摘要：
A series of compositionally complex A2Zr2O7 nanocrystalline ceramics were successfully prepared using sol-gel and co-precipitation methods. The resultant ceramics possess a cubic defect fluorite structure, with the sol-gel method yielding an average grain size of approximately 50-70 nm, while the co-precipitation method result in an average grain size of about 40-60 nm. Leaching tests revealed that the smaller grain sizes are correlated with higher leaching rates. Furthermore, for ceramics with similar grain sizes, those with higher entropy values exhibited higher leaching rates. The increase in grain boundaries was found to reduce the leaching performance of the rare earth zirconate ceramics, and this effect became more pronounced with increasing entropy. This work provides insights into the selection of entropy values and grain sizes for the high-level radioactive waste matrices, which can be considered as a potential substrate for the simultaneous immobilization of multiple radionuclides.
摘要：
The phosphoric acid activated biochar adsorbent is recognized as a good candidate for application in efficient disposal of uranium-containing nuclear wastewaters. However, the production of high-efficiency biochars with typical characteristics of large specific surface area, hierarchically porous structure and abundant adsorption group remains a challenge. In this work, we report a new hydrogelation-carbonization technique to facilely produce phosphorus-doped biochar from pomelo peel and meantime provide new sights into the interaction mechanism of phosphoric acid groups with uranium ion. An interesting hydrogelation phenomenon is found when simply mixing the phosphoric acid solution and pomelo peel powder. The resulted hydrogel readily undergo carbonization to produce desired biochar. The biochar exhibits good uranium removal efficiency (up to 99 %) with a maximum adsorption capacity of 603 mg/g at 313 K. The distribution coefficient of uranium (VI) attains 10.8 L/g. The biochar undergoes five desorption-adsorption cycles with desorption and adsorption efficiencies above 95 %. It can be applied in fix-bed column for dynamic adsorption of uranium from uranium-containing solutions and real nuclear wastewater with an adsorption capacity over 422 mg/g. Rather than direct interaction with uranium ion, our experimental and computational results reveal that the surface phosphoric acid groups initially undergo in-situ ionization to produce phosphonates and the complexation of phosphonate with uranium ion results in effective uranium adsorption. This work demonstrates the high efficiency of pomelo peel biochar for disposal of uranium-containing nuclear wastewater, and offers new insights into the mechanism of uranium adsorption on the adsorbents containing phosphoric acid and phosphonate groups.
摘要：
The post-grafting of porous silica with organic group is a common method for the synthesis of organofunctionalized silica adsorbent. However, this method usually produces adsorbents with limited adsorption performances due to the pore blocking caused by the irregular introduction of organic group. In this work, we report the controllable synthesis of phosphoric acid functionalized porous silica adsorbent based on the cocondensation method for uranium (VI) adsorptive removal with enhanced adsorption performance. Characterizations of the obtained silica verify its porous structure and confirm the homogeneous distribution of phosphoric acid groups inside the silica. This silica is able to efficiently remove 98 % of uranium from a 100 mg/L uranium (VI) solution within 10 min at a dosage of 0.6 g/L and the maximum uranium (VI) adsorption amount reaches 509 mg/g. Both adsorption capacity and adsorption rate of this silica are superior than that of the silica synthesized based on conventional post-grafting method. Moreover, this silica can be reused for five times with uranium (VI) removal efficiency above 95 % and it is well applied in adsorption column for dynamically adsorptive removal of uranium (VI) from real nuclear wastewater. Mechanism-related investigations reveal that uranium (VI) adsorption on this silica proceeds by effective ion exchange of uranium (VI) ion with either phosphoric acid or silanol group and the formation of uranyl phosphonate or uranyl silicate complex. This work provides a feasible strategy to synthesize functionalized porous silica without significant pore blocking, and demonstrates the enhancement effect of regulating surface adsorption groups on the adsorption performances of porous silica. Besides, this work offers a promising adsorbent for efficient treatment of uranium-containing nuclear wastewater and reveals the mechanism of uranium adsorption on those silica adsorbent containing phosphoric acid, thiol or thioether group.
作者机构：
[Tang, Xian; Han, Hai] Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.;[Li, Le] Univ South China, Sch Publ Hlth, Hengyang 421001, Peoples R China.;[Wang, Hongqing] Univ South China, Sch Chem & Chem Engn, Hengyang 421001, Peoples R China.;[Wang, Hongqing] Univ South China, Hunan key Lab Design & Applicat Actinide Complexes, Hengyang 421001, Hunan, Peoples R China.
通讯机构：
[Tang, X ; Li, L ] U;Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.;Univ South China, Sch Publ Hlth, Hengyang 421001, Peoples R China.
通讯机构：
[Yue, CT ] U;Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.
关键词：
Poly(vinylphosphonic acid);POSS;Limited swelling capacity;Bath and column modes;Uranium (VI) removal
摘要：
Organophosphorus acid polymers with high hydrophilicity and limited swelling capacity have great application potential in disposal of uranium (VI)-containing wastewater due to its high uranium (VI) adsorption efficiency. In this work, POSS-crosslinked poly(vinylphosphonic acid) polymer is synthesized via copolymerization of octa-vinyloctasilasesquioxane and vinylphosphonic acid for uranium (VI) adsorptive removal from solution. The polymer has a high hydrophilicity and limited swelling capacity. The uranium (VI) adsorptive removal is per-formed in batch mode and the effects of polymer dosage, pH and ionic strength are investigated. The polymer shows high removal efficiency for uranium (VI) from a 120 mg L-1 solution and can achieve the complete uranium (VI) removal at 30 degrees C and pH 4.0 with 0.33 g L-1 polymer. The adsorption process is analyzed by comparison with the adsorption kinetic and isotherm models. Uranium (VI) adsorption on this polymer is found to be more consistent with the pseudo-second-order and Langmuir models, and the maximum adsorption ca-pacity attains 714 mg g- 1. Competitive adsorption between uranium (VI) and other metal ions on polymer is performed to analyse the adsorption selectivity. The polymer attains a 20 L g- 1 uranium (VI) distribution co-efficient, higher than other metal ions (0.1-1.8 L g-1). The polymer can be easily recycled for at least five times with removal efficiency above 99% and the polymer can be well applied for dynamic adsorptive removal of uranium (VI) from uranium-containing solution (5 mg L-1) in a fixed-bed column with removal efficiency above 99%. The excellent uranium (VI) removal performances of this composite polymer highlight its great potential in the disposal of uranium-containing nuclear wastewater.
通讯机构：
[Wang, Hongqing; Liao, Yun] H;[Wang, Meng] S;Hunan key laboratory for the design and application of actinide complexes, University of South China, Hengyang, Hunan 421001, PR China. Electronic address:;School of Nuclear Science and Technology, University of South China, Hengyang, Hunan 421001, China. Electronic address:;Hunan key laboratory for the design and application of actinide complexes, University of South China, Hengyang, Hunan 421001, PR China. Electronic address:
通讯机构：
[Hong Wang] S;School of Resources, Environmental and Safety Engineering, University of South China, Hengyang, China<&wdkj&>School of Nuclear Science and Technology, University of South China, Hengyang, China<&wdkj&>Hunan Province Engineering Technology Research Center of Uranium Tailings Treatment, University of South China, Hengyang, China
关键词：
charcoal;radon;adsorption;Article;biomass;carbonization;chemical composition;chemical structure;concentration (parameter);grapefruit;mathematical computing;nonhuman;pore size;pyrolysis;rice husk;scanning electron microscopy;sugarcane
期刊：
Korean Journal of Chemical Engineering,2023年40(1):255-266 ISSN：0256-1115
通讯作者：
Qingliang Wang<&wdkj&>Lechang Xu
作者机构：
[Zhao, Xu] Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Hunan, Peoples R China.;[Wang, Hongqiang; Hu, Fang; Su, Yucheng; Wang, Qingliang; Fan, Shiyao; Liu, Xinwei; Hao, Xuanzhang; Hu, Eming; Lei, Zhiwu] Univ South China, Sch Resource Environm & Safety Engn, Hengyang 421001, Hunan, Peoples R China.;[Lei, Zhiwu] East China Univ Technol, State Key Lab Nucl Resources & Environm, Nanchang 330013, Jiangxi, Peoples R China.;[Xu, Lechang] CNNC, Beijing Res Inst Chem Engn & Met, Tongzhou Dist, Beijing 101149, Peoples R China.
通讯机构：
[Qingliang Wang] S;[Lechang Xu] B;School of Resource Environment and Safety Engineering, University of South China, Hengyang, Hunan, China<&wdkj&>Beijing Research Institute of Chemical Engineering and Metallurgy, CNNC, Beijing, China
摘要：
Purpose: This study aimed to evaluate whether high-energy X-rays (HEXs) of the PARTER (platform for advanced radiotherapy research) platform built on CTFEL (Chengdu THz Free Electron Laser facility) can produce ultrahigh dose rate (FLASH) X-rays and trigger the FLASH effect. Materials and methods: EBT3 radiochromic film and fast current transformer (FCT) devices were used to measure absolute dose and pulsed beam current of HEXs. Subcutaneous tumor-bearing mice and healthy mice were treated with sham, FLASH, and conventional dose rate radiotherapy (CONV), respectively to observe the tumor control efficiency and normal tissue damage. Results: The maximum dose rate of HEXs of PARTER was up to over 1000 Gy/s. Tumor-bearing mice experiment showed a good result on tumor control (p < 0.0001) and significant difference in survival curves (p < 0.005) among the three groups. In the thorax-irradiated healthy mice experiment, there was a significant difference (p = 0.038) in survival among the three groups, with the risk of death decreased by 81% in the FLASH group compared to that in the CONV group. The survival time of healthy mice irradiated in the abdomen in the FLASH group was undoubtedly higher (62.5% of mice were still alive when we stopped observation) than that in the CONV group (7 days). Conclusion: This study confirmed that HEXs of the PARTER system can produce ultrahigh dose rate X-rays and trigger a FLASH effect, which provides a basis for future scientific research and clinical application of HEX in FLASH radiotherapy. (C) 2021 The Authors. Published by Elsevier B.V.
通讯机构：
[Hai Wang] S;[Jian Zheng] N;National Institute of Radiological Sciences, National Institutes for Quantum Science and Technology, 491 Anagawa, Inage, Chiba, 263-8555, Japan<&wdkj&>School of Nuclear Science and Technology, University of South China, Hengyang, 421001, China<&wdkj&>National Institute of Radiological Sciences, National Institutes for Quantum Science and Technology, 491 Anagawa, Inage, Chiba, 263-8555, Japan
摘要：
<jats:title>Abstract</jats:title><jats:p>In order to enhance the controlled‐release property of starch‐based polyurethane (SPU) coating, polyurethane/montmorillonite (SPU/MMT) composite coatings for controlled‐release urea were prepared by in‐situ polymerization with a rotating drum. The effect of MMT on morphology, structure, physico‐chemical properties, especially controlled‐release property of the as‐prepared composite coatings were studied in detail. The results showed that MMT particles dispersed well in SPU matrix, and the obtained SPU/MMT composite coatings possessed more tough and compact morphology with less‐visible holes compared with SPU coating. With the content of MMT rising to 3%, the time needed for 75% nitrogen release increased to 49 days, much longer than 14 days of SPU coating. Further, the nitrogen release mechanism underlying the structure and properties of SPU/MMT composite coatings were discussed and elucidated. According to the analysis, the superior controlled‐release property of SPU/MMT coatings originated from the impermeablity to water molecules of layered MMT acting as mechanical barriers to increase the diffusion path and resistance, the enhanced crosslinking density and hydrophobicity of composite system due to the introduction of MMT, as well as the improved mechanical properties hindering the formation of cracks and enlargement of the holes on the surface of composite coatings.</jats:p>
期刊：
INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS,2021年111(3):S33 ISSN：0360-3016
通讯作者：
F. Gao
作者机构：
[Gao, F.; Zhang, Y.; Feng, G.; Dai, T.; Du, X.; Lin, B.; Li, J.] Univ Elect Sci & Technol China, Mianyang Cent Hosp, Sch Med, Dept Oncol, Mianyang, Sichuan, Peoples R China.;[Yang, Y.] China Acad Engn Phys, Inst Nucl Phys & Chem, Mianyang, Sichuan, Peoples R China.;[Zhu, H.] Sun Yat Sen Univ, Dept Radiat Oncol, Collaborat Innovat Ctr Canc Med, State Key Lab Oncol South China,Canc Ctr, Guangzhou, Peoples R China.;[Zhou, K.; Wang, H.; Shan, L.; Wang, J.; Xiao, D.; Chen, M.; Zhou, Z.; Li, M.; Li, P.; Wu, D.; Sheng, X.; Lu, Y.; Lao, C.; Yan, L.; Zhao, J.] China Acad Engn Phys, Inst Appl Elect, Mianyang, Sichuan, Peoples R China.;[Xie, G.; Ke, Q.] Univ Elect Sci & Technol China, Mianyang Cent Hosp, Sch Med, Dept Pathol, Mianyang, Sichuan, Peoples R China.
通讯机构：
[F. Gao] D;Departmant of Oncology, Mianyang Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Mianyang, China
摘要：
Ultrahigh dose-rate (FLASH) radiotherapy has attracted immense attention because of its tumor control efficiency and healthy tissue protection during preclinical experiments with electrons, kilo-voltage X-rays, and protons. Using high-energy X-rays (HEXs) in FLASH is advantageous owing to its deep penetration, small divergence, and cost-effectiveness. We did this experiment to find out whether PARTER (platform for advanced radiotherapy research) platform built on CTFEL (Chengdu THz Free Electron Laser facility) can trigger FLASH effect.
Subcutaneous tumor-bearing mice and healthy mice were treated with sham, FLASH, and conventional (CONV) radiotherapy respectively to observe the tumor control and normal tissue damage under different radiation conditions. With a high-current and high-energy superconducting linear accelerator, FLASH with a good dose rate and high penetration was achieved. Breast cancers artificially induced in BAL b/c mice were efficiently controlled, and normal tissues surrounding the thorax/abdomen in C57BL/6 mice were protected from radiation with HEX-FLASH (HEX with FLASH). Theoretical analyses of cellular responses following HEX-FLASH irradiation were performed to interpret the experimental results and design further experiments.
HEX-FLASH was implemented using the superconducting LINAC with the maximum mean dose rate up to over 1000 Gy/s. Tumor-bearing mice experiment showed a good result on tumor control (F = 25.14, P < 0.0001) and significantly different in survival curves (P < 0.005) among the three groups. In the thorax-irradiated healthy mice experiment, there was a statistically significant difference (P = 0.038) in survival among the three groups. The hazard ratio (HR) was 0.19, 95% confidence intervals (CIs) was 0.035–1.010, and P was 0.0486 between the FLASH and CONV groups; therefore, the risk of death decreased by 81% in the FLASH group compared with that in the CONV group. Although the survival time of healthy mice irradiated on abdomen in the FLASH group was undoubtedly higher (62.5 % of mice were still alive when we stopped observation) than that in the CONV group (7 days), the difference in survival between the two groups was not statistically significant (HR 0.369; 95% CI 0.113–1.202; P = 0.0735). Despite this, the survival trend of mice treated with HEX-FLASH radiotherapy was better. We demonstrated theoretical cellular response analysis of the FLASH effect based on the ROD hypothesis and it showed consistent radioprotective effects in normal cells under FLASH irradiation.
This study highlights the generation of HEX-FLASH for the first time and its potential in future clinical applications.
