Ceric-ions redox initiating technique for Zirconium and Niobium separation through graft copolymerization of natural polysaccharides

ABSTRACT

The modification of the polysaccharides as a significant route to alter the physical and chemical properties via Ceric-initiated graft copolymerization of Acrylonitrile (AN) onto Carboxymethyl cellulose (CMC) was performed under inert atmosphere using ceric ammonium nitrate (CAN) as an initiator to prepare CMC-g-PAN copolymers. In this respect, NaOH solution hydrolyzed the graft copolymer, CMC-g-PAN, to obtain hydrolyzed CMC-g-PAN hydrogel, in which the CMC-g-PAN nitrile groups were totally transformed into a combination of hydrophilic carboxamide and carboxylate groups (H-CMC-g-PAN). Pure CMC and grafted copolymers structure were identified by an analyzation of FTIR spectral data, TGA, SEM and XRD. These biodegradable and low-cost graft copolymers, with improved features could really be utilized as promising adsorbents for separation and recovery of some metal values from different media. H-CMC-g-PAN was implanted for the effective separation of Zr(IV) and Nb(V) from nitric acid solution and the batch experimental results indicate that the extraction percentage by adsorbent gradually decreased by raising the HNO₃ molarity. The calculated maximum capacity of H-CMC-g-PAN is 10.56 mg.g⁻¹ Zr(IV) and 14.07 mg.g⁻¹ Nb(V) under the used experimental conditions. Desorption investigation shows that the maximum desorption of Zr(IV) and Nb(V) was achieved with 1 M HCl, while selective stripping of Niobium was carried out using 1 M sodium hydroxide.

KEYWORDS:

• Carboxymethyl cellulose
• acrylonitrile grafting
• ceric ion
• zirconium and niobium

Acknowledgements

Authors are thankful to the Egyptian Atomic Energy Authority and the Petroleum Research Institute, Cairo, Egypt for the fruitful cooperation.

Competing interests

The authors declare that they have no competing interests.

Highlights

• H-CMC-g-PAN composite was synthesized by Ceric-initiated graft copolymerization.

• Acrylonitrile grafting onto CMC was confirmed via the low degree of crystallinity.

• Promising separation of Zr(IV) and Nb(V) with 10.56 and 14.07 mg.g⁻¹ respectively.

• Selective desorption of Nb(V) (95%) from Zr(IV) was achieved utilizing 1 M NaOH.

Additional information

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.