The development of new materials based on biopolymers (as renewable resources) is substantial for environmental challenges in the heavy metal and radionuclide ions removal contaminations. Functionalization of chitosan with sulfonic groups was achieved for improving the uranium sorption, not only from slightly acidic leachate, but also for the underground water. The prepared hydrogel based on chitosan was characterized by series of analysis tools for structure elucidation as FTIR spectroscopy, textural properties using nitrogen adsorption method, pHPZC (by pH-drift method), thermogravimetric analysis (TGA), SEM, and SEM-EDX analyses. The sorption was performed toward uranium (VI) ions for adjustment of sorption performances. The optimum sorption was performed at pH 4 (prior to the precipitation pH). The total sorption was achieved within 25 min (relatively fast kinetics) and was fitted by pseudo-first order rate equation (PFORE) and resistance to intraparticle diffusion equation (RIDE). The maximum sorption capacity was around 1.5 mmol U g−1. The sorption isotherms were fitted by Langmuir and Sips equations. Desorption was achieved using 0.3 M HCl solution and the complete desorption was performed in around 15 min of contact. The sorption desorption cycles are relatively stable during 5 cycles with limit decreasing in sorption and desorption properties (around 3 ± 0.2% and 99.8 ± 0.1%, respectively). The sorbent was used for removal of U from acid leachate solution in mining area. The sorbent showed a highly performance for U(VI) removal, which was considered as a tool material for radionuclides removing from aquatic medium.
Excess of free sulfate anions in a sulfate leach solution became an offending object for uranium recovery by using Amberlite IRA 400 anion exchange resin. This is because, not only uranium U loading efficiency is reduced significantly, but also the selectivity for the uranyl sulfate complex, [UO 2 (SO 4) 3 ] 4over ferric sulfate complex, [FeO (SO 4)]-, is reduced. The present study concerned with the feasibility of using Amberlite IRA 400 anion exchange resin for effective recovery of uranium from highly concentrated sulfate solution of Abu Hamata sandy claystone ore sample. The latter solution was found assaying 0.45 g/L and 26 g/L of U and SO 4-, respectively, together with 0.32 g/L, 0.05 g/ L, 0.008 g/L and 2.3 g/L of rare earth elements, (REEs), V, B as well as Cl-, respectively. Such solution was treated with solid CaCO 3 at different pH values ranged from 1 upto 3 for precipitating the excess free sulfate. The obtained results indicate that, U extraction efficiency has been highly improved from 48.4% up to 94.4% at pH 1.8.
The primary goal of this work is to develop a technology that allows for the recovery of metal values from waste products, thereby promoting the wise and efficient use of our nation's resources. To achieve this goal, an industrial waste of El Kriymat boiler fly Ash was used for recovering its content of vanadium, nickel and zinc. About 97, 95 and 99% respectively of these economic elements were first dissolved from boiler fly ash magnetic concentrate (after physical concentration). Leaching experiments using optimum conditions include: 180 g/L sulfuric acid concentration and 4% solid/solid proportion manganese dioxide acts as an oxidant at 80 °C. The recovery of vanadium (V) metal ions was carried out using 3% Alamine 336 in kerosene at an equilibrium pH value of 0.9. Subsequently, 15% sodium sulfide solution was used for co-precipitation of nickel and zinc metal ions in the raffinate solution at pH value of 3.5.
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