Fabrication of Silica Microspheres (HB/A@SI-MNS) for Hafnium and Zirconium Recovery from Zirconyl Leach Liquor

Abstract

This work describes the synthesis of silica microspheres using sodium silicate obtained as a byproduct in the production of Egyptian Rosetta zircon concentrate. The obtained mesoporous silica microspheres were further modified with aminopropyltriethoxy silane and 2,4-Dihydroxybenzaldehyde to produce Schiff's base silica sorbent (HB/A@Si-MNS). HB/A@Si-MNS was used for the selective extraction of hafnium from zircon mineral leach liqueur. The fabrication process and surface properties of HB/A@Si-MNS were confirmed by the means of X-ray Fluorescence (XRF), scanning electron microscop (SEM), energy depressive X-ray (EDX), Fourier-transform infrared spectroscopy (FT-IR), and elemental analysis. The uptake behavior of HB/A@Si-MNS towards Zr(IV) and Hf(IV) ions were studied under different experimental conditions. Adsorption curves indicate that the uptake of Zr(IV) and Hf(IV) on HB/A@Si-MNS is a spontaneous, endothermic monolayer system controlled by intraparticle diffusion. Elution efficiencies were found to be 94% and 98% for Zr(IV) and Hf(IV), respectively. The regenerated HB/A@SI-MNS showed uptake capacity comparable to that of fresh ones over 3 cycles. The results of the extraction of Hf(IV) than Zr(IV) from Rosetta zircon concentrate show that HB/A@SI-MNS has a preferential selectivity towards Hf(IV) than Zr(IV). Therefore, the studied material may be promising for the selective separation of Hf(IV) from Zr(IV).

RIGP-Induced Surface Modification of Cellulose for the Preparation of Amidoxime-Modified Cellulose/Graphite Oxide Composites with Enhanced Uranium Adsorption

“…It is well-known that except for surface modification, functional composites always play an important role in performance reinforcement. 18 Although crystallinityregulation of cellulose may make a contribution to the surface modification degree, the disrupted hydrogen-bond structure is not beneficial for structural stability. Combination of cellulose with a more stable material (e.g., carbon nanotubes, SiO 2 , GO) might be a feasible strategy to compensate for the weakening of the cellulose structure.…”

“…Radiation-initiated graft polymerization (RIGP) is a useful modification method of cellulose induced by the 60 Co γ-ray. , It is also established that the high-energy γ-ray can attack the hydrogen bond in the crystalline region. , However, there are barely any discussions about the effects of the RIGP method on crystallinity-regulation as well as surface modification. It is well-known that except for surface modification, functional composites always play an important role in performance reinforcement . Although crystallinity-regulation of cellulose may make a contribution to the surface modification degree, the disrupted hydrogen-bond structure is not beneficial for structural stability.…”

Preparation of Ag-Loaded Amidoxime-Functionalized Wool Fibers via Thiol-ene Click Reaction for Uranium(VI) Adsorption with Good Antibiofouling Properties

“…Recovering U­(VI) ions present in seawater at an extremely low concentration (∼3.3 μg/L) requires an energy-saving and cost-effective method. To date, reported extraction techniques have included adsorption, − ion exchange, electrochemistry, solid-phase extraction, membrane filtration, biological treatment, and photocatalysis. − Among these, adsorption has proven to be an adaptable, reliable, and environmentally friendly method . Adsorbent matrixes and binding ligands play critical roles in extracting U­(VI) ions from seawater.…”