Fe(III) center in chitosan-Fe(III) was proved to be a main mechanism [1]. If chitosan-Fe(III) continued to be loaded on diatomite, it would be unclear how the dye is adsorbed in the composite, and the mechanism also would be require futher exploration.…”

Chitosan templated synthesis of strontium–iron–oxygen nanocrystalline system

“…Small displacement and intensity changes were significant for the bands at 1660cm -1 and 1580cm -1 due to interactions between the metal ions with acetamide and free amine chitosan groups respectively [36][37]. The Fe 3+ and Sr 2+ cations are typical hard Lewis acid and therefore more likely to bind to hard Lewis bases such as amines and hydroxyl groups present in chitosan to form metal-chitosan complex stabilized by coordination [38][39][40][41][42]. On this basis, a model of molecular structure of metal-chitosan complex is proposed as shown in Fig.…”

Degradation of four organophosphorous pesticides catalyzed by chitosan-metal coordination complexes

“…The peaks at 1595 and 1030 cm −1 disappeared in Fig. 5b, which suggested that the chelation occurred on some of the amino and primary hydroxyl sites of the glucosamine units of the chitosan structure (Hernández et al 2008;Cetinus et al 2009). …”

“…1 and 2). Hernández et al (2008) studied the coordination of Fe 3+ with chitosan and found that the coordination of polymers with the metal cation occurred from approximately pH 2 to basic pH values, with the most effective complexation pH values being from 4 to 6. The complexation was mainly through the amino group but as the metal ion possesses a hard acidity characteristic, it can also coordinate through the deprotonated -OH of C-6 or through the pair of free electrons in the O atom of the -OH from C-3.…”