Cesium Adsorption Research Articles

Adsorption of cesium and cobalt onto dried Myriophyllum spicatum L. from radio-contaminated water: Experimental and theoretical study

In the present study, ground dry powder of Myriophyllum spicatum L. was utilized for adsorption of cobalt and cesium dissolved in water to imitate an aqueous solution contaminated with stable or radioactive elements. The dried biomass was characterized by FT-IR. The adsorption behavior was evaluated with varying various factors such as time effect, concentration of metal ion, temperature and pH-value to find out kinetic and equilibrium isotherms parameters. The experimental results indicated that about 85% of Co and more than 50% of Cs were efficiently removed from contaminated water by using the dried plant of M. spicatum L. as a function of metal concentration. Moreover, the equilibrium data were carried out by extrapolation of the “Langmuir” and “Freundlich” isotherms. Pseudo-first order, pseudo-second- order and intra-particular diffusion models were applied for the kinetic study. Based on the experimental and theoretical data obtained, it is suggested that dried biomass of M. spicatum L. could be used as an inexpensive and efficient natural adsorbent material of reasonable efficiency for the accumulation of cobalt and cesium metals from aqueous solutions.

Influence of silica fume on radioactive fluoride concentrate liquid waste solidified by magnesium potassium phosphate cement

This paper investigated the influence of silica fume on radioactive fluoride concentrate liquid waste cementation with magnesium potassium phosphate cement (MKPC). The results showed that when the silica fume mass fraction increased from 0 to 20%, the setting time and fluidity of the MKPC slurry decreased, while the 28-day compressive strength of the solidified form increased. The main hydration products were MgKPO4·6H2O and magnesium silicate hydrate (M–S–H). Silica fume had good physical adsorption of cesium, whose 42-day cumulative leaching fraction decreased from 0.083 ± 0.003 to 0.044 ± 0.002 cm. The formation of magnesium fluosilicate and its hydrate led to a decrease of fluorine leaching.

Hydrothermal-treatment desorption of cesium from clay minerals: The roles of organic acids and implications for soil decontamination

The adsorption and desorption of cesium (Cs) on clays of contaminated soil in a rhizosphere zone can be greatly affected by various biogeochemical processes, the timespans of which are usually months to years. Herein, we present several representative scenarios of the binding of Cs on diverse sites of vermiculitized biotite by controlled Cs adsorption to particles of different sizes. We investigated whether and how the fixed Cs in the different scenarios is desorbed by ambient and hydrothermal treatments with several low-molecular-weight organic acids (LMWOAs). The results showed that the sorbed Cs was discriminatively retained in the un-collapsed, partially collapsed, and thoroughly collapsed structures of vermiculites. The desorption of the sorbed Cs by hydrothermal LMWOAs extractions was easily realized in the un-collapsed structure, but was limited or minimal in the partially collapsed and thoroughly collapsed structures. The Cs desorption varied in accord with the LMWOA species applied and increased with the acid concentration, temperature, and number of treating cycles. The analysis of Cs-desorbed specimens confirmed their partial destruction and interlayer expansion, suggesting that the underlying mechanism of Cs removal by LMWOAs involves not only acid dissolution and complexation but also the accelerated weathering of clays within a short time under hydrothermal conditions. Our findings contribute novel insights into the mobility, bioavailability, and fate of Cs in contaminated soils and its removal from these soils for environmental restorations.

Magnetic zeolite synthesis for efficient removal of cesium in a lab-scale continuous treatment system

Radioactive cesium was resealed to the environment as a result of many nuclear incidents. An effective treatment system is urgently needed to safely handle radioactive cesium-contaminated waters. Based on nanoscale zerovalent iron (nZVI) and zeolite, nine adsorbents were synthesized and applied to remove cesium from aqueous solutions. Magnetic zeolite composite (Ze/Fe0) was selected as the ideal adsorbent for treating cesium contaminated waters in a lab-scale continuous treatment system (LSCTS). The optimization process of the (Ze/Fe0) composite revealed that 1:1 is the optimum mass ratio between zeolite and nZVI. Furthermore, the optimization process proved that the initial pH and temperature have no significant effect on the adsorption of cesium by (Ze/Fe0) composite and the optimum dosage of (Ze/Fe0) composite is 5 g L−1. XRD and SEM results showed that the (Ze/Fe0) composite has an irregular shape with a poor crystalline structure. Kinetic and equilibrium data were best described by pseudo second order and Freundlich isotherm models. Seawater and groundwater experiments illustrated that the removal of cesium by (Ze/Fe0) composite was inhibited due to the existence of competing cations. Eight cycles of LSCTS were performed to examine the performance of (Ze/Fe0) composite in treating continuous streams of cesium contaminated waters. In all cycles except the cycle of treating contaminated seawater, LSCTS succeed to treat continuous flows of 1 mg L−1 cesium contaminated water with 100% overall removal efficiency. For treating contaminated seawater, pre-treatment unit is required to reduce the salinity of the contaminated seawater before staring the treatment process.

Nanostructured chitosan/molecular sieve-4A an emergent material for the synergistic adsorption of radioactive major pollutants cesium and strontium

A fresh adsorbent nanostructured chitosan/molecular sieve 4A hybrid (NSC@MS-4A) was fabricated for the rapid adsorption of strontium (Sr2+) and cesium (Cs+) ions from aqueous solutions. The as-obtained NSC@MS-4A were thoroughly characterized by XRD, FE-SEM, EDS, BET, XPS and FT-IR. The physio-chemical properties and structural aspects revealed that NSC@MS-4A acquires fine surface area (72 m2/g), porous structure as well as compatible functional groups (–P–O–P and –C–O–C) for the admission of Cs+ and Sr2+ ions. The batch adsorption studies concluded that prepared adsorbent displayed a maximum adsorption of 92–94 % within 40 min. Fast adsorption of Cs+ and Sr2+ was achieved at neutral pH (6–7), ambient temperature (25−30 °C) and slow agitation speed (50−60 rpm) which could propose vast benefits such as little power utilization and uncomplicated operation. Among six types of adsorption isotherms, Freundlich isotherm showed the best fit with R2>0.997. Pseudo-second order made a better agreement as compare to other kinetic models. The thermodynamic coefficients suggested the passage of Cs+ and Sr2+ ions through the liquid solid boundary is exothermic and spontaneous. The NSC@MS-4A displayed excellent regenerability properties over five repetitive adsorption/desorption cycles, which specified that as-obtained NSC@MS-4A is a sustainable as well as efficient adsorbent for practical decontamination of radioactive liquid waste.

Efficiently remove of Cs(I) by metals hexacyanoferrate modified magnetic Fe3O4-chitosan nanoparticles

In order to remove radioactive cesium from wastewater and realize recycling of cesium meanwhile, biopolymer: chitosan functionalized Fe3O4 nanoparticles were synthesized. Chitosan covalently functionalized particles were well dispersed, superparamagnetic and had good stability. Sodium-copper hexacyanoferrate as ion exchanger modified the particles through metal coordination for cesium adsorption. The particles showed good selectivity for Cs(I) and high adsorption capacity (161.3 mg/g). And the desorption rate of Cs(I) could reach up to 99.5%. The relative adsorption capacity still remained 96.6% after the 5th reuse. The results showed the particles were promising for removal of Cs(I) from large-scale waste water.

Investigating the adsorption of cesiun ion (Cs+) on cobalt hexacyanoferrate coated magnetite nanoparticles

Co2[Fe(CN)6]/Fe3O4 nanoparticle adsorbent for ion cesium (Cs+) sorption was prepared by a chemical co-precipitation method. The magnetization of the materials makes them to be separated easyly from an aqueous solution by an external magnetic field. The ion Cs+ absorption by Co2[Fe(CN)6]/Fe3O4 nanoparticle follow the ion exchange mechanism, ion exchange capacity depends on the pH, the maximum ion exchange capacity of the material at pH = 4 is 0.40 meq (Cs+)/ g. After 15 min, about 98% of initial ion Cs+ concentration was removed from the solution, the adsorption could be described by Langmuir and Freundlich isotherms. The high adsorption capacity and good performance on other aspects, make the Co2[Fe(CN)6]/Fe3O4 nanoparticle a promissing adsorbent for the removal of ion Cs+ from water.

Studies of 137Cs absorption-desorption processes in sediments, using γ-ray spectroscopy

The description of 137Cs behavior during water to sediment transport generally involves the characterization of the sorption process in a particular hydro-geological system by certain prescribed kinetics parameters, hi the present work the kinetics of radiocesium sorption and desorption and the corresponding radiocesium distribution profiles in lake sediment cores were investigated. Radiocesium reaches rapidly (< than 5 d) at a depth which does not exceed 4 cm. The desorption of radiocesium was found to depend upon cation concentrations. Empirical laws were derived both for cesium adsorption and desorption.

Effective removal of cesium from wastewater via adsorptive filtration with potassium copper hexacyanoferrate-immobilized and polyethyleneimine-grafted graphene oxide

As an attractive alternative to radioactive cesium removal, we introduced an adsorptive filtration method using a composite membrane consisting of potassium copper hexacyanoferrate (KCuHCF) and graphene-based support. Polyethyleneimine-grafted reduced graphene oxide (PEI-rGO), used as an immobilizing matrix, was effective not only in distributing KCuHCF inside the composite with the aid of abundant amino-functionality, but also in achieving high water flux by increasing the interlayer spacing of the laminar membrane structure. Due to the rapid and selective cesium adsorption properties of KCuHCF, the fabricated membrane was found to be effective in achieving complete removal of cesium ions under a high flux (over 500 L m−2 h−1), which is difficult in a conventional membrane utilizing the molecular sieving effect. This approach offers strong potential in the field of elimination of radionuclides that require rapid and complete decontamination.

Cesium with Residual Oxygen on a Cylindrical Tungsten Polycrystal

The chemical states and changes in the work function of a heterogeneous multilevel film have been determined during the adsorption of cesium at 295 K on a cylindrical gas-phase polycrystalline tungsten coating (30 μm) of Nb–1%Zr alloy with a minimum concentration of residual oxygen using low-energy threshold electron spectroscopy and contact potential difference methods. The chemical states and the change in the work function of this film have been found during successive heating up to 1875 K.

Intensified adsorption of cesium by PVDF-g-caffeic acid/Prussian blue/polytetrafluoroethylene sandwich membranes

Intensified adsorption of cesium by PVDF-g-caffeic acid/Prussian blue/polytetrafluoroethylene sandwich membranes

Sol-gel hydrothermal synthesis of nano crystalline silicotitanate and its strontium and cesium adsorption.

Crystalline silicotitanate (CST) was synthesized via a sol-gel hydrothermal method using Na2Si2O3·9H2O and TiCl4 as silicon and titanium sources. The effects of pH, silicon concentration, hydrothermal temperature, and time on the CST synthesis were studied at a fixed molar ratio of silicon:titanium (0.98:1). Pure nano-CST crystals were synthesized at pH = 12.5, silicon concentration of 5 g L-1, 170 °C for 7 days. The average CST particle size was < 100 nm, with a Sr2+/Cs+ distribution coefficient up to 1.9 × 106 mL g-1/9.4 × 103 mL g-1 under the optimum conditions. In addition, nano-CST absorbed Sr2+/Cs+ over a wide pH range. The nano-CST also displayed a much faster equilibrium time, 4 h, as compared with previous studies. Furthermore, nano-CST adsorption of Sr2+/Cs+ followed a Langmuir adsorption model and was consistent with pseudo-second-order kinetics.

In vivo removal of radioactive cesium compound using Prussian blue-deposited iron oxide nanoparticles.

Aim: To mitigate the side effects of medical treatment by Prussian blue (PB), a well-known adsorbent for radioactive cesium (Cs), PB-deposited magnetic nanoparticles (MNPs), were prepared and analyzed on the adsorbent capacity for Cs removal. Materials & methods: The PB-deposited MNPs were prepared by photo-deposition method and investigated for their Cs adsorption properties in vitro and in vivo. The distribution of the adsorbents was also evaluated in C57BL/6 mice. Results: PB-deposited MNPs provided an improved adsorbent capacity for Cs removal and reduced toxicity to blood cells compared with those of bulk PB. Conclusion: PB-deposited MNPs could be considered as an alternative of PB-based medicine to reduce the possible hazards caused by high dose of PB intake.

Development of synthetic zeolites from bio-slag for cesium adsorption: Kinetic, isotherm and thermodynamic studies

This study reported a novel synthetic zeolite based adsorbent developed from the municipal wastewater sludge molten slag (bio-slag) through the hydrothermal modification process for removal of cesium (Cs) from simulated wastewater. The artificial zeolites were produced from the raw bio-slag which was identified by the several physicochemical experimental procedures such as the surface area analysis (the BET technique), the FESEM, the XRF and the XRD. The Cs adsorption process of modified bio-slag was exmined by the linear pseudo-first order, pseudo-second order and intra-particles diffusion models whilst the second order kinetic model confirmed a better agreement with the correlation coefficient, R2 = 0.999-1.000 for 20-400 mg/L Cs solution. The Langmuir, Freundlich and the Temkin isotherm model were investigated using the adsorption isotherm data. A satisfactory correlation coefficient value (R2= >0.980) proved that the isotherm parameters were perfectly fitted to the Langmuir and Freundlich model and the highest Cs adsorption ability of modified bio-slag were 51.02, 51.02 and 49.51 mg/g at 288, 298 and 308 K, respectively. The better agreement of adsorption data with the second order kinetic model and the Langmuir model proved the adsorption mechanism was controlled by the chemical reaction (ion-exchange). Thermodynamic studies under the different temperatures proved that the adsorption reaction was endothermic (ΔH =20.53 kJ/mol) and ΔS = 0.021 kJ/mol/K) and non-spontaneous (ΔG>0). Moreover, the modified bio-slag effectively removed Cs even in the co-existence of Na+ and K+ as competitive ions at their wide range of concentrations (upto 300 mM) although the higher concentration slightly affected the Cs adsorption.

Enhanced immobilization of Prussian blue through hydrogel formation by polymerization of acrylic acid for radioactive cesium adsorption

In this study, a hydrogel impregnated with powder activated carbon (PAC), MAA-PAC, was synthesized through the polymerization of acrylic acid (AA) and PB was immobilized using the carboxyl group of AA. In this process, an adsorbent with an enhancement of PB content and stability of immobilization was developed through the additional supply of Fe3+ ions by the layer by layer (LBL) assembly. XRD, FT-IR, SEM (EDS), TEM (EDS, mapping), and TG analyzes of the LBL and non-LBL groups were performed to confirm the change of PB content in the adsorbent as the LBL assembly was applied. The stability of PB immobilization was confirmed during the washing process after the synthesis of the adsorbent. When the LBL assembly process was applied as a PB immobilization strategy, the PB content in the adsorbent was improved and PB leakage was not observed during the washing process. The maximum adsorption (qm) for cesium in the MAA-PAC-PB LBL group that showed high PB content was 40.03 mg/g, and the adsorption isotherm was more suitable for the Langmuir model than the Freundlich model. The LBL group showed a high removal efficiency of 99.81% and a high DF value (525.88) for radioactive cesium (120 Bq/g). These results demonstrate the potential efficiency of the MAA-PAC-PB LBL group for the decontamination of radioactive cesium-contaminated water systems. Furthermore, it was verified that the LBL group of MAA-PAC-PB could be used as an adsorbent without an additional design of the existing water treatment facility. This can an economical decontamination method for removing radioactive cesium.

Highly ordered macroporous silica dioxide framework embedded with supramolecular as robust recognition agent for removal of cesium

Owning to highly mechanical strength and non-interference effectivity, silica dioxide is often explored as a stable supporter commonly with mesopore. It is known that a macroporous framework has larger mass transfer channel, possibly beneficial to adsorption process. Herein highly ordered macroporous silica dioxide framework (homogeneous pore size of 194.20 nm) was synthesized and embedded with supramolecular (CC/OMS). Cs cation adsorption onto CC/OMS was explored under different pH (presence or absence of humic acid), initial cesium concentration, shaking time, competing ions. The robust cesium uptake capacity demonstrated by a theory adsorption amount of 150.01 mg/g highlighted unique CC/OMS properties combining large mass transfer channel and superior complex capacity of supramolecular. The adsorption was well fit with Langmuir and pseudo-second-order model. Sodium and potassium at a lower concentration showed little influence on cesium adsorption. The results demonstrated that CC/OMS was an alternative material for cesium capture from acidic aqueous solution.

Adsorption of Cesium and Strontium Ions by Alkali-Treated Rice Hull Charcoal

Adsorption of Cesium and Strontium Ions by Alkali-Treated Rice Hull Charcoal

Efficient removal of Cs(I) from aqueous solution using graphene oxide

In this study, graphene oxide was synthesized, characterized and applied for cesium removal from aqueous solution. The effect of various parameters, including adsorbent dosage (0.05–0.2 g L−1), pH (3–9) and ionic strength (NaNO3 0.001–0.1 mo L−1) on adsorption capacity, as well as its adsorption kinetics, isotherms, thermodynamics and mechanism were investigated. The experimental results indicated that the adsorption of cesium (I) by the graphene oxide was an exothermic, pH- and ionic strength-dependent process. The pseudo second-order kinetic model and the Langmuir model fitted this process well, and the adsorption capacity was calculated to be 95.46 mg g−1. According to the analytical results of XRD, FTIR, and XPS, the adsorption mechanism for cesium ions should be attributed to the oxygen-containing functional groups of the graphene oxide.

Adsorption of caesium on raw Ca-bentonite in high saline solutions: Influence of concentration, mineral composition, other radionuclides and modelling

Concentration depended retention of Cs+ was analysed in alkaline and very high saline solutions (0.1–5 M), mainly NaCl but also in an artificial cement pore water (ACW), representing conditions in a potential high level nuclear waste disposal in northern Germany. Adsorbent agent was Calcigel, a raw Ca-bentonite proposed as a clay based buffer material, which was used as supplied. Batch experiments were carried out in a wide concentration range (5–250,000 nmol L−1) and subsequently, the aqueous phase was analysed via mass spectrometry with inductively coupled plasma (ICP-MS). The adsorption still depended on the Cs+ concentration in every medium and decreased with increasing electrolyte concentration, in general. In nanomolar concentration range, the retention was above 50% but dropped rapidly to only approximately 10% when ionic strength exceeded 1 M. The amount of Cs+ leached out of the clay appeared to be commensurate with electrolyte concentration. Ion exchange modelling was done using specific ion interaction theory to calculate activity coefficients. Two surface complexations were chosen to describe different adsorption sites on Calcigel. One with high selectivity for Cs+ (logKCs = 8.14) and very low capacity, such as frayed edges sites in micaceous minerals, the other one based on cationic exchange capacity of Calcigel and rather unselective for Cs+ (logKCs = 1.96). With refined selectivity constants, it was possible to describe experimental data quite perfect. However, determined values for constants differ from those found to be best for lower ionic strength. In addition, adsorption on raw Ca-bentonite was compared with that on Na-montmorillonite as a single mineral. Lower dependence on concentration was determined on single mineral in 0.1 M NaCl (79% to 53% adsorption on Na-montmorillonite, 89% to 36% on Ca-bentonite), but at higher ionic strengths the differences between the investigated clays diminished. The Cs+ adsorption on Calcigel was also analysed in presence of Eu3+, UO22+ and I−, representing potential competing ions attendant in high level nuclear waste. Here, almost no relevant influence could be detected, except at highest investigated concentration and ionic strength >1 M. At an initial concentration [Cs+]i = 250 μmol L−1, the adsorption declined remarkably in presence of other ions from approximately 10% adsorption to at least 0–5%.

Adsorption of Cesium at the External Surface of TOT Type Clay Mineral: Effect of the Interlayer Cation and the Hydrated State

The adsorption at the clay–water interface plays a critical role in many chemical, environmental, and geological processes as well as technological applications. Adsorption at the external surface ...