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•Oriented functionalization of Zn-Al-Ti LMO is performed under different conditions for U(VI) removal.•Adsorption of U(VI) nearly approaches equilibrium within 200 min.•The maximum ...adsorption capacity of U(VI) by Zn-Al-Ti LMO@PA5 is up to 1486 mg/g.•Adsorption mechanisms are characterized by the strong chelation of PA and U(VI).
The efficient treatment of uranium (U) is an important and challenging issue regarding radioactive wastes management. Adsorbent with high efficacy, low-cost is urgently needed for alleviating the contamination of U-containing wastewaters. To solve these issues, we report a series of phytic acid (PA) modified Zn-Al-Ti layered mixed metal oxides (Zn-Al-Ti LMO@PAs) in this work, which shows the adsorption capacity as high as ∼1486 mg/g and could be easily obtained through a facile post-modification method. The adsorption performance of Zn-Al-Ti LMO@PAs for U(VI) are carefully estimated through batch experiments. With the aid of batch experiments and various characterization techniques, PA in Zn-Al-Ti LMO@PAs is found to make the most contribution for the chelation of U(VI), which favors for the adsorption selectivity and capability. The Zn-Al-Ti LMO@PAs are potential cost-effective adsorbents to remove the U(VI) in wastewaters.
Biosorption of heavy metal elements including radionuclides by microorganisms is a promising and effective method for the remediation of the contaminated places. The responses of live Saccharomyces ...cerevisiae in the toxic uranium solutions during the biosorption process and the mechanism of uranium biomineralization by cells were investigated in the present study. A novel experimental phenomenon that uranium concentrations have negative correlation with pH values and positive correlation with phosphate concentrations in the supernatant was observed, indicating that hydrogen ions, phosphate ions and uranyl ions were involved in the chernikovite precipitation actively. During the biosorption process, live cells desorb deposited uranium within the equilibrium state of biosorption system was reached and the phosphorus concentration increased gradually in the supernatant. These metabolic detoxification behaviours could significantly alleviate uranium toxicity and protect the survival of the cells better in the environment. The results of microscopic and spectroscopic analysis demonstrated that the precipitate on the cell surface was a type of uranium-phosphate compound in the form of a scale-like substance, and S. cerevisiae could transform the uranium precipitate into crystalline state-tetragonal chernikovite H2(UO2)2(PO4)2·8H2O.
The mechanisms of uranium biosorption and biomineralization by live S. cerevisiae. Display omitted
•Hydrogen ions, phosphate and uranyl ions could form a chernikovite precipitate.•Uranium desorption and phosphorus release are cell responses in uranium solution.•Tetragonal crystals of chernikovite were formed.
The accident at the Fukushima Daiichi nuclear power plant four years ago has drawn attention to the environmental impact that the release of fission products from nuclear fuels can have in the event ...of a severely damaged reactor core. Three such accidents have occurred in the history of civil nuclear power.
Progress in chemistry over the past four decades has generated a variety of porous materials for removing iodine—a radioactive emission accompanying nuclear fission. However, most studies are still ...based on the notion that entangled pores together with specific binding sites are essential for iodine capture. Here, an unraveled physical picture of iodine capture that overturns the preconception by exploring 1D channeled porous materials is disclosed. 2D covalent organic frameworks are constructed in a way so that they are free of interpenetration and binding sites but consist of 1D open channels. As verified with different channels shaping from hexagonal to tetragonal and trigonal and ranging from micropores to mesopores, all the 1D channels enable a full access to iodine, generalizing a new paradigm that the pore volume determines the uptake capacity. These results are of fundamental importance to understanding iodine uptake and designing materials to treat coagulative toxic vapors.
Two‐dimensional covalent organic frameworks enable the full occupation of their one‐dimensional channel space for capturing iodine, leading to an exceptional capacity.
The rising use of radioactive elements is increasing radioactive pollution and calling for advanced materials to protect individuals. For instance, polymers are promising due to their mechanical, ...electrical, thermal, and multifunctional properties. Moreover, composites made of polymers and high atomic number fillers should allow to obtain material with low-weight, good flexibility, and good processability. Here we review the synthesis of polymer materials for radiation protection, with focus on the role of the nanofillers. We discuss the effectivness of polymeric materials for the absorption of fast neutrons. We also present the recycling of polymers into composites.
The environmental impacts of the nuclear accidents of Chernobyl and Fukushima are compared. In almost every respect, the consequences of the Chernobyl accident clearly exceeded those of the Fukushima ...accident. In both accidents, most of the radioactivity released was due to volatile radionuclides (noble gases, iodine, cesium, tellurium). However, the amount of refractory elements (including actinides) emitted in the course of the Chernobyl accident was approximately four orders of magnitude higher than during the Fukushima accident. For Chernobyl, a total release of 5300PBq (excluding noble gases) has been established as the most cited source term. For Fukushima, we estimated a total source term of 520 (340–800) PBq. In the course of the Fukushima accident, the majority of the radionuclides (more than 80%) was transported offshore and deposited in the Pacific Ocean. Monitoring campaigns after both accidents reveal that the environmental impact of the Chernobyl accident was much greater than of the Fukushima accident. Both the highly contaminated areas and the evacuated areas are smaller around Fukushima and the projected health effects in Japan are significantly lower than after the Chernobyl accident. This is mainly due to the fact that food safety campaigns and evacuations worked quickly and efficiently after the Fukushima accident. In contrast to Chernobyl, no fatalities due to acute radiation effects occurred in Fukushima.
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•The environmental effects of Chernobyl and Fukushima are compared.•Releases of radionuclides from Chernobyl exceeded Fukushima by an order of magnitude.•Chernobyl caused more severe radiation-related health effects.•Overall, Chernobyl was a much more severe nuclear accident than Fukushima.•Psychological effects are neglected but important consequences of nuclear accidents.
The extensive application of radioactive element uranium (U) and its compounds in the nuclear industry has significantly increased the risk of exposure to the environment. Therefore, research on the ...safety risks and toxicity mechanisms of U exposure has received increasing attention. This paper reviews the toxic effects of U on different species under different conditions, and summarizes the potential toxicity mechanisms. Under the exposure of U, reactive oxygen species (ROS) produced in cells will damage membrane structure in cells, and inhibit respiratory chain reaction by reducing the production of NADH and ATP. It also induce the expression of apoptosis factors such as Bcl-2, Bid, Bax, and caspase family to cause apoptosis cascade reaction, leading to DNA degradation and cell death. We innovatively list some methods to reduce the toxicity of U because some microorganisms can precipitate uranyl ions through biomineralization or reduction processes. Our work provides a solid foundation for further risk assessment of U.
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•The effects of different factors on the biotoxicity of U were classified and compared.•The methods for reducing U toxicity by microorganisms was summarized.•The toxic mechanism of U was comprehensively summarized.
The European Atlas of Natural Radiation is a collection of maps displaying the levels of natural radioactivity caused by different sources. It has been developed and is being maintained by the Joint ...Research Centre (JRC) of the European Commission, in line with its mission, based on the Euratom Treaty: to collect, validate and report information on radioactivity levels in the environment of the EU Member States.
This work describes the first version of the European Atlas of Natural Radiation, available in digital format through a web portal, as well as the methodology and results for the maps already developed. So far the digital Atlas contains: an annual cosmic-ray dose map; a map of indoor radon concentration; maps of uranium, thorium and potassium concentration in soil and in bedrock; a terrestrial gamma dose rate map; and a map of soil permeability.
Through these maps, the public will be able to: familiarize itself with natural environmental radioactivity; be informed about the levels of natural radioactivity caused by different sources; have a more balanced view of the annual dose received by the European population, to which natural radioactivity is the largest contributor; and make direct comparisons between doses from natural sources of ionizing radiation and those from man-made (artificial) ones, hence, to better assess the latter.
Work will continue on the European Geogenic Radon Map and on estimating the annual dose that the public may receive from natural radioactivity, by combining all the information from the different maps. More maps could be added to the Atlas, such us radon in outdoor air and in water and concentration of radionuclides in water, even if these sources usually contribute less to the total exposure.
•Radioactive Environmental Monitoring web portal to provide radiological information.•European Atlas of Natural Radiation to inform about natural radioactivity in Europe.•11 maps displaying the levels of radioactivity caused by different natural sources.•Data collection, statistical analysis, and mapping.•Digital version of the European Atlas of Natural Radiation: map viewer and description.
The beginning of the atomic age marked the outset of nuclear weapons testing, which is responsible for the radioactive contamination of a large number of sites worldwide. The paper aims to analyze ...nuclear weapons tests conducted in the second half of the twentieth century, highlighting the impact of radioactive pollution on the atmospheric, aquatic, and underground environments. Special attention was given to the concentration of main radioactive isotopes which were released, such as ¹⁴C, ¹³⁷Cs, and ⁹⁰Sr, generally stored in the atmosphere and marine environment. In addition, an attempt was made to trace the spatial delimitation of the most heavily contaminated sites worldwide, and to note the human exposure which has caused a significantly increased incidence of thyroidal cancer locally and regionally. The United States is one of the important examples of assessing the correlation between the increase in the thyroid cancer incidence rate and the continental-scale radioactive contamination with ¹³¹I, a radioactive isotope which was released in large amounts during the nuclear tests carried out in the main test site, Nevada.
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