Shungite/Poly(vinyl alcohol) hybrid hydrogels: An efficient adsorption material for rare earth metals in aqueous media

Abstract

Rare earth elements play a pivotal role in modern technologies, therebydriving an escalating demand for their procurement. To effectively extractthese elements from aqueous solutions, it is imperative to explore innovativesorbent materials. In this context, a hydrogel sorbent material was developedby employing poly(vinyl alcohol) (PVA) and shungite—an economical, natu-rally occurring, easily processable, and sustainable material. This was achievedthrough the freezing–thawing method, employing sodium borate as a cross-linking agent. The physicochemical characteristics of the hydrogels were deter-mined through scanning electron microscopy (SEM), transmission electronmicroscopy (TEM), thermogravimetric analysis (TGA), Fourier-transforminfrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET) analysis, Zetasi-zer analysis, and elemental analysis. The shungite-incorporated PVA hydrogelsdisplayed notable characteristics, including a substantial swelling capacity of61% and a specific surface area of 32.8 m2/g. Most significantly, these hydro-gels exhibited a remarkable affinity for La3+ions, with an uptake ratio of134 mg/g. This was followed by Nd3+,Dy3+, and Er3+ions, which displayeduptake ratios of 79, 74, and 73 mg/g, respectively.