Efficient Recovery of Rare Earth Elements (Pr(III) and Tm(III)) From Mining Residues Using a New Phosphorylated Hydrogel (Algal Biomass/PEI)

Abstract

With the target of recovering rare earth elements (REEs) from acidic leachates, a new functionalized hydrogel was designed, based on the phosphorylation of algal/polyethyleneimine beads. The functionalization strongly increased the sorption efficiency of the raw material for Pr(III) and Tm(III). Diverse techniques were used for characterizing this new material and correlating the sorption performances and mechanisms to the physicochemical structure of the sorbent. First, the work characterized the sorption properties from synthetic solutions with the usual procedures (study of pH effect, uptake kinetics, sorption isotherms, metal desorption and sorbent recycling, and selectivity from multi-element solutions). Optimum pH was found close to 5; sorption isotherms were fitted by the Langmuir equation (maximum sorption capacities close to 2.14 mmol Pr g−1 and 1.57 mmol Tm g−1). Fast uptake kinetics were modeled by the pseudo-second order rate equation. The sorbent was highly selective for REEs against alkali-earth and base metals. The sorbent was remarkably stable for sorption and desorption operation (using 0.2 M HCl/0.5 M CaCl2 solutions). The sorbent was successfully applied to the leachates of Egyptian ore (pug leaching) after a series of pre-treatments (precipitation steps), sorption, and elution. The selective precipitation of REEs using oxalic acid allows for the recovery of a pure REE precipitate.

Enhanced Antimicrobial, Cytotoxicity, Larvicidal, and Repellence Activities of Brown Algae, Cystoseira crinita-Mediated Green Synthesis of Magnesium Oxide Nanoparticles

“…The deconvoluted and assignment peaks of the most abundant groups or species are recorded. The C 1 s shows five splitting internal peaks, which are assigned as C (C, N, H) at 284.09 eV, C(=N, O) or C-O-C at 285.51 eV, N-C=O (amide) at 288.18 eV, and O-C=O and O-C-O at 289.53 eV, respectively ( Figure 5B ) ( Jurado-López et al, 2017 ; Hamza et al, 2019 ; He et al, 2021 ). Two internal splitting peaks were shown for the O 1s peak ( Figure 5C ) which was assigned for O (N, C, H) at 530.52 eV, and the other peak for O-C=O at 531.8 eV ( Jurado-López et al, 2017 ; Hamza et al, 2021b ; Wei et al, 2021 ).…”

“…The N 1s was splitting into five internal peaks assigned at 398.82 eV for N (C, H), and 401.04 eV for N tert , this is for polysaccharides moieties ( Lu et al, 2019 ; He et al, 2021 ), whereas the medium of the sorption and the dissolved salt source was appeared by three peaks 402.84, 404.15, and 406.54 eV for NO, NO 2 , and NO 3 , respectively ( Figure 5D ) ( Bartis et al, 2015 ).…”

Synthesis of Eco-Friendly Biopolymer, Alginate-Chitosan Composite to Adsorb the Heavy Metals, Cd(II) and Pb(II) from Contaminated Effluents

“…Adsorption/ion exchange [ 25 , 26 , 27 ] for a low concentrated solution, along with other common processes were used as membrane technologies [ 28 ], and electrolytic techniques [ 29 ]. Bio-sorption and biosorbents are easily functionalized by substitute reactive groups for increasing the loading capacity, improving kinetics, and for more efficient recovery [ 30 , 31 , 32 ]. The presence of amine and hydroxyl groups in the structure of these biopolymers facilitates the chemical modification, while physical designing can be performed by dissolving and shaping beads, fibers, and hollow fibers.…”

Leaching/Bioleaching and Recovery of Metals

“…Adsorption is one of the major strategies of metal recovery, and research works on REE uptake have been considered for this Special Issue. He et al [7] developed a new phosphorylated hydrogel (algal biomass/PEI) for the recovery of Pr(III) and Tm(III) from acidic leachates. The optimum pH was close to 5, isotherms fitted to the Langmuir equation (q max = 2.14 mmol Pr•g −1 and 1.57 mmol Tm•g −1 ), and fast sorption kinetics was represented by the pseudo-second-order rate equation.…”