Novel adsorbent based on carbon-modified zirconia/spinel ferrite nanostructures: Evaluation for the removal of cobalt and europium radionuclides from aqueous solutions

Utilization of carbon-coated ZrO2/Mn-Mg-Zn ferrites nanostructures for the adsorption of Cs (I) and Sr (II) from the binary system: kinetic and equilibrium studies

Carbon-coated ZrO2/Mn-Mg-Zn ferrites nanostructures (CZ-FN) have been prepared as a new inorganic sorbent to remove Cs (I) and Sr (II) from a waste stream. Adsorption of Cs (I) and Sr (II) has been implemented considering different noteworthy parameters, for example, shaking time and the optimum time achieved high adsorption capacity of both ions [103 and 41 mg/g for Sr (II) and Cs (I)] was found 30 min. Also, the impact of pH values was studied; the best pH value for the adsorption process is pH 6. The adsorption saturation capacity of CZ-FN is 420.22 and 250.45 mg/g for strontium and cesium, respectively. The solubility percentage of CZ-FN was calculated utilizing diverse molarities from HNO3, HCl, and NaOH as eluents, the obtained data reveals an increase in the solubility percentage with more increase in the molarity of the eluents. The elevation in the solubility percentage follows the following order; HNO3 < HCl < NaOH. The kinetic studies were applied using the nanolinear form of different kinetic models; it was found that the adsorption process obeys the nonlinear pseudo-second-order. According to equilibrium studies, the Langmuir model has been more accurate than the Freundlich model for adsorption in the case of binary systems. The values of Di for the strontium and cesium are 10-10 m2/s, which displays the chemisorption nature of this process. The greatest values of the desorption process for the strontium and cesium are 96.87% and 94.43 by 0.3 M of HNO3. This indicated that the carbon-coated ZrO2/Mn-Mg-Zn ferrites could be regenerated and recycled to remove strontium and cesium ions from waste streams.

Adsorption and separation of Cs(I) and Ba(II) from aqueous solution using zinc ferrite-humic acid nanocomposite

Reclaimable adsorbents have an essential role in removing radionuclides from waste streams. Herein, zinc ferrite-humic acid ZFO/HA nanocomposite was synthesized for effective cesium and barium adsorption. The prepared ZFO/HA nanocomposite was analyzed using analytical techniques including XRD, FTIR, EDX, and SEM. From kinetic studies, the mechanism adsorption process follows the second model. The isotherm studies clarified that the Langmuir model fit the adsorption of both ions onto the prepared sample, and the monolayer capacities are equal to 63.33 mg/g and 42.55 mg/g for Ba(II) and Cs(I), respectively. The temperature parameter was also studied, and the adsorption reaction was spontaneous and endothermic. The maximum separation between two ions was achieved at pH 5 (αCs/Ba = 3.3).

Extraction and separation feasibility of cerium (III) and lanthanum (III) from aqueous solution using modified graphite adsorbent

Graphite (GR) and graphite/alginate (GRA) composite were synthesized utilizing the thermal annealing technique and used as a new adsorbent material for the selective separation and removal of La(III) and Ce(III) from aqueous solutions. Fourier transform infrared (FTIR) spectroscopy, thermal analysis (DTA, TGA), X-ray diffraction (XRD), surface area, porosity, and scanning electron microscope (SEM) were also used to characterize the generated material. Distinct experiments were performed to test the ability of the GRA to La(III) and Ce(III) removal, which include the effect of pH, shaken time, initial concentration of La(III), and Ce(III) at different temperatures range. After 20 min, both ions have reached equilibrium. The pseudo second-order kinetic model was chosen as one which best fits the experimental evidence and better reflects the chemical sorption process. Adsorption isotherm was studied using the Langmuir, Freundlich, and D-R models. The Langmuir model was used to better fit the results obtained. At 25 °C, Ce(III) and La(III) have maximum monolayer capacities of 200 and 83.3 mg/g, respectively. The sorption was endothermic reaction and spontaneous, as illustrated by the data of thermodynamics studies. GRA has the ability to be used as a novel lanthanide adsorbent material, especially for selective separation between Ce(III) and La(III).

Adsorption of caesium and cobalt ions on the muscovite mica clay-graphene oxide-γ-Fe2O3-Fe3O4 composite

The muscovite mica clay-graphene oxide-maghemite-magnetite (γ-Fe₂O₃-Fe₃O₄) composite was first used for the adsorption of caesium(I) and cobalt(II). The presence of clay minerals, graphene oxide, maghemite, and magnetite was detected in the prepared composite by XRD, WD-XRF, Mössbauer spectroscopy, and ATR-FTIR. The SEM and TEM results show that the composite has a layered structure with irregularly shaped pores on the surface. It was found that the adsorption of ions depends on the initial concentration, pH (except for caesium), mass of adsorbent, temperature, and contact time. The maximum adsorption capacity for Cs(I) and Co(II) was 2286 mg/g and 652 mg/g, respectively, and was obtained at concentrations (Cs(I) = 12,630 mg/L; Co(II) = 3200 mg/L), adsorbent mass of 0.01 g, pH (Cs(I) = 7; Co(II) = 5), temperature of 20 ± 1 °C, and contact time of 24 h. The high adsorption capacity of the composite could be due to a diversity of functional groups, a large number of active sites or the multilayer adsorption of caesium and cobalt ions on the surface of the composite. The Freundlich, Langmuir isotherms, and the pseudo-second-order kinetic model better describe the adsorption of these ions on the composite. The adsorption was non-spontaneous endothermic for Cs(I) and spontaneous endothermic for Co(II). The proposed mechanism of adsorption of Cs and Co ions on the composite is complex and involves electrostatic interactions and ion exchange. The ANFIS model proved to be quite effective in predicting the adsorption of Cs(I) and Co(II), as shown by the obtained values of R², MSE, SSE, and ARE.

Engineered magnetic oxides nanoparticles as efficient sorbents for wastewater remediation: a review

The rapid urbanization and industrialization is causing worldwide water pollution, calling for advanced cleaning methods. For instance, pollutant adsorption on magnetic oxides is efficient and very practical due to the easy separation from solutions by an magnetic field. Here we review the synthesis and performance of magnetic oxides such as iron oxides, spinel ferrites, and perovskite oxides for water remediation. We present structural, optical, and magnetic properties. Magnetic oxides are also promising photocatalysts for the degradation of organic pollutants. Antimicrobial activities and adsorption of heavy metals and radionucleides are also discussed.