Adsorbent For Removal Of Uranium Research Articles

Uranium adsorption efficiency of diglycolamic acid functionalized graphitic carbon nitride adsorbent: Kinetic, isotherm, and thermodynamic studies

This study proposes the use of diglycolamic acid-functionalized graphitic carbon nitride (HDGA-gCN) as an adsorbent for uranium removal. Our experiments showed that at pH 6.0, HDGA-gCN had a high adsorption capacity of 263.2 mg g−1 and achieved equilibrium in 30 min. The adsorption isotherm was well-fitted by the Langmuir model, and the adsorption kinetics followed a pseudo-second-order equation. U(VI) adsorption on HDGA-gCN is due to electrostatic interactions between the amine, diglycolamic acid, and uranium species. The thermodynamic parameters indicate that adsorption is spontaneous and exothermic. The loaded U(VI) can be desorbed using 0.1 M Na2CO3, and HDGA-gCN exhibited an exceptional adsorption percentage for U(VI) compared to other coexisting ions. HDGA-gCN had faster kinetics, adsorption capacity, and reusability, making it suitable for U(VI) remediation.

Highly efficient sulfonated poly (ether ether ketone) (sPEEK) adsorbent for removal of uranium (VI) from aqueous solution

Sulfonated polyether ether ketone (sPEEK) polymer matrix was used as adsorbent for uranyl adsorption for first time. sPEEK showed high affinity against uranyl cations and the maximum adsorption capacity was found as 0.82 mmol/g. The maximum adsorption was achieved at pH 6. The adsorption kinetic was described by pseudo-second order model. Pore diffusion was involved in adsorption but not rate controlling step. The adsorption reaction is endothermic, and the activation energy is 85.8 kJ/mol. The desorption kinetics into 2 M HNO3, 0.1 M Na2CO3, 0.05 M EDTA and 5 % citric acid solutions were searched, and 99 % desorption was achieved when 0.05 M EDTA and 2 M HNO3 were used as leaching solution. The recovery efficiency decreased from 98 % to 88 % in 0.05 M EDTA solution and from 96 % to 86 % in 2 M HNO3 solution at the end of the fifth cycle. Uranium removal and recovery from liquid waste generated by mining and nuclear plants is of great importance. This study presents an opportunity for highly efficient removal using a low-cost and easily handled sorbent, as well as high recovery of uranyl ions with the aid of a common eluent, allowing for five cycles.

Ultrahigh efficient and selective adsorption of U(VI) with amino acids-modified magnetic chitosan biosorbents: Performance and mechanism

Exploiting eco-friendly, highly controlled preparation and convenient solid-liquid separation adsorbent to separate uranium from aquatic medium is of importance and in demand. In this study, magnetic ferroferric oxide nanoparticles synthesized through a facile hydrothermal reaction was cross-linked with chitosan. The intermediate product was subsequently chemically grafting with four amino acids such as alanine, serine, glycine or L-cysteine to produce Ala-MCS, Ser-MCS, Gly-MCS and Cys-MCS. The resultants were verified by SEM, EDS, XRD, VSM, FT-IR and XPS. Adsorption of uranium with amino acids-modified magnetic chitosans were carried out. The parameters that affected the adsorption ability, selectivity toward uranium, and reusability have been illustrated. pH 6.5 was the most beneficial for the adsorption. The saturation adsorption capacity of Ala-MCS, Ser-MCS, Gly-MCS, Cys-MCS were found as 658.88 mg/g ± 1.0 %, 616.10 ± 0.3 % mg/g, 646.38 ± 1.8 % mg/g, 653.96 ± 3.4 % mg/g and 409.15 ± 4.6 % mg/g, respectively. The adsorption process was analyzed using kinetics (pseudo-first-order, pseudo-second-order and intraparticle diffusion models) and isotherms models (Langmuir and Freundlich models). The adsorption of uranium on Ala-MCS, Ser-MCS, Gly-MCS and Cys-MCS happened on monolayer and were controlled by chemisorption. The certified high adsorption amount and efficient solid-liquid separation proved amino acids-modified magnetic chitosan are promising adsorbents for removal of uranium from wastewater.

Mesoporous Al2O3 derived from blast furnace slag as a cost-effective adsorbent for U(VI) removal from aqueous solutions

ABSTRACT This work provides an environmental approach to utilise Blast furnace slag (BFS) waste for the processing of aluminium oxide (Al2O3-BFS) as an efficient adsorbent for uranium removal from wastewater. The composition of BFS is less variable and this makes it a low cost and abundant raw material for preparing a solid base Al2O3-BFS. The silica material was initially removed and then the aluminium content was separated by precipitation with sodium hydroxide depending on pH control (pH 5.5). The raw BFS and Al2O3-BFS were characterised via various methods, such as; XRD, Zeta potential, N2 adsorption-desorption isotherm, DLS, and FT-IR. BFS exhibited the typical type III isotherm with an H3-type hysteresis loop. The curve of Al2O3-BFS exhibited the typical IV isotherms with a H2-type hysteresis loop. The BET surface and average pore sizes of the Al2O3-BFS are 137.7 m2 g-1 and 3.9 nm, respectively. Experiments and discussions were performed in terms of balance, isothermal, kinetic, and applicability. The finding provides proof of the ability of synthesised Al2O3-BFS to remove U(VI) ions from wastewater as an efficient adsorbent with a maximum sorption capacity value of 62 mg/g. The pseudo second, Langmuir and Dubinin-Radushkevich models were found suitable to explain the rate kinetics and isotherm of uranium removal. Uranium sorption on Al2O3-BFS may occur via inner-sphere complex and ion-exchange between uranium ions and HO-Al2O3-BFS groups. The higher elution efficiency of Al2O3-BFS indicates a promising adsorbent in the technology of U(VI) removal.

Biochar derived from Salvadora persica branches biomass as low-cost adsorbent for removal of uranium(VI) and thorium(IV) from water

In recent years, biochar based adsorbents have been given more attention for organic and inorganic pollutants removal. Therefore, in this study, a new low-cost biochar adsorbent derived from Salvadora persica branches (BSP) was prepared, characterized and investigated for removal of U(VI) and Th(IV) radioactive elements from water. The effects of batch adsorption conditions were studied. The maximum removal efficiencies are around 99% for each of U(VI) and Th(IV), with adsorption capacities 85.71 mg g−1 and 84.97 mg g−1 respectively. It has been found the adsorption process of U(VI) and Th(IV) is spontaneous, exothermic and follows pseudo-second-order kinetics.

Poly amidoxime functionalized carbon nanotube as an efficient adsorbent for removal of uranium from aqueous solution

The poly amidoxime functionalized carbon nanotube (PAO@CNT) was prepared, characterized, and applied for the adsorption of uranium from aqueous solutions. In this paper, a new preparation method of amidoxime-derived adsorbent was proposed to overcome the shortcomings of the rational design and synthesis of amidoxime-based adsorbents, which resulted in a low adsorption capacity. The homogeneous reaction and nano-skeleton support strategy were utilized to create amidoxime-rich polymer and its remold on the surface of carbon nanotube, composing the porous adsorbent. The results showed that PAO@CNT was an efficient adsorbent for uranium adsorption due to its abundant amidoxime functional group, and the adsorption capacity towards uranyl ions was significantly enhanced with the sequential improvement. With abundant chelating groups and porous structure (SBET = 58.169 m2/g), the adsorbent had a high adsorption capacity (~247 mg/g at pH = 4) and kinetics (equilibrium time: 120 min) for uranyl ions. The XPS and FT-IR spectra revealed the participation of N and O atoms of amidoxime groups in the adsorption of uranyl ions.

Removal of uranium from aqueous solutions using amine-functionalized magnetic platelet large-pore SBA-15

ABSTRACT A novel amine-functionalized magnetic large-pore SBA-15 obtained via in situ approach and the post-grafting method was employed as a new adsorbent for removal of uranium from aqueous solutions. Results indicated that the as-prepared adsorbent exhibited fast adsorption rates in the first hour, at the optimum pH 6. The adsorption process was fitted well to the Langmuir isothermal and the maximum adsorption capacity obtained from the Langmuir model was 395.05 mg/g for NH2-M-SBA-15 sample. The kinetics of the uranium adsorption process over NH2-M-SBA-15 was described by pseudo-second-order kinetics. In comparison with the pristine large-pore SBA-15, the adsorption performance of NH2-M-SBA-15 was improved significantly. The thermodynamic parameters revealed that the adsorption of uranium on the material was spontaneous and endothermic. Furthermore, excellent recyclability could be achieved even after four consecutive adsorption-desorption cycles.

Polypropylene nanofibre behaviour modelling for uranium adsorption by forcespinning method: artificial neural network modelling

ABSTRACT In this study, a handmade device was developed to prepare polymeric polypropylene (PP) nanofibres by forcespinning method. The characterisations of the prepared adsorbent were investigated by Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM). Then, the performance of the prepared nanofibres was investigated as an adsorbent for the removal of uranium (VI) ion from the aqueous solution. Experimental parameters such as contact time and pH were optimised. The maximum adsorption was obtained with the adsorbent weight of 0.03 g, contact time of 60 min, and pH of 4. This study showed that PP nanofibre is an efficient adsorbent for uranium removal from aqueous solution. Also, the uranium removal process was modelled by artificial neural network (ANN) for predicting capacity removal. In this method, feed-forward back-propagation learning with Levenberg-Marquardt (LM), adaptive learning rate back-propagation (GDX) and resilient back-propagation (RP) algorithms were used.

Salvadora Persica branches biomass adsorbent for removal of uranium(VI) and thorium(IV) from aqueous solution: kinetics and thermodynamics study

Adsorption isotherms of U(VI) and Th(IV) in water were obtained and removal kinetics was studied. The main functional groups on the surface of Salvadora Persica branches adsorbent were identified using a Fourier-transform infrared and the surface morphology of adsorbent was characterized by a Scanning Electron Microscope. Effects of the U(VI) and Th(IV) initial concentrations, contact time, the mass of adsorbent loading, pH of the solution were investigated at 25 ± 0.3 °C. The efficiencies with which this adsorbent removes U(VI) and Th(IV) from their solutions in water are reported. The adsorption isotherm fitted the Freundlich model. The adsorption of U(VI) and Th(IV) follows the pseudo-second order kinetic with squared correlation coefficients (R2) close to 1.0. The thermodynamic parameters (i.e. the free energy ( $$\Delta G_{\text{ads}}^{o}$$ ), the enthalpy ( $$\Delta H_{\text{ads}}^{o}$$ ) and the entropy of adsorption ( $$\Delta S_{\text{ads}}^{o}$$ ) for the adsorption of U(VI) and Th(IV) on the Salvadora Persica branches adsorbent were reported.

Amine-functionalized magnetite-silica nanoparticles as effective adsorbent for removal of uranium(VI) ions

In our studies the Fe3O4/SiO2/C3H6NH2 (MSA) adsorbent was synthesized by the green-chemistry method based on hydrolysis and condensation of tetraethoxysilane and (3-aminopropyl)triethoxysilane. The obtained material was fully characterized by a wide range of instrumental techniques and employed as an adsorbent for removal of uranium(VI) ions which is considered as a hazardous metal. It was found that the adsorption process is very fast, and equilibrium is reached after about 4 h. The data was fitted with the pseudo-1st (PFO) and pseudo-2nd order (PSO) equations. It was turned out that better fit was obtained for the PSO kinetic model. The Freundlich, Langmuir–Freundlich and Dubinin–Radushkevich isotherm equations were used to calculate the equilibrium adsorption data. The static sorption capacity was 118 mg·g−1. The energy value En = 14.8 kJ·mol−1 (293 K) calculated based on the Dubinin–Radushkevich isotherm equation indicates that chemisorption is a dominant mechanism. The obtained data show that MSA material can be used as a promising adsorbent for radioactive metals removal.

Sorption of uranium from waste effluent solutions by mesoporous carbon impregnated with trioctylamine

A new mesoporous adsorbent for uranium removal from waste effluents was prepared, characterized, and impregnated with trioctylamine. The adsorption efficiency was investigated as a function of pH, contact time, initial uranium concentration, competing ions, solid/liquid ratio, and temperature using batch sorption techniques. The maximum adsorption capacity was 21.9 mg g–1 at pH 5. The equilibrium data fit well with the Langmuir adsorption isotherm. Kinetic study showed that the process was fast and reached equilibrium within 60 min. The kinetic data fit well with the pseudo-second-order law. Thermodynamic data show that the process is spontaneous and exothermic.

Removal of uranium ions from synthetic wastewater using ZnO/Na-clinoptilolite nanocomposites

Abstract Uranium is one of the heavy metals that is found in industrial wastewater and is very toxic for human and environment. In this work, natural clinoptilolite is used as a low-cost adsorbent for uranium removal from aqueous solutions. The sodium form of clinoptilolite and ZnO/Na-clinoptilolite nanocomposite were prepared. The sample sorption capacities for uranium removal from simulated drinking water in the presence of other anions and cations were investigated. Natural zeolite and its modified forms were characterized by XRD, XRF, FTIR, TEM and BET. Batch experiments were used to determine the best adsorption conditions. The effects of various parameters such as contact time, pH, initial uranium concentration, temperature and mass sorbent on the removal efficiency of uranium ions were studied. The equilibration was attained after 2 and 6 h for the Na-clinoptilolite and ZnO/Na-clinoptilolite nanocomposite, respectively. Both adsorbents showed relatively fast adsorption. Effective removal of uranium was demonstrated at pH values of 4–8 for both forms of zeolite. Temperature had no significant effect on adsorption. The maximum removal efficiency of uranium by the ZnO/Na-clinoptilolite nanocomposite in pH=7.2 and room temperature was 98.55%. Langmuir, Freundlich and Sips models were used for describing the equilibrium isotherms for uranium uptake. The Sips model corresponded well with the experimental data. The thermodynamic parameters, such as ΔG°, ΔH° and ΔS°, have been calculated and interpreted. The pseudo-first order and pseudo-second order models were applied to describe the kinetic data. The pseudo-second order kinetic model had excellent kinetic data fitting (R2=1).

Removal of uranium(vi) from aqueous solution using iminodiacetic acid derivative functionalized SBA-15 as adsorbents

Three different functional SBA-15 were prepared by a post-grafting method using three iminodiacetic acid derivatives of ethylenediaminetriacetic acid (ED3A), diethylenetriaminetetraacetic acid (DT4A), and 1,2-cyclohexylenedinitrilotriacetic acid (CyD3A), which were used as adsorbents for removal of uranium(vi) from aqueous solution. These materials were characterized by FT-IR, NMR, TEM, nitrogen adsorption/desorption experiments, and elemental analysis. The effect of pH, ionic strength, contact time, solid-liquid ratio, initial metal ion concentration, temperature, and coexisting ions on uranium(vi) sorption behaviors of the functionalized SBA-15 was studied. Typical sorption isotherms (Langmuir and Freundlich) were determined for the sorption process, and the maximum sorption capacity was calculated. The influence of functional groups on uranium(vi) sorption was also discussed. As a result, compared with other current U(vi) sorbents (granite, kaolin, attapulgite), SBA-15-1,2-cyclohexylenedinitrilotriacetic acid (SBA-15-CyD3A) possessed good selective sorption properties, which had potential application in separation of uranium(vi).

An alternative evaluation method for accumulated dead leaves of Posidonia oceanica (L.) Delile on the beaches: removal of uranium from aqueous solutions

Posidonia oceanica (L.) Delile is an important endemic sea plant in the Mediterranean Sea. Its dead leaves are accumulated in the beaches and cause bad view and also odour in the touristical beaches. Therefore, these dead leaves accumulated on the beaches are collected and then burned in some beaches in Turkey. In the present study, the adsorption between dead leaves and uranium were studied in the aqueous solutions. The adsorption data obeyed the pseudo-second order kinetics. Among the studied isotherms, the data were well in line with the Freundlich and Dubinin-Raduschkevich models and the maximum adsorption capacities obtained from these models were found as 5.67 and 9.81 mg g−1, respectively. Negative values of Gibbs free energy showed that the adsorption was in spontaneous nature. In conclusion, the dead leaves of P. oceanica from touristic beaches might be collected and evaluated as a low-cost adsorbent for removal of uranium(VI) from aqueous solutions.

Sorption of uranium(VI) from aqueous solution onto magnesium silicate hollow spheres

The sorption of uranium(VI) from aqueous solutions was investigated using synthesized magnesium silicate hollow spheres as a novel adsorbent. Batch experiments were conducted to study the effects of initial pH, amount of adsorbent, contact time and initial U(VI) concentrations on uranium sorption efficiency. The desorbing of U(VI) and the effect of coexisting ions were also investigated. Kinetic studies showed that the sorption followed a pseudo-second-order kinetic model. The Langmuir sorption isotherm model correlates well with the uranium sorption equilibrium data for the concentration range of 25–400 mg/L. The maximum uranium sorption capacity onto magnesium silicate hollow spheres was estimated to be about 107 mg/g under the experimental conditions. Desorption of uranium was achieved using inorganic acid as the desorbing agent. The practical utility of magnesium silicate hollow spheres for U(VI) uptake was investigated with high salt concentration of intercrystalline brine. This work suggests that magnesium silicate hollow spheres can be used as a highly efficient adsorbent for removal of uranium from aqueous solutions.

Characterization and properties of zeolite as adsorbent for removal of uranium(VI) from solution in fixed bed column

A continuous fixed-bed study was carried out by using zeolite as a low-cost adsorbent for the removal of uranium(VI) ions from aqueous solution under the effect of various process parameters such as the pH the bed depth, the flow rate, the presence of salt and the initial U(VI) ion concentration. The U(VI) ion uptake by zeolite increased with initial U(VI) ion concentration and bed height, but decreased as the flow rate increased. The adsorption capacity reached a maximum at pH of 6.0. A shorter breakthrough time was observed in the presence of salt. The experimental data obtained from the breakthrough curves were analyzed using the Thomas model. The BDST model was also applied to predict the service times for other flow rates and initial concentrations. The results showed that the Thomas model was suitable for the description of the whole breakthrough curve, while the data were in good agreement with the BDST model. The columns were regenerated by eluting the bound U(VI) ions with 0.1 mol L−1 NaHCO3 solution after the adsorption studies. After desorption and regeneration with deionized water, zeolite could be reused to adsorb uranium(VI) at a comparable capacity.