Cs Adsorption Capacity Research Articles

Layered ammonium vanadate nanobelt as efficient adsorbents for removal of Sr2+ and Cs+ from contaminated water

In this study, a layered ammonium vanadate (NH4V4O10) nanobelt adsorbent was synthesized by a facile hydrothermal method to remove Sr2+ and Cs+ from contaminated water. The NH4V4O10 nanobelt was texturally and morphologically characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Raman, thermogravimetric differential thermal analyzer (TG-DSC), Brunauer– Emmett–Teller (BET), and X-ray photoelectron spectroscopy (XPS) both before and after adsorbing Sr2+ and Cs+. The results showed that the NH4V4O10 nanobelt exhibited the optimal morphological structure with a 2:1 ratio of NH4VO3:dipropylamine. In the lattice of the adsorbent, the horizontal distance between oxygen atoms was 0.55 nm, the vertical distance between vanadium was 0.35 nm, and the layer distance of the adsorbent was 0.931 nm. The structure characterization indicated the VO6 octahedron formed a basic framework through sharing connected vertices. Adsorption mechanism studies indicated that ion exchange was the main adsorption mechanism for removing Sr2+ and Cs+. Batch experiments revealed that the adsorption capacity for Sr2+ was 192.52 mg/g under a pH of 2. Similarly, the adsorption capacity for Cs+ was 251.09 mg/g when the pH was 5. The adsorption kinetics and adsorption isotherms data were in accordance with the pseudo-second-order kinetic model and Langmuir model, respectively. Adsorption isotherms results also indicated that the adsorption of Sr2+ and Cs+ was endothermic (ΔHSr0 = 3.6 kJ/mol, ΔHCs0 = 29.1 kJ/mol) and increased entropy (ΔSSr0 = 29.15 J/molK, ΔSCs0 = 160.38 J/molK). Finally, the structure of the adsorbent, the adsorption performance and mechanism, and the interpretation of selective adsorption were also calculated by DFT method at the molecular level and the results were consistent with the experimental data.

Adsorption behavior of iodide ion by silver-doped zeolite 4A in LiCl-KCl molten salt

In this study, the porous material zeolite with cage-like structure was modified to prepare silver-doped zeolite 4A (abbreviated as Ag@4A) using ion exchange method, with a silver loading of 34.2 wt% and a specific surface area of ​​23.62 m2/g. The adsorption performance of Ag@4A for anionic iodine in LiCl-KCl molten salt system was investigated through static adsorption experiments. The modified adsorbents and experimental samples were analyzed by XRD, SEM, ICP-OES and other methods. At 550 °C, compared with the unmodified zeolite 4A, adsorption capacity of 34 mg/g of iodine, the maximum adsorption capacity of Ag@4A for iodine ions was up to 160 mg/g. When Cs+ existed in the system, the maximum adsorption capacity of Ag@4A for iodide ions was about 64 mg/g; when Cs+ and Sr2+ coexisted, the maximum adsorption capacity of Ag@4A for iodide ions decreased to 103 mg/g. Ag@4A also showed a certain adsorption capacity for Cs+ and Sr2+. These results indicated that the Ag@4A has potential application for the removal of iodide ions and other cations in chloride molten salt.

프러시안블루 및 유기점토 함유 하이드로겔 비드의 세슘 및 요오드 제거 특성

Radiation severely damages the environment in the event of a radioactive explosion, such as the one that occurred at the Fukushima nuclear power plant in 2011. Radioactive cesium and radioactive iodine, in particular, are known to be the main causes of environmental pollution. This study aimed to develop a composite adsorbent that can remove Cs⁺ and I^- from a waterbody simultaneously. Prussian blue (PB) and organoclay are known to be effective in adsorbing cesium and iodide, respectively. Therefore, an organoclay-PB in alginate (OPAL) bead with layer-by-layer synthesis was developed. Fourier-transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric (TG) analyses were used to determine if organoclay and PB were synthesized in the OPAL bead. According to the isothermal adsorption experimental results, the maximum adsorption capacity of Cs⁺ and I^- obtained using the Langmuir isotherm model was 26.4 and 3.39 mg/g, respectively. The adsorption rate of Cs⁺ on the OPAL bead was found to be fast in a dual solute adsorption system. The adsorption capacity of the single and dual solute adsorption systems for Cs⁺ ions increased rapidly up to 1 h, and the adsorption equilibrium was attained 3 h later. The dual solute adsorption system had a higher adsorption rate for I- ions. This demonstrates that the developed composite adsorbent can be used to remove Cs⁺ and I^- from water simultaneously.

Electrochemical Removal of Cesium Ions via Capacitive Deionization Using an Ion-Exchange Layer Coated on a Carbon Electrode

This study was conducted to evaluate the feasibility of using electrosorption to remove cesium (Cs+) ions from aqueous solutions using the membrane capacitive deionization (MCDI) process. The electrochemical properties were analyzed using cyclic voltammetry (CV) and impedance spectroscopy (EIS). The activated carbon electrode coated by a polymer layer showed higher specific adsorption capacity (SAC) and removal efficiency of Cs+ than the AC electrode. The effects of potential, flow rate, initial Cs+ concentration, and pH values were investigated to optimize the electrosorption performance. The electrosorption capacity increased with an increase in the applied potential and the concentration of Cs+ in the influent water. The pH value is an important parameter on electrosorption performance. The removal of Cs+ ions was affected by the pH of the influent water because H+ ions acted as competing ions during the electrosorption process. Cs+ was preferentially adsorbed to the electrode in the early stages of adsorption but was later replaced by H+. A higher presence of H+ ions could reduce the adsorption capacity of Cs+ ions. The ion-exchange layer coated AC electrode was shown to be favorable for the removal of Cs+, despite the limited electrosorption ability in a highly acidic solution.

Stabilization of Prussian blue analogues using clay minerals for selective removal of cesium

Numerous Prussian blue analogues (PBAs) and their application in cesium elimination have been conducted. However, those were practically impossible to use in alkaline solution and seawater, due to the low stabilization of PBAs in alkaline solution and quickly decompose to create toxic cyanide contamination. In this research, potassium zinc hexacyanoferrate (PZH), one kind of PBAs was chosen, and the stability of PZH in the alkaline solution was remedied by incorporating magnetic rectorite (MR) and evaluated by XRD, XPS and cyanide analysis. Effect of pH value and the water systems on the crystalline and chemical stability were studied. The adsorption performance for Cs+ in high pH solution and the biological toxicity of the PZH/MR composite were also evaluated. The composite material exhibits significant adsorption capacity for Cs+ ions (215.128 mg/g, 293 K, increased over 20% than pristine PZH) and low cytotoxicity in human hepatic cells (HepG2 cells), indicating its potential application Cs+ adsorption in waste-water and Cs+ decorporation from body. The stability and safety mechanism in a wide pH range (from 2 to 11) were explained. The stabilization method on PBAs is an advanced yet and effective feasible mean with applications for internal and external cesium remediation. This research opens up a wide range of novel applications for PB-based adsorbents or decorporation, particularly in the field of the cesium remediation in high pH value.

Removal of Cesium from Radioactive Waste Liquids Using Geomaterials

In this study, we investigated the removal of Cs from aqueous solutions using geomaterials. Adsorption was chosen as an effective method to develop for the removal of Cs from radioactive waste liquids. Geomaterials, including fly ash and slag as raw materials, were prepared as adsorbents using an alkali activator. The materials were characterized by X-ray diffraction (XRD); scanning electron microscopy with energy dispersive spectrometer (SEM-EDS); and BET surface area, pore volume, and pore size analysis. The effects of various parameters, such as pH, contact time, and adsorbent dosage on the adsorption of the Cs were studied. The partition coefficient (PC) as well as the adsorption capacity were evaluated to assess the true performance of the adsorbent in this work. The fly ash-based geomaterials showed a maximum Cs adsorption capacity of 89.32 mg·g−1 and a high PC of 31.02 mg·g−1·mM−1 for the Cs under our experimental conditions. From this work, this method can be regarded being practical for use as a potential adsorbent for treating Cs in wastewater. Furthermore, the immobilization of Cs in geomaterials was explored from a chemical perspective. In conclusion, fly ash-based geomaterials may be a promising option for the treatment and disposal of nuclear-contaminated waste.

Electrochemical Sensing and Removal of Cesium from Water Using Prussian Blue Nanoparticle-Modified Screen-Printed Electrodes

Selective screening followed by the sensing of cesium radionuclides from contaminated water is a challenging technical issue. In this study, the adsorption functionality of Prussian blue (PB) nanoparticles was utilized for the detection and efficient removal of cesium cations. An efficient PB nanoparticle-modified screen-printed electrode (SPE) in the three-electrode configuration was developed for the electrochemical sensing and removal of Cs+. PB nanoparticles inks were obtained using a facile two-step process that was previously described as suitable for dispensing over freshly prepared screen-printed electrodes. The PB nanoparticle-modified SPE induced a cesium adsorption-dependent chronoamperometric signal based on ion exchange as a function of cesium concentration. This ion exchange, which is reversible and rapid, is associated with electron transfer in the PB nanoparticle-modified SPE. Using this electrochemical adsorption system (EAS) based on chronoamperometry, the maximum adsorption capacity (Qmax) of Cs+ ions in the PB nanoparticle-modified SPE reached up to 325 ± 1 mg·g−1 in a 50 ± 0.5 μM Cs+ solution, with a distribution coefficient (Kd) of 580 ± 5 L·g−1 for Cs+ removal. The cesium concentration-dependent adsorption of PB nanoparticles was also demonstrated by fluorescence spectroscopy based on fluorescence quenching of PB nanoparticles as a function of cesium concentration using a standard fluorophore like fluorescein in a manner analogous to that previously reported for As(III).

Upcycling of steel slag for manufacture of Prussian-blue-encapsulated pectin beads and its use for efficient removal of aqueous cesium

Development of innovative technology for solid waste disposal, particularly the synthesis of novel energy and environmental materials via upcycling of solid wastes, is essential for boosting sustainable development in urban areas. In this study, we developed a novel synthesis method for Prussian-blue-encapsulated pectin beads (PB@PD) using Fe and Ca sources in steel slag (SS) and demonstrated its feasibility for the removal of Cs+ via batch and fixed-bed column reactors. Hydrochloric acid (HCl) was used for Fe and Ca dissolution in the SS suspension, and the extracted Fe and Ca were then used for the synthesis of Prussian blue and pectin polymer beads, respectively. The surface characteristics of PB@PD were determined through advanced microscopy and surface analyses, which confirmed the successful formation of a PB crystal structure and well-distributed PB particles in the cross-linked pectin structure. Batch isotherm adsorption experiments conducted using PB@PD revealed that the maximum adsorption capacity of Cs+ was 54.34 mg/g. PB@PD could be recycled up to four times and was very effective for Cs+ adsorption in artificial seawater. Furthermore, we successfully applied PB@PD as a filling material in a fixed-bed column reactor and obtained an effective adsorption capacity (41.75–43.9 mg/g) without any clogging problem during the continuous Cs+ treatment.

Double-Walled Metal-Organic Framework with Regulable Pore Environments for Efficient Removal of Radioactive Cesium Cations.

An anion double-walled metal-organic framework [Co2Li4(BTC)3(DMF)(H2O)·(CH3)2N]n (1) based on heterobimetallic Li+ and Co2+ ions was successfully constructed. Utilizing selective destruction and formation of Co-O/Co-N bonds in the metal chains, [Co2Li4(BTC)3(py)(H2O)·(CH3)2N]n (2) and [Co2Li4(BTC)3(pi)(H2O)·(CH3)2N]n (3) with the same skeleton but distinct pore structures can be surprisingly obtained. Additionally, compounds 2 and 3 can be transformed into [Co2Li4(BTC)3(H2O)2·(CH3)2N]n (4) by soaking them in an ethanol solution. This kind of single-crystal-to-single-crystal transformation successfully regulates the pore structure of MOFs and enriches the diversity of the pore wall on the premise of retaining the original framework. Most impressively, compound 1 shows high adsorption capacity for Cs+ cations and is a good candidate to selectively accommodate Cs+ among the common alkali metal ions, which is future identified by single-crystal X-ray diffraction and inductively coupled plasma mass spectrometry (ICP-MS) test. Meanwhile, compound 1 can selectively adsorb methylene blue (MB) and crystal violet (CV) molecules over Rhodamine B (RMB).

Synthesis of magnetic nanoparticles-containing nanocomposite hydrogel and its potential application for simulated radioactive wastewater treatment

Nanocomposite hydrogels, bearing different functional groups, are potential materials for removing contaminants from water with high capacity and selectivity. A novel polyfunctional nanocomposite hydrogel (NCHG) was developed for the treatment of radioactive waste. It is based on magnetic composite nanoparticles (MCNPs) formed by encapsulating magnetite in polystyrene-co-polymethacrylic acid (PS-co-PMAA) miniemulsion. The MCNPs were then used as a physical crosslinker for the graft polymerization of sodium styrene sulfonate SSS and acrylic acid AA in the presence of polyacrylamide PAM to form an interconnected NCHG bearing different functional groups. The NCHG was characterized by FTIR, DLS, and TEM. The results indicated that a successful encapsulation of magnetite NPs took place and the MCNPs were ~100 nm in size. The presence of the MCNPs in the graft polymerization system greatly enhanced the conversion %. The optimum ultrasound homogenization of the polymerization reaction was found to be 11 min and the optimum gamma radiation dose for the initiation of polymerization reaction was 25 kGy. The NCHG was used for the removal of Cs+, Co2+, and Sr2+ ions from simulated radioactive waste. The initial concentration was studied from 50 to 600 mg/L, and the equilibrium adsorption capacities of Cs+, Co2+, and Sr2+ were found to increase from 8.49 to 53.37, 11.17–80.69, and 10.75–65.35 mg/g, respectively. The calculated thermodynamic parameters namely, Gibbs free energy (ΔG°), Enthalpy (ΔH°) and entropy (ΔS°) indicated an endothermic chemisorption process.

Adsorption of aniline by magnetic biochar with high magnetic separation efficiency

ABSTRACT The coprecipitation method was used to produce magnetic cotton straw biochar (MCS). Elemental analysis, FTIR, XRD, SEM, BET and magnetization curves were used to characterize MCS and CS. The results show that the MCS had excellent magnetic separation properties. When the pH value was higher than 5, the pH of the aniline solution had little effect on the adsorption capacity of MCS and CS. However, with increasing temperature, the adsorption capacity increased significantly. The maximum adsorption capacities of MCS and CS for aniline were 38.67 mg/g and 42.57 mg/g, respectively. The adsorption process of aniline was spontaneous, endothermic, and involved monolayer sorption and chemical adsorption. The adsorption capacity was due to the presence in magnetic biochar of phenolic hydroxyls and H-bond donors that adsorbed aniline. Therefore, the application of MCS presents good prospects for the removal of toxic and refractory aniline from water.

Synthesis of NiSiO@NiAlFe by Hydrothermal method and removal of Cs+ in water

In this work, novel NiSiO@NiAlFe layered double hydroxides (LDHs) hollow spheres were prepared by hydrothermal method. It could be observed that the grafting of LDHs towards NiSiO hollow spheres could avoid the LDHs’ aggregation, and thus enhance the material’s adsorption capacity. Furthermore, The effect of pH on adsorption Cs, kinetics and isotherm models were studied. Results indicated that NiSiO@NiAlFe LDHs hollow spheres had sufficient adsorption capability towards Cs+. The adsorption kinetics satisfied the pseudo-second-order adsorption model, Temkin model and Langmuir isotherm model. The adsorption process was efficient at the alkaline condition (pH=10). The adsorption kinetics indicated that the adsorption process could reach the equilibrium in only 20 minutes. The maximum adsorption capacity of Cs+ towards NiSiO@NiAlFe hollow spheres were estimated to be 61.5 mgg-1. Thus, NiSiO@NiAlFe hollow spheres presented a broad potential for treating cesium containing wastewater.

Effect of guest molecules on the adsorption properties of intercalated α-ZrP for Sr2+ and Cs+

The intercalated α-ZrP materials have been extensively concerned due to their excellent properties for removal of metal ions from complex system. However, the relationship between the metal ions and the intercalated materials need be investigated to better imply the intercalation mechanism. In this paper, three intercalated α-ZrP materials were prepared, and their ability for adsorption of Sr2+ and Cs+ was studied systemically. Intercalation of guest molecules into the layered structure of α-ZrP could significantly improve its adsorption properties for removal of Sr2+ and Cs+ ions. However, Sr2+ and Cs+ showed different adsorption behaviors on the intercalated α-ZrP materials. Both of the size of the intercalated molecules and hydration radius of the Sr2+ ions had a notable influence on Sr2+ adsorption capacity due to much more space was needed for Sr2+ ions moving during adsorption process, while the adsorption capacity for Cs+ is little affected by the size of the guest molecules, due to the smaller hydrated radius of Cs+ which allows it to move easily.

In situ assembly of PB/SiO2 composite PVDF membrane for selective removal of trace radiocesium from aqueous environment

A non-toxic and applicable surface-modified polyvinylidene fluoride (PVDF) membrane consisting of Prussian blue (PB) and aminating silica (A-SiO2) nanoparticles was fabricated for the selective removal of trace radionuclide cesium (Cs) from water. The modified membrane denoted as PB/A-SiO2/PVDF exhibited high selective removal of cesium with a high permeate flux of more than 800 L/h∙bar∙m2 in a wide pH range from 3 to 9. The adsorption experiments showed that the Langmuir isotherm model and the pseudo-second order model fitted well with the experimental results. The maximum adsorption capacity was 10.95 mg-Cs/g-membrane (i.e. 78.21 mg-Cs/g-PB sorbent on membrane) for the membrane at an initial Cs concentration of 50 mg/L. Based on the high Cs adsorption capacity of PB, the membrane could remove more than 97.5% Cs in the presence of the coexisting ions and organic matter for more than 10 h. The filtrated membrane could be effectively regenerated by NH4Cl, H2O2 and HNO3 solution with negligible decrease in removal efficiency after repeated use. With the high membrane flux and selective removal efficiency, the fabricated membrane can be potentially applied in Cs contaminated water treatment.

Highly selective enrichment of radioactive cesium from solution by using zinc hexacyanoferrate(III)-functionalized magnetic bentonite

Realizing highly effective and selective enrichment of radioactive Cs(I) in complex environmental systems and exploring the microscale adsorption mechanism of Cs(I) on adsorbing material is the key point for developing highly efficient materials for Cs(I) adsorption. In addition, the low cytotoxicity of materials is essential for practical applications and environmental protection. In this study, the controlled assembly of bentonite carrier with a highly selective substance of Cs(I) is prepared by in-situ synthesis method in order to construct a low-toxic functional clay material with high adsorption capacity and selectivity of Cs(I) in complex environmental systems. The efficiency of the zinc hexacyanoferrate(III)-grafted magnetic bentonite (denoted as ZHF/MB) composite was evaluated in adsorption isotherm studies, kinetics analyses, and selectivity tests by using the batch technique. The toxicity of the ZHF/MB composite was evaluated through in vitro cytotoxicity assays using human hepatic cells (HepG2 cells). The results revealed that the ZHF/MB composite had not only a higher adsorption capacity (1.638 mmol/g, 60 °C) for Cs+ ions than a number of other natural and manmade materials but also no cytotoxicity in human cells. In addition, the ZHF/MB composite showed excellent selectivity for Cs+ with a removal efficiency of over 90% from solution (m/V = 0.4 g/L, [Mn+]initial = 10 mg/L, Mn+= Cs+, Ni2+,Sr2+, Co2+). The promising safe toxicology profile, remarkable Cs+ adsorption efficiency, and excellent selectivity of the ZHF/MB composite demonstrate its great potential for using as a decorporation agent for radioactive cesium remediation. The implementation of this research will provide new adsorption materials and method for radioactive Cs(I) waste management.

Prediction and optimization of adsorption properties for Cs+on NiSiO@NiAlFe LDHs hollow spheres from aqueous solution: Kinetics, isotherms, and BBD model

In this work, novel NiSiO@NiAlFe layered double hydroxides (LDHs) hollow spheres were prepared by hydrothermal method. It was worth noting that LDHs’ grafting towards NiSiO hollow spheres could avoid the LDHs’ aggregation, and thus enhanced the material’s adsorption capacity. Furthermore, adsorption kinetics, adsorption isotherms, and Box-Behnken Design (BBD) model were conducted. Results indicated that NiSiO@NiAlFe LDHs hollow spheres had sufficient adsorption capability towards Cs+. The adsorption kinetics satisfied the pseudo-second-order adsorption model, Temkin model and Langmuir isotherm model. The adsorption process was efficient at the alkaline condition (pH = 10). The adsorption kinetics indicated that the adsorption process could reach the equilibrium in only 20 min. The maximum adsorption capacity of Cs+ towards NiSiO@NiAlFe LDHs hollow spheres was estimated to be 61.5 mg g−1. Moreover, the adsorption thermodynamics indicated that the adsorption process was exothermal, feasible and spontaneous. Thus, NiSiO@NiAlFe LDHs hollow spheres presented a broad potential for treating cesium containing wastewater.

Combined use of tannic acid-type organic composite adsorbents and ozone for simultaneous removal of various kinds of radionuclides in river water

Tannic acid-type organic composite adsorbents (PA316TAS, AR-01TAS, PYRTAS, WA10TAS, WA20TAS, and WA30TAS), combined with hydrolyzed and sulfonated tannic acid (TAS) and porous-type strongly basic anion-exchange resin (PA316), benzimidazole-type anion-exchange resin embedded in high-porous silica beads (AR-01), pyridine-type anion-exchange resin (PYR), acrylic-type weakly basic anion-exchange resin (WA10), or styrene-type weakly basic anion-exchange resins (WA20 and WA30) for simultaneous removal of various kinds of radionuclides in river water were successfully synthesized. The adsorption behavior of twelve kinds of simulated radionuclides (Mn, Co, Sr, Y, Ru, Rh, Sb, Te, Cs, Ba, Eu, and I (I− and IO3−)) on these composite adsorbents has been studied in real river water at room temperature. PA316TAS adsorbents showed much higher distribution coefficients (Kd) for all metal ions. TAS structure has more selective adsorption ability for Mn, Co, Sr, Y, Cs, Ba, Eu, and IO3−. On the other hand, Y, Ru, Rh, Sb, Te, Eu, I (I− and IO3−) were adsorbed on both PA316 and TAS structures. To evaluate the validity of these mechanistic expectations, the respective chemical adsorption behaviors of Mn, Co, Sr, etc. and PA316TAS adsorbent were examined in river water ranging in temperature from 278 to 333 K. As was expected, one adsorption mechanism for Mn, Co, Sr, Cs, and Ba systems and two types of adsorption mechanisms for Y, Ru, Rh, Sb, Te, Eu, I (I− and IO3−) systems were observed. On the other hand, the precipitation of Mn, Co, Y, Ru, Rh, Te, and Eu was formed by ozonation for river water, that is, ozone can transform Mn, Co, Y, Ru, Rh, Te, and Eu ions into the insoluble precipitates. Hence, one straight line for Sr, Cs, Ba systems and two types of straight lines for Sb, I (I− and IO3−) systems were obtained in river water treated with ozone. The chromatography experiments of Cs, Sr, I (I− and IO3−) were carried out to calculate their maximum adsorption capacities. The obtained maximum adsorption capacities of Cs, Sr, and I− mixed with IO3− were 1.7 × 10−4 (Cs), 1.8 × 10−3 (Cs/O3), 7.8 × 10−5 (Sr), 5.6 × 10−4 (Sr/O3), 5.4 × 10−2 (I− and IO3−), 3.1 × 10−2 (I− and IO3−/O3) mol/g - PA316TAS. It was discovered that the maximum adsorption capacities of I− and IO3− for the composite adsorbent is unprecedented high and the capacity become much greater than an order of magnitude, compared with those of previous reports. This phenomenon suggests the formation of electron-donor-acceptor (EDA) complexes or pseudo EDA complex. Based on these results, it was concluded that the combined use of tannic acid-type organic composite adsorbents and ozone made it possible to remove simultaneously and effectively various kinds of radionuclides in river water in the wide pH and temperature ranges.

Synthesis of Calcium Silicate Hydrate Compounds From Wet Flue Gas Desulfurization (FGD) Waste

In this study Calcium silicate hydrate based products (CSHP) were synthesized from wet flue gas desulfurization waste (FGD) by alkali fusion followed by hydrothermal treatment. The effect of various factors on the formation of products, such as mineralizing agent, fusion temperature and time, crystallization time and addition of Ca and Si were studied as well as the conditions optimized. The FGD and synthesized materials were characterized by using X-Ray (XRD), Scanning Electron Microscope (SEM), X-ray fluorescence (XFR), among other methods. A fusion temperature of 600 °C with NaOH, fusion duration of 1 h, and a subsequent hydrothermal temperature of 100 °C for a reaction of 24 h were found to be the optimal conditions. In these synthesis conditions, CSHP containing tobermorite and Al-tobermorite was the major phases. The synthesized CSHP revealed high selective uptake for Cs+ in water. The maximum adsorption capacity of Cs+ onto the synthesized material, as calculated from the Langmuir model, was 1949 µmol g-1. The performance on the Cs+ removal in the presence of high Na+ contents was also evaluated. The adsorbent material showed a high Cs+ adsorption capacity in deionized water and a decrease of 56% and 62% in saturated media with the Na+ ions and seawater, respectively. Therefore, CSHP as a higher value-added product can be obtained from a by-product of a coal-fired power plant, which has wide range applications, including for Cs+ removal from wastewater.

Adsorption Performance for Reactive Blue 221 Dye of β-Chitosan/Polyamine Functionalized Graphene Oxide Hybrid Adsorbent with High Acid-Alkali Resistance Stability in Different Acid-Alkaline Environments.

A hybrid material obtained by blending β-chitosan (CS) with triethylenetetramine-functionalized graphene oxide (TFGO) (CSGO), was used as an adsorbent for a reactive dye (C.I. Reactive Blue 221 Dye, RB221), and the adsorption and removal performances of unmodified CS and mix-modified CSGO were investigated and compared systematically at different pH values (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, and 12). The adsorption capacities of CS and CSGO were 45.5 and 56.1 mg/g, respectively, at a pH of 2 and 5.4 and 37.2 mg/g, respectively, at a pH of 12. This indicates that TFGO was successfully introduced into CSGO, enabling π–π interactions and electrostatic attraction with the dye molecules. Additionally, benzene ring-shaped GO exhibited a high surface chemical stability, which was conducive to maintaining the stability of the acid and alkali resistance of the CSGO adsorbent. The RB221 adsorption performance of CS and CSGO at acidic condition (pH 3) and alkaline condition (pH 12) and different temperatures was investigated by calculating the adsorption kinetics and isotherms of adsorbents. Overall, the adsorption efficiency of CSGO was superior to that of CS; thus, CSGO is promising for the treatment of dye effluents in a wide pH range.

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.