Removal of Ce(IV) and Nd(III) from Acidic Solution Using Polyacrylonitrile-Encapsulated Lithium Titanium Vanadate as an Efficient Adsorbent

Evaluation of anion exchange resin for sorption of selenium (IV) from aqueous solutions

In this work, selenium (IV) ions were adsorbed from aqueous solutions by the strongly basic anion exchange resin Amberlite IRA-400. The morphology of the resin before and after Se(IV) sorption was investigated using different techniques such as energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). To determine the ideal sorption conditions, a batch approach was used to examine the variables affecting Se(IV) sorption performance, including pH, shaking time, adsorbent dosage, initial metal ion concentration, and temperature. The results showed the optimal parameters for the highest percentage of selenium (80.25%) at an initial concentration of 100.0 mg L-1, pH 3.0, the adsorbent dosage of 10.0 mg, and the shaking time of 60.0 min. According to the experimental findings, the sorption process was satisfactorily explained by the pseudo-second-order kinetic model. The maximum adsorption capacity at pH 3.0 was 18.52 mg g-1, and the adsorption rather well followed the Langmuir adsorption isotherm. Moreover, exothermic and spontaneous sorption reaction was the result of thermodynamic properties (negativity of both ΔG° and ΔH°). The adsorption phase's random distribution of the resin-solution interface is indicated by the positive value of ΔSo. Finally, the desorption study was performed using different concentrations of desorbing agents; HNO3, HCl, and sodium acetate. The results illustrated that the effective desorbing agent was 1.0 mol L-1 HNO3, with desorption efficiency reaching about 96.4%. Finally, the Amberlite IRA-400 demonstrated excellent adsorption-desorption behavior over five times, suggesting that the Amberlite IRA-400 could be an effective candidate for the sorption of Se(IV) from several metal ions that occur in fission products.

Adsorption behavior of Mo(VI) from aqueous solutions using tungstate-modified magnetic nanoparticle

A new magnetic nanoparticle modified with sodium tungstate (Mnp-Si-W) was synthesized and employed for the sorption of molybdenum from aqueous solutions. The prepared nanoparticles (Mnp-Si-W) were characterized by different advanced techniques. Different parameters that influenced the adsorption percent of Mo(VI) were investigated using a batch process. Based on a systematic investigation of the adsorption isotherms and kinetics models, Mo(VI) adsorption follows the Langmuir model and pseudo-second-order kinetics. According to the Langmuir isotherm model, the Mnp-Si-W nanoparticles exhibited a maximum adsorption capacity of 182.03 mg g-1 for Mo(VI) at pH 2.0. The effect of competing ions showed that the prepared nanoparticles have a high selectivity for the sorption of molybdenum. Moreover, the effect of some interfering anions on Mo(VI) ion sorption is found in the following order: phosphate < sulfate < chromate. Finally, the nanoparticle (Mnp-Si-W) can be successfully reused five times.

Application of Poly(caffeic acid) for the Extraction of Critical Rare Earth Elements

Poly(caffeic acid) was synthesized and utilized for the extraction and determination of rare earth elements (REEs), thorium, and uranium. Oxidative polymerization of caffeic acid, a low-cost plant-based material, in the presence of ethylenediamine produced a granular, air-stable, and cross-linked polymer. The polymer is highly oxygenated and together with the amino group from ethylenediamine efficiently coordinates and preconcentrates these critical elements from aqueous media. Extraction was dependent on solution pH, amount of sorbent, and extraction time, while the concentration and flow rate of the desorption solution governed the recovery efficiency. Removal and recovery efficiencies greater than 98 and 90%, respectively, and low levels of detection ranging from 0.1 to 2.9 ng/L were achieved. Determination of these strategic elements in the presence of potentially interfering ions as well as in complex matrices such as well water and produced water samples also was demonstrated. The capacity of poly(caffeic acid) was determined with lanthanum as a representative REE to be 161.7 mg/g, establishing the promise of poly(caffeic acid) for larger-scale extractions in addition to the ability to screen sources for the presence of REEs.