The necessity to recover uranium from dilute solutions (for environmental/safety and resource management) is driving research towards developing new sorbents. This study focuses on the enhancement of U(VI) sorption properties of composite algal/Polyethylenimine beads through the quaternization of the support (by reaction with glycidyltrimethylammonium chloride). The sorbent is fully characterized by FTIR, XPS for confirming the contribution of protonated amine and quaternary ammonium groups on U(VI) binding (with possible contribution of hydroxyl and carboxyl groups, depending on the pH). The sorption properties are investigated in batch with reference to pH effect (optimum value: pH 4), uptake kinetics (equilibrium: 40 min) and sorption isotherms (maximum sorption capacity: 0.86 mmol U g⁻¹). Metal desorption (with 0.5 M NaCl/0.5 M HCl) is highly efficient and the sorbent can be reused for five cycles with limited decrease in performance. The sorbent is successfully applied to the selective recovery of U(VI) from acidic leachate of uranium ore, after pre-treatment (cementation of copper, precipitation of rare earth elements with oxalate, and precipitation of iron). A pure yellow cake is obtained after precipitation of the eluate.

A zirconium silico-tungstate gel material (ZiSiW) was prepared using an inexpensive precipitating technique to be used as a sorbent. The uptake capacity of ZrSiW sorbent from uranium chloride feed solution was found to be 76 mg/g adsorbent. The Optimum adsorption process was carried out using conditions; chloride feed solution of 810 mg/L U(VI) and pH 4, solid adsorbent to chloride aqueous solutions of 1/100 and contact time of 20 minutes at 45°C. The equilibrium adsorption results were fitted well with Langmuir model, which elucidated the sorption process and provided an understanding of the sorption mechanism. The adsorption reaction was found to follow the pseudo-second-order kinetics, and the calculated adsorbate in the adsorbent at equilibrium fitted well with the experimental results. Obtained thermodynamic parameters indicated that the adsorption process was endothermic nature and the adsorption process was more favourable at high temperatures. Characterisation of the loaded adsorbent using FT-IR and EDAX analysis proved the uranium adsorption upon the ZrSiW gel.

The preparation of zirconium dioxide nanoparticles (ZrO₂-NPs) as hard ceramics was accomplished from rosette zircon concentrate through two consecutive alkaline digestion reactions. The rosette zircon concentration in the Abu Khashaba area consists mainly of zircon and monazite minerals. Using different operating conditions, the hydrothermal digestion by autoclave and the conventional alkaline fusion methods was performed upon the non-magnetic concentrate of rosette in order to complete the removal of monazite firstly and to complete the purification of zircon metal secondly. All monazite content and undesirable impurities were removed by the hydrothermal method using optimal digestion conditions such as 4 mol/L NaOH solutions, 1/6 solid to liquid, 2 h dissolving time, and a temperature of 423 K. The residual zircon (84% Zr) was subjected to complete digestion using NaOH with a zircon-to-alkali ratio of 1/1.5 and a fusion temperature of 923 K. ZrO₂-NPs were synthesized using the hydrothermal technique at 473 K for 7 h. The calcined ZrO₂-NPs were characterized by X-ray diffraction, scan electron microscope, and transmittance electron microscope. Purified silica was also obtained as a by-product from washing solutions of fused zircon.

This study reports the development and evaluation of a novel Schiff base ligand, 2-(( E )-(4-aminophenylimino)methyl)benzoic acid, for the efficient removal of lead( ii ) and cadmium( ii ) from aqueous solutions.