Molten salts for efficient removal of radioactive contaminants from stainless steel surface: Mechanisms and applications.

Here, we have demonstrated an innovative decontamination strategy using molten salts as a solvent to clean stubborn uranium contaminants on stainless steel surfaces. The aim of this work was to investigate the evolutionary path of contaminants in molten salts to reveal the decontamination mechanism, thus providing a basis for the practical application of the method. Thermodynamic analysis revealed that alkali metal hydroxides, carbonates, chlorides and nitrates can react with uranium oxides (UO and UO) to form various uranates.

Efficient capture of uranium by a hydroxyapatite-modified polyethyleneimine@carbon nanotube composite from radioactive nuclear waste.

The toxicity and radioactivity of uranium (U)-containing wastewater pose a serious threat to the environment of humans, animals, and plants. It is necessary to remove U from contaminated wastewater. With high adsorption capacity and fast adsorption rate, a composite CNT-P/HAP, which comprises carbon nanotubes (CNT) modified with polyethyleneimine (PEI), was functionalized further by hydroxyapatite (HAP) using the hydrothermal method.

The effect of air on oxidation decomposition of uranium-containing cationic exchange resins in LiCO-NaCO-KCO molten-salt system.

With the development of nuclear energy, spent cationic exchange resins after purification of radioactive wastewater must be treated. Molten-salt oxidation (MSO) can minimize the disposal content of resins and capture SO. In this work, the decomposition of uranium-containing resins in carbonate molten salt in N and air atmospheres was investigated.

Electrocatalytic and green system coupling strategy for simultaneous recovery and purification of uranium from uranium-containing wastewater.

The recycling of uranium in wastewater is not only beneficial to the protection of ecological safety but also has great significance for the sustainable development of nuclear energy. However, there is no satisfactory method to recover and reuse uranium efficiently up to now. Here, we have developed an efficient and economical strategy that can achieve uranium recovery and direct reuse in wastewater.

Effect of copper ions on transformation of organic sulfur in cationic exchange resins in LiCO-NaCO-KCO molten-salt system.

Cationic exchange resins (CERs) were applied for purification and clarifying process of radioactive wastewater in nuclear industry, which was a kind of sulfur-containing organic material. Molten-salt oxidation (MSO) method can be applied for the treatment of spent CERs and the absorption of acid gas (such as SO). The experiments about the molten salt destruction of the original resin and Cu ions doped resin were conducted.

Decontamination of uranium-containing radioactive waste from stainless steel surfaces using NaOH-based molten salts.

Herein, we report a new strategy for the rapid removal of uranium-containing contaminants from metal surfaces, and it relies on decontaminants made of NaOH-based molten salts. The addition of NaCO and NaCl to NaOH exhibited superior decontamination performance, with a decontamination rate of 93.8% within 12 min, outdoing the performance of the single NaOH molten salt.

Effects of oxygen content on gaseous and solid products during molten salt oxidation of cation exchange resins.

Molten salt oxidation (MSO) is an advanced method for waste resins treatment; nevertheless, the research about gas product variations of resins under different stoichiometric air feed coefficient (α) is rare. The optimal working condition of hazardous waste disposal is obtained through thermodynamic equilibrium calculation, and the method to improve the treatment efficiency is found to guide the optimization of the actual experiment. In this paper, Fact Sage was used to calculate the oxidation products of cation exchange resins (CERs) at different temperatures and α, focusing on the similarities and differences through the contents of CO, CH, CO, and SO during the oxidation of CERs, the MSO of CERs, and the theoretical calculation.

Catalytic effect of cesium on the oxidation behavior of cation exchange resins in LiCO-NaCO-KCO melt.

After the treatment of liquid radioactive waste, there is a certain amount of Cs in the waste resin, and these Cs-doped resins are prone to volatilize during the thermal treatment process and cause radionuclide leakage. The molten salt oxidation (MSO) can effectively prevent the volatilization of toxic metal, especially the volatilization of Cs. Under nitrogen and air conditions, it is found that the oxidation behavior between Cs-doped and clean cation exchange resins (CERs) is quite different.

Valence regulation investigation of key factors on the electrochemical immobilization uranyl from wastewater.

Electrochemical techniques are considered promising applications to immobilize uranium in alkaline wastewater in order to prevent its migration into groundwater and soil. In this work, the results of electrochemical and Atomic Force Microscope (AFM) demonstrate a successful immobilization of uranyl in the carbonate system by U(VI)-U(V), U(V)-U(IV) reduction, and U(V) disproportionation reactions. The results indicated that the electrochemical fixation rate in alkaline system could reach more than 99%.

Molten salt/liquid metal extraction: Electrochemical behaviors and thermodynamics properties of La, Pr, U and separation factors of La/U and Pr/U couples in liquid gallium cathode.

The electrochemical behavior of lanthanides (La, Pr) and actinide (U) on inert W and liquid Ga electrodes in LiCl-KCl molten salt as well as their related thermodynamic properties were experimentally determined for further Lns/Ans separation. The results indicate that the reductions of La and Pr in LiCl-KCl melts are both one-step process with three electrons exchanged, and the reactions are quasi-reversible processes at low scan rate. Temperature dependencies of apparent standard redox potentials of La(Ga), Pr(Ga) and U(Ga) alloys were determined by open-circuit chronopotentiometry versus Cl/Cl reference electrode.

Construction of reduced graphene oxide coupled with CoSe-MoSe heterostructure for enhanced electrocatalytic hydrogen production.

It is important to develop novel energy to solve energy shortage and environmental problems. Hydrogen evolution reaction (HER) is envisaged as a viable technology that can be used to develop sustainable clean energy. Herein, we report a catalyst with CoSe-MoSe heterostructure grown on reduced graphene oxide with an optimum Co/Mo proportion of 1:1 (CoSe-MoSe(1-1)/rGO).

Preparation and Corrosion Performance of PPy/Silane Film on AZ31 Magnesium Alloy via One-Step Cyclic Voltammetry.

PPy/silane composite film on a magnesium alloy surface was prepared by one-step cycle voltammetry. The mixed solution of methanol and water was used as the hydrolysis solvent of a γ-(2,3-glycidoxypropyl) trimethoxysilane coupling agent (KH-560). The surface morphology of the PPy/silane film, the electro-polymerization progress of KH-560 and PPy, the influence of the silane coupling agent and the corrosion behavior of the coated AZ31 Mg alloy were all investigated.

Iron molybdenum selenide supported on reduced graphene oxide as an efficient hydrogen electrocatalyst in acidic and alkaline media.

It is of great significance to develop inexpensive and high-efficiency electrocatalysts for the hydrogen evolution reaction (HER). In this work, we synthesized iron molybdenum selenide (FeSe-MoSe) loaded on reduced graphene oxide (FeSe-MoSe/rGO) by a one-step hydrothermal method. We further optimized the Fe/Mo ratio and determined the best ratio to be 1-1.

Water-locking molecule-assisted fabrication of nature-inspired Mg(OH) for highly efficient and economical uranium capture.

With the depletion of uranium terrestrial deposits, researchers have focused on the development of adsorbents to extract radioactive uranium from seawater/wastewater. However, the artificial manipulation of adsorbents for the cost-effective extraction of radioactive uranium from large numbers of water samples is still significantly challenging. Herein, a facile yet versatile stepwise strategy has been reported for the fabrication of adsorbents.