Functionalization of magnetic chitosan microparticles – Comparison of trione and trithione grafting for enhanced silver sorption and application to metal recovery from waste X-ray photographic films

Magnetic chitosan microparticles (MC) are successfully functionalized by grafting two pyrimidine derivatives (bearing either trione or trithione groups for MC-PYO and MC-PYS, respectively). The sorbents are characterized using SEM, TEM, BET, TGA, FTIR, titration, and elemental analysis. The study fo...

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Bibliographic Details
Published in:Journal of environmental chemical engineering 2022-06, Vol.10 (3), p.107939, Article 107939
Main Authors: Hamza, Mohammed F., Abdel-Rahman, Adel A.-H., Hawata, Mohamed A., El Araby, Rania, Guibal, Eric, Fouda, Amr, Wei, Yuezhou, Hamad, Nora A.
Format: Article
Language:English
Subjects:
Engineering Sciences
Silver desorption and sorbent recycling
Silver sorption isotherms and uptake kinetics
Silver valorization from spent photographic film
Sulfur-derivative for enhanced selectivity against competitor metals
Sulfur-functionalization of magnetic chitosan microparticles
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Summary:Magnetic chitosan microparticles (MC) are successfully functionalized by grafting two pyrimidine derivatives (bearing either trione or trithione groups for MC-PYO and MC-PYS, respectively). The sorbents are characterized using SEM, TEM, BET, TGA, FTIR, titration, and elemental analysis. The study focuses on the comparison of the differential effects of functionalized groups on the sorption of silver. FTIR analysis shows the contributions of N-based, carbonyl, hydroxyl for silver binding onto MC-PYO, completed by sulfur contribution in the case of MC-PYS. Maximum sorption capacities at pH 6 reach 1.9 and 2.3 mmol Ag g−1 for MC-PYO and MC-PYS, respectively. The Langmuir and the Sips equations fit sorption isotherms. The reactive groups affect the thermodynamic characteristics: endothermic for MC-PYS against exothermic for MC-PYO. The affinity of S-based soft ligand in MC-PYS for soft metals makes the sorbent selective for Ag(I). On the opposite hand, for MC-PYO the O-based functional groups readily bind hard metals (HSAB principle), meaning less selective for silver recovery (from multi-component solutions). QSAR method (quantitative structure-activity relationships) allows correlating preferentially sorption properties with the covalent index. Nitric acid solutions (0.3 M) are highly efficient for total desorption of silver from metal-loaded sorbents, but soft enough to maintain remarkable sorption and desorption performances for at least five cycles. The sorbents are successfully applied to Ag(I) recovery from acidic leachate of waste photographic films: metal removal is enhanced at pH 5.2; MC-PYS is more efficient and selective than MC-PYO at pH 2.2. [Display omitted] •Sulfur-based functionalization of magnetic chitosan particles improves Ag sorption.•Sorption capacity at pH 6 reaches 2.3 mmol Ag g−1 (equilibrium within 60 min).•Complete metal desorption with 0.3 M HNO3 and stable performance for 5 reuses.•S-based derivative more Ag selective than O-based against competitor metal cations.•Ag sorption is endothermic with S-based sorbent contrary to O-based sorbent.
ISSN:2213-3437
2213-3437
2213-2929
DOI:10.1016/j.jece.2022.107939