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In this study, polyacrylonitrile was modified to polyamidoxime to enhance foam stabilization and decontamination rate. Polyamidoxime was combined with graphene oxide, 1 wt% of saponins, and 1 wt% of alkyl glycosides to formulate the PAO/GO foam decontaminant. The outcomes demonstrated resulted in the half-life of the foam extending from 32 to 308 min. The PAO/GO foam decontaminant displayed α-ray decontamination rates of 93.30%, 98.34%, and 99.81% on stainless steel, tile, and glass surfaces. Hence, the dual functional PAO/GO in stabilizing foam while enhancing decontamination rates underscores its potential for radioactive decontamination. [ABSTRACT FROM AUTHOR]

Radioactive aerosols produced by nuclear accidents and decommissioning of nuclear power plants would cause tremendous radioactive damage to the environment and human body. The development of a radioactive aerosol suppressant is of great significance in the treatment of radioactive aerosols. In this study, a three-dimensional biomass-based polymer pectin-g-acrylic acid-acrylamide (pectin-g-poly (AA-co-AM)) SAP with high water absorbency and high agglomeration was prepared by solution polymerization. The results showed that the water absorbency of pectin grafted with acrylic acid and acrylamide reached 1064 g/g. Furthermore, under the synergistic effect of water absorption and agglomeration of the material, the sedimentation efficiency of simulated radioactive aerosol by 30 min after using suppressant is 91.21%. [ABSTRACT FROM AUTHOR]

Electret fiber filtration materials prepared by electrostatic spinning and corona polarization have drawn significant interest in treating radioactive aerosols. In this study, a three-dimensional biomass-based electret nanofiber aerogel material with high dust capacity, high filtration efficiency and low-pressure drop was created by pore structure regulation. The results showed that aerogels with good charge capture and storage ability were obtained by regulating the concentration of tert-butanol and ethylcellulose fiber suspension, and the pre-freezing temperature. The initial surface potential and stable surface potential increased from 0.85 and 0.05 kV to 1.37 and 0.15 kV respectively. Furthermore, the purification time was reduced from 44 to 15 min. [ABSTRACT FROM AUTHOR]

Conventional water-based detergents cannot remove radioactive contamination on the surface below 0 °C. In order to solve this problem, a biodegradable antifreeze foam, containing the antifreeze, the chelating agent and the surfactant in the low pH complex system, has been developed with the small molecule lauryl alcohol (LA) as the foam stabilizer. The developed foam being with short decontamination time which is easy to use and collect, can significantly reduce the amount of radioactive waste. The foam has good stability and decontamination efficiency as low as − 10 °C. The stabilization mechanism of LA on foam was studied. At the range of from 0 to − 10 °C, the decontamination rates of simulated radioactive cesium (Cs) and strontium (Sr) pollution are all above 90% on surfaces with different roughness such as glass, stainless steel, ceramic tile, marble and paint. [ABSTRACT FROM AUTHOR]

In this study, hydrothermal carbon doped with phosphorus using phytic acid (PA) and Sodium tripolyphosphate as functional monomers was successfully synthesized by the hydrothermal route combined with microwave-assisted hydrothermal carbon as matrix material. The uranium(VI) adsorption capacity by phytic acid functionalized microwave-assisted hydrothermal carbon (MHC-PA) was up to 382.2 mg/g at pH of 6.0 and the temperature of 298.15 K. The adsorption mechanism of uranium(VI) onto the MHC-PA was mainly the chelation of P=O, P–OH functional group and uranium(VI), which improves the selective adsorption performance of MHC-PA for uranium(VI). [ABSTRACT FROM AUTHOR]

In this study, the effect of synthesis temperature and time on the morphology and structure of the carbon microspheres was investigated. The comparation between traditional hydrothermal and microwave-assisted hydrothermal method for preparing carbon materials was carried out. Finally, the adsorption performance of the material for uranium (VI) was tested. The results showed that microwave method has better heating rate than conventional hydrothermal method, the carbon material prepared by microwave-assisted hydrothermal method at low temperature and short time has excellent adsorption performance, and the maximum adsorption amount can reach 170.07 mg/g for uranium (VI). [ABSTRACT FROM AUTHOR]

Stereoscopic porous microspheres based gellan gum (GG-Ca) were successfully prepared by sol-gel method using ethyl acetate as porogen and glutaraldehyde as crosslinker. The obtained GG-Ca microspheres were mainly of mesoporous with the average pore diameter was about 4 nm. It displayed a higher ability for uranium removal. In addition, the uranium adsorption process was endothermic and spontaneous following a pseudo-second-order and the adsorption isotherm was the best fit with the Freundlich model with maximum uranium capacity of 202.26 mg g−1. The UO2+ adsorption mechanism is ion-exchange with Ca2+ based on SEM, EDX and XPS data analysis. [ABSTRACT FROM AUTHOR]

Core–shell nanoscale zero-valent iron@alginate/carboxymethyl cellulose sodium composite loaded with calcium (nZVI@SA/CMC-Ca) beads were synthesized in this study using coaxial electronic injection method. The adsorbent structure was characterized via FT-IR, SEM, EDX and XPS. The adsorption behavior of U(VI) and Cu(II) on core–shell nZVI@SA/CMC-Ca beads was studied under various experimental parameters like pH, contact time and temperature. The isotherm and the kinetic data, pertaining to the adsorption of U(VI) and Cu(II) by core–shell nZVI@SA/CMC-Ca beads obeyed both the Langmuir and Freundlich isotherms model and the pseudo-second-order kinetics model, respectively. The thermodynamic parameters revealed the spontaneous and endothermic nature of the adsorption. The experiment of regeneration and reusability suggested core–shell nZVI@SA/CMC-Ca bead was a regenerated material. [ABSTRACT FROM AUTHOR]

In this study, the core-shell nanoscale zero-valent iron (nZVI)@Alg-Ca beads were synthesized by coaxial electronic injection method for removal of U (VI) from aqueous solution, and characterized by SEM, EDX and XPS. The results showed that the pseudo-second-order models and the Langmuir isotherm model fitted well with the data obtained. The removal mechanism may include both physical adsorption of U (VI) on the surface or inside of core-shell nZVI@Alg-Ca beads and subsequent reduction of U (VI) to U (IV). Therefore, the core-shell nZVI@Alg-Ca beads would have an application prospect in effective removal of U (VI) contamination from aqueous solution. [ABSTRACT FROM AUTHOR]

The chemically oxidized porous carbon (m-a-NC) materials were prepared by oxidation and activation of N-doped carbon (NC) materials which were produced from the glucose-urea resin primary carbon. Simultaneously, the batch experiments were carried out to investigate the adsorption of U(VI) onto the m-a-NC materials. The m-a-NC materials exhibit the maximum adsorption capacity of 397 mg/g towards U(VI) at 298.15 K and pH = 4.5. The adsorption kinetics was well fitted by the pseudo-second-order kinetic model, and the adsorption isotherm was better described by the Langmuir model. The possible adsorption mechanism of the m-a-NC for U(VI) was ion-exchange and coordination. [ABSTRACT FROM AUTHOR]

The microsphere of carboxymethyl konjac glucomannan immobilizing La and Al (CMKGM-La-Al) has been explored for sorption of U(VI). The maximum U(VI) sorption capacity of the microsphere is found to be 45.4 mg g at pH 5. Experimental data are fitted well with the linear Langmuir and linear pseudo-first-order kinetic model. The sorption process is endothermic, spontaneous and favorable. The possible mechanism of CMKGM modification and sorption of U(VI) on CMKGM-La-Al involves ion exchange and coordination reaction. The comparison between CMKGM-La-Al and other sorbents suggests that CMKGM-La-Al can be considered as an effective sorbent for U(VI) sorption. [ABSTRACT FROM AUTHOR]

Alginate-Ca/attapulgite clay core/shell particles were synthesized via electro-coextrusion. Affecting parameters on the removal of uranium, such as pH, initial uranium concentration, temperature and co-existing cations were investigated. The uranium adsorption process was endothermic, feasible and spontaneous. The maximum adsorption capacity of the adsorbent for uranium was 199.345 mg/g at pH 3 and at 328.15 K. The results showed that the pseudo-second-order model and the Langmuir isotherm model fitted well with the data obtained. Based on the adsorption-desorption study, the adsorbent shows excellent reusability. The mechanism of uranium adsorption on the adsorbent was a combination of ion-exchange and an electrostatic interaction. [ABSTRACT FROM AUTHOR]

A novel microsphere adsorbent based upon carboxymethyl cellulose sodium/prussian blue composite loaded with Lanthanum(III) (CMC/PB-La) was successfully synthesized via electrostatic ejection device for removal of cesium from contaminated water, and characterized by FT-IR, SEM, EDX and XPS. Influencing factors to adsorption cesium were investigated, including solution pH, adsorbent dosage, contact time, initial concentration, temperature and competing ions. Linear Freundlich isotherm was fitted satisfactorily to the adsorption data, and the adsorption kinetic data was fitted well with pseudo-second-order model. Moreover, the results of γ-irradiation experiments indicate that CMC/PB-La has good radiation stability. [ABSTRACT FROM AUTHOR]

The carbon microsphere which possesses a large number of carboxyl groups on its surface was synthesized by hydrothermal treatment from aqueous glucose solutions at 130 °C and further calcination. The results showed that the maximum adsorption capacity (163 mg/g) of the carbon microspheres towards U(VI) was obtained, and the adsorption kinetic was well fitted by the pseudo-second-order kinetic model. Meanwhile, the adsorption isotherm was better described by the Langmuir model. The thermodynamic parameters indicated the adsorption process was an endothermic and spontaneous process. The possible adsorption mechanism of the carbon microspheres for U(VI) involves ion-exchange and coordination reaction. [ABSTRACT FROM AUTHOR]

The carboxymethyl cellulose microsphere loaded with Al(III) (CMC-Al) has been explored for removal of uranium(VI) from U-containing water. Various factors, including pH, adsorbent dosage and uranium(VI) concentration, were tested. Langmuir and Freundlich isotherms were applied to the adsorption data. The thermodynamic parameters such as Δ H°, Δ S° and Δ G° were also evaluated. The mechanism of modification and adsorption on CMC-Al were analyzed by SEM, EDX and XPS. Results show Al (III) was loaded on CMC through ion exchange of sodium ion of CMC. The coordination reaction happened during the adsorption process between CMC-Al and uranium(VI). [ABSTRACT FROM AUTHOR]

Uranium (VI)-containing water has been recognized as a potential longer-term radiological health hazard. In this work, the sorptive potential of sunflower straw for U (VI) from aqueous solution was investigated in detail, including the effect of initial solution pH, adsorbent dosage, temperature, contact time and initial U (VI) concentration. A dose of 2.0 g L −1 of sunflower straw in an initial U (VI) concentration of 20 mg L −1 with an initial pH of 5.0 and a contact time of 10 h resulted in the maximum U (VI) uptake (about 6.96 mg g −1) at 298 K. The isotherm adsorption data was modeled best by the nonlinear Langmuir–Freundlich equation. The equilibrium sorption capacity of sunflower straw was observed to be approximately seven times higher than that of coconut-shell activated carbon as 251.52 and 32.37 mg g −1 under optimal conditions, respectively. The positive enthalpy and negative free energy suggested the endothermic and spontaneous nature of sorption, respectively. The kinetic data conformed successfully to the pseudo-second-order equation. Furthermore, energy dispersive X-ray, fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy demonstrated that U (VI) adsorption onto sunflower straw was predominantly controlled by ion exchange as well as complexation mechanism. The study revealed that sunflower straw could be exploited for uranium remediation of aqueous streams as a promising adsorbent. [ABSTRACT FROM AUTHOR]

The extraction of uranium from strong acidic radioactive wastewater is vital and challenging to sustainable development of nuclear energy. In order to improve the selective uranium adsorption, a phytic acid decorated multiple hydorgel network (MA-U-PA/GG-CS-Ca) was constructed by incorporating phytic acid modified covalent organic polymers to gellan gum and chitosan hydrogel by supramolecular self-assembly. The results indicated that the selectivity ratio (SU) of MA-U-PA/GG-CS-Ca for uranium adsorption increased from 28 to 72%. The adjacent –P = O groups within the phytic acid molecule reduces the free energy of the coordination reaction with uranium, which is favorable to the uranium adsorption under acidic condition. [ABSTRACT FROM AUTHOR]