Preparation and characterization of ZnO/Chitosan nanocomposite for Cs(I) and Sr(II) sorption from aqueous solutions

Enhanced sorption of strontium radionuclides onto a modified molybdenum titanate composite

A study was conducted to investigate the sorption of 85Sr from aqueous solutions using a fabricated magnesium molybdenum titanate (MgMoTi) composite. The MgMoTi composites were synthesized through the co-precipitation technique and characterized using different analytical tools, including FT-IR, XRD, SEM, and EDX. The sorption studies focused on 85Sr and examined factors such as shaking time, pH, ionic strength, temperature, initial ion concentration, and saturation capacity. The results obtained from the study indicated that, under optimum sorption conditions, the saturation capacity for 85Sr onto S-4 and S-5 was determined to be 23.31 and 37.72 mg g-1, respectively. The sorption of 85Sr exhibited dependence on pH and ionic strength. The kinetics of the sorption process followed the pseudo-2nd-order model, while the thermodynamics revealed an endothermic and spontaneous nature. Desorption studies revealed that 0.1 M HCl was the most effective eluent for the complete recovery of 85Sr. Furthermore, the recycling results demonstrated the excellent recyclability of MgMoTi, suggesting its potential application as a sorbent for the removal of 85Sr from aqueous solutions. Overall, the study highlights MgMoTi as a promising composite with practical utility in the sorption of 85Sr from aqueous solutions.

Sorption behavior of strontium and europium ions from aqueous solutions using fabricated inorganic sorbent based on talc

Sorption of Sr(II) and Eu(III) from aqueous solutions was studied using tin molybdate talc sorbent synthesized by the precipitation technique. The synthesized sorbent was characterized using different analytical tools, such as; FT-IR, SEM, XRD, XRF, TGA, and DTA. The sorption studies applied to Sr(II) and Eu(III) include the effects of shaking time, pH, concentrations, and saturation capacity. The sorption of Sr(II) and Eu(III) depends on pH, reaction kinetics obey the pseudo-2nd-order model, and the Langmuir model is better suited for the sorption isotherm. The thermodynamic parameters reflect an endothermic and spontaneous sorption process. Desorption studies showed that 0.1 M HCl was the best desorbing agent for the complete recovery of Sr(II) (96.8%) and Eu(III) (92.9%). Finally, the obtained data illustrates that the synthesized sorbent can be applied and used as an efficient sorbent for the sorption of Sr(II) and Eu(III) from aqueous solutions and can be used as a promising sorbent to remove Sr(II) and Eu(III).

Efficient uptake of 85Sr and 60Co using fabricated inorganic sorbent for reducing radiation doses of simulated low-level waste

The present study investigated the sorption behavior of 85Sr and 60Co radionuclides from aqueous solutions onto tin molybdate (SnMo) sorbent. SnMo has been synthesized using the precipitation method and was characterized using four analytical techniques including FT-IR, XRD, SEM, and XRF. The sorption studies applied on 85Sr and 60Co include the effect of shaking time, pH, concentration, and saturation capacity. The experimental data revealed that the sorption process was carried out after equilibrium time (180 min). The saturation capacity for 85Sr and 60Co is measured to be 58.1 and 52.2 mg g-1, respectively. The sorption behavior of studied radionuclides is dependent on pH values. Sorption kinetic better fit with the pseudo-second-order model. Furthermore, the sorption isotherm is better represented by the model proposed by Langmuir. The results of the desorption investigations indicated that the most effective eluents for achieving full recovery of investigated radionuclides were identified. Finally, the recycling results demonstrate the suitability of SnMo for affected sorbing of 85Sr and 60Co from aqueous solutions. All the obtained data clarify that the SnMo sorbent is an effective means of removing 85Sr and 60Co from liquid waste.

Dielectric Barrier Discharge Plasma Processing and Sr-Doped ZnO/CNT Photocatalyst Decoration of Cotton Fabrics for Self-Cleaning Application

Nonthermal plasma processing is a chemical-free and environmentally friendly technique to enhance the self-cleaning activity of nanoparticle-coated cotton fabrics. In this research, Sr-doped ZnO/carbon nanotube (CNT) photocatalysts, namely, S10ZC2, S15ZC2, and S20ZC2 with different Sr doping concentrations, were synthesized using the sol-gel method and coated on plasma-functionalized fabric to perform the self-cleaning tests. The fabrics were treated with dielectric barrier discharge plasma in an open environment for 3 min to achieve a stable coating of nanoparticles. The energy band gap of the photocatalyst decreased with an increase in the level of Sr doping. The band gap of S10ZC2, S15ZC2, and S20ZC2 photocatalysts was estimated to be 2.85, 2.78, and 2.5 eV, respectively. The hexagonal wurtzite structure of ZnO was observed on the fabric surface composited with CNTs and Sr. The S20ZC2 photocatalyst showed better homogeneity and photocatalytic response on the fabric when compared with S10ZC2- and S15ZC2-coated fabrics. The S20ZC2 photocatalyst showed 89% dye degradation efficiency after 4 h of light exposure in methylene blue solution, followed by S15ZC2 (84%) and S10ZC2 (80%) photocatalysts.

Performance of molybdenum vanadate loaded on bentonite for retention of cesium-134 from aqueous solutions

This article studied the sorption behavior of Cs(I) ions from aqueous solutions onto molybdenum vanadate@bentonite (MoV@bentonite) composite. MoV@bentonite has been fabricated using the precipitation method and was characterized by different analytical tools including, FT-IR, XRD, and SEM attached with an EDX unit. The sorption studies applied on Cs(I) ions include the effect of contact time, pH, initial metal concentrations, ionic strength, desorption, and recycling. The experimental results revealed that in the adsorption process carried out after equilibrium time (300 min), saturation capacity has a value of 26.72 mg·g^-1 and the sorption of Cs(I) ions is dependent on pH values and ionic strength. Sorption kinetic better fit with the pseudo-second-order model; sorption isotherms apply to Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherm models. Data of thermodynamic parameters indicate that sorption is spontaneous and endothermic. Recycling experiments show that MoV@bentonite could be used for 7 cycles and the best eluant for the recovery of Cs(I) ions is 0.1 M HCl (76.9%). All the obtained data clarify that MoV@bentonite is considered a promising sorbent for the sorption of Cs(I) ions from aqueous solutions.

Zirconium preconcentration from zircon raffinate using gamma radiation-induced polymerization of reduced graphene oxide composite

Zirconium is commonly used as a cladding material for nuclear reactors. The purity of the zirconium material seeks to control reactor efficiency. A novel composite of reduced graphene oxide-grafted polyacrylic acid, malic acid, and trioctylamine (rGO-g-PAA-MA/TOA) was prepared using in situ radical polymerization with gamma radiation at a dose of 25 KGy from a ⁶⁰Co cell to preconcentrate zirconium Zr(IV) from zircon raffinate. Five distinct rGO-g-PAA-MA/TOA composite compositions were created and evaluated. The best composite composition was 62.95% acrylic acid, 15.8% malic acid, and 15.8% trioctylamine. After 60 min, the sorption reaction reached equilibrium at pH 0.35 and 20 °C. The pseudo n^th order indicated that the order of the sorption reaction was 1.8476. The Elovich model and Dubinin-Radushkevich model controlled the kinetic mechanism and adsorption isotherm of the sorption reaction, respectively; based on estimated regression plots and quantitatively with three different error functions: coefficient of determination (R²), chi-square statistic (χ²), and corrected Akaike information (AIC_c). The adsorption capacity of rGO-g-PAA-MA/TOA was 75.06 mg g^-1. Exothermic reaction and spontaneous sorption took place. Using 2 M H₂SO₄, 98% of the zirconium was efficiently desorbed. The separation of contaminated Ti(IV) from desorbed Zr(IV) by raising pH to 2.5 through hydrolysis and ZrO₂ formation.

Sorption of cesium and gadolinium ions onto zirconium silico antimonate sorbent from aqueous solutions

Using a batch equilibrium technique, the sorption of ¹³⁷Cs and ¹⁵³Gd onto synthesized zirconium silico antimonate (ZrSiSb) sorbent was examined. The new sorbent was prepared by precipitation technique and characterized by diverse analytical tools. The influence of shaking time, pH, metal ion concentrations, temperature, and a real sample was carried out. The data indicate that ZrSiSb has a very fast equilibrium time (30 min). The distribution coefficient values as a function of pH have sequence order; Cs(I) > Gd(III). The reaction kinetic obeys the pseudo-2^nd-order model. The saturation capacity is 69.8 and 27.2 mg/g for Cs(I) and Gd(III), respectively. Equilibrium data were analyzed by various sorption isotherm models. Desorption studies showed that the best eluents for complete recovery (about 99%) of the selected ions are KCl for Cs(I) and CaCl₂ for Gd(III). The sorption effectiveness of the new ZrSiSb to remove ¹³⁷Cs and ¹⁵³Gd from real low-level radioactive waste was examined. The results obtained showed that the prepared new composite can be applied as a hoped sorbent material to get rid of these radionuclides from different wastewaters.

Inclusion, occlusion and adsorption of rare earth elements from chloride media onto barite-gypsum composite

In this study, a synthetic BaSO4·CaSO4 composite was prepared by co-precipitation technique, characterised and examined for REE sorption. The sorption parameters were; pH = 4, equilibrium time = 20 min, temperature = 303 K, and REE liquor volume to composite mass ratio of 0.2:1 L g−1. The sorption reaction was controlled by pseudo 2nd order kinetic mechanism and Langmuir adsorption isotherm with an adsorption capacity of 168.63 mg g−1. 90.14% of REE (III) was desorbed using 1 mol L−1 HNO3. The process was endothermic and spontaneous. Accordingly, 1:1 barite-gypsum (natural ingredient for BaSO4·CaSO4), with 136 mg g−1 loading capacity, was used for REEs extraction.

High efficient removal of lead(II) and cadmium(II) ions from multi-component aqueous solutions using polyacrylic acid acrylonitrile talc nanocomposite

This study is interested in the removal of Pb(II), Cd(II), Co(II), Zn(II), and Sr(II) onto polyacrylic acid acrylonitrile talc P(AA-AN)-talc nanocomposite. P(AA-AN)-talc was fabricated using γ-irradiation-initiated polymerization at 50 kGy. Different analytical tools were used to investigate the functional groups, morphology, particle size, and structure of this composite. The ability of P(AA-AN)-talc to capture (Pb²⁺, Cd²⁺, Co²⁺, Zn²⁺, and Sr²⁺) as multi-component aqueous solutions was performed by a batch method. Saturation capacity and the effect of (agitating time, pH, initial metal concentrations, and temperature) were investigated. The distribution coefficients at different pHs have order: Pb²⁺  > Cd²⁺  > Co²⁺  > Zn²⁺  > Sr²⁺. The saturation capacity decreases by increasing heating temperatures. Reaction kinetic obeys the pseudo-second-order model. Sorption isotherms are more relevant to a Langmuir isotherm, and the monolayer sorption capacity is closed to saturation capacity. Thermodynamic parameters (∆G˚, ∆H˚, and ∆S˚) were endothermic and spontaneous. P(AA-AN)-talc is used for loading and recovery of studied cations in the column system. The study confirms that P(AA-AN)-talc is a promised composite for the sorption of the studied ions from aqueous solutions and should be considered as potential material for decontaminating these ions.

Sorption of 60Co(II) from aqueous solutions onto biosynthesized zinc oxide nanocomposites

Nano ZnO is biosynthesized using Lactobcillus sp. Poly Acrylic acid-co-Acrylonitrile/ZnO, PAACAN/ZnO, and poly Acrylic acid-co-Maleic acid/ZnO, PAACMA/ZnO, nancomposites were synthesized using 60Co γ-rays. PAACAN/ZnO and PAACMA/ZnO nanocomposites were characterized and used as sorbents for 60Co(II) radionuclide. The monolayer adsorption capacities of 60Co(II) onto PAACMA/ZnO and PAACAN/ZnO are 18.235, 7.105 mgg−1, respectively at pH 4.5 and 20 °C. The sorption reaction has a pseudo 2nd order mechanism. 0.1 M EDTA could be used as an eluent for desorption. The desorption efficiencies of 60Co(II) from PAACAN/ZnO and PAACMA/ZnO were 67.51 and 84.85%, respectively. The sorption process is endothermic and spontaneous.