Highly efficient recovery of vanadium from Abu Zeneima ferruginous siltstone, Southwestern Sinai, Egypt, by a novel polyimine-based chelating ligand

Abstract

To extract V⁵⁺ ions from the ferruginous siltstone in the Abu Zeneima region of Southwestern Sinai, Egypt, a chelating polyimine ligand (PVAm-Ben) was synthesized via a condensation reaction involving polyvinyl amine and α-hydroxy ketone (Benzoin). The structure of PVAm-Ben underwent comprehensive characterization employing various techniques, namely; FT-IR, ¹H-NMR, ¹³C-NMR, and GC/MS analyses. Experimental factors controlling such as pH, time, initial concentration, dosage, temperature, and stripping, were systematically optimized to enhance measurement accuracy. Under conditions of 25°C, 0.015 mol/L, and 30 minutes, PVAm-Ben/C₂H₄Cl₂ exhibited remarkable retention capacity at pH 3. Linear regression analysis results suggested the release of a mole of H⁺ during the extraction process. The stability constant (log β = 2.1882) of the PVAm-Ben/V⁵⁺ complex was determined, yielding a value of 154.24. The stoichiometry mechanism between PVAm-Ben and V⁵⁺ ions displayed a linear correlation (slope: 0.9922), signifying 1 mole of PVAm-Ben reacting with 1 mole of vanadium. The pseudo-second-order kinetic model indicated an exothermic, spontaneous, and advantageous extraction process at low temperatures. Efficient stripping of PVAm-Ben/C₂H₄Cl₂ loaded with vanadium was achieved using 0.05 M NaOH with a 99% efficiency rate. Ultimately, enhanced variables were employed to yield a V₂O₅ concentrate with a vanadium content of 55% and a purity level of 98.21%.