Coagulation mechanism of cellulose/metal nanohybrids through a simple one-step process and their interaction with Cr...

In this work, the coagulation mechanism of the cellulose/metal nanohybrids and the binding mode with Cr (VI) are deeply described. Nanohybrids with 3D porous networks were prepared from cellulose/Fe₂O₃-SO₃H solutions through a simple one-step coagulation process in NaCl aqueous solutions. The structure and properties of nanohybrids were characterized by SEM, EDS, XRD, FTIR, and XPS. The cellulose/metal nanohybrids have a langmuir maximum adsorption capacity of 11.46 mg/g. The dissolved metal nanoparticles could form strong hydrogen bonding with cellulose by breaking the intermolecular hydrogen bonds between the polymer molecules. The porous networks of cellulose/metal nanohybrids provided multiple adsorption sites for Cr₂O₇^2- anion through FeO^…Cr interactions. The cooperation between cellulose and Fe₂O₃-SO₃H nanoparticles makes the hybrids exhibiting a satisfactory selectivity and affinity for Cr (VI). The cellulose/metal nanohybrids selectively interacted with Cr₂O₇^2- via Fe atom from Fe₂O₃ and oxygen atom from SO₃^- groups. The Cr (VI) adsorption occurred via a two-step process, the first of them was the initial adsorption of Cr₂O₇^2- on cellulose/metal nanohybrids surface, followed by the rearrangement of Cr₂O₇^2- molecules and the consecutive growth of Cr₂O₇^2- aggregate layers.