Journal of Environmental Chemical Engineering
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2024
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IF 7.4
Zengkai Song,Chunpei Yan,Jialin Qiu,Chao Liu,Ye'an Zhu,Bo Wang,Zongbo Xie,Guo Chen,Kangqiang Li,Zhanggao Le
Graphitic carbon nitride (g-C 3 N 4 ) has garnered significant attention in the realm of photocatalytic reduction of U(Ⅵ) from aqueous solutions owing to its favorable bandgap and visible light responsiveness. Nevertheless, conventionally prepared bulk g-C 3 N 4 suffers from limitations such as a small specific surface area and high recombination of photo-generated charges, consequently impeding the efficiency of photocatalytic reactions and hampering practical applications. To address these shortcomings, this study presents a novel approach wherein ultra-thin porous g-C 3 N 4 nanosheets were successfully synthesized through the microwave-assisted calcination of urea in a single step. The resulting g-C 3 N 4 nanosheets exhibit a multi-hollow mesh structure with a significantly enlarged specific surface area, the specific surface area and pore size of MCN 90 are 170 m²/g and 17 nm, respectively, which are 2.3 times and 8 times that of the bulk g-C 3 N 4 . Photocatalytic experiments revealed that these ultra-thin porous nanosheets demonstrate superior performance in the reduction of U(Ⅵ) to U(Ⅳ), achieving a reduction rate of 100 % within 20 minutes for the optimal sample, as opposed to 78 % in 40 minutes for bulk g-C 3 N 4 . This enhanced photocatalytic activity can be primarily attributed to the unique ultra-thin porous nanosheet structure, which facilitates increased specific surface areas, improve photoelectric properties, and substantially shortened electron migration distances which reduce the recombination efficiency of photogenerated electrons and holes pairs. Consequently, these findings not only offer insights into the optimization of g-C 3 N 4 for U(Ⅵ) reduction but also provide a valuable reference for the preparation of other two-dimensional ultra-thin porous materials aimed at similar applications.
研究领域:
材料科学
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环境科学
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产品关联
DOI
高影响因子
Materials Today Communications
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2024
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IF 3.7
Chuanyi Ma,Zhanguo Li,Yi Wang
Hydrogel is an effective surface radioactive decontamination technology. However, traditional colloid decontaminants face long curing duration and low decontamination rate issues. A peelable hydrogel coating composed of carrageenan, konjac glucan, and graphene oxide (GO) with excellent film-forming performance and decontamination efficiency was explored in this study. The results showed that the GO was effectively dispersed inside the hydrogel, improving the crosslink density and thermal stability of the hydrogel by forming hydrogen bonds with polysaccharide molecules. The GO can effectively enhance the decontamination performance of the hydrogel. For stainless steel, ceramic, glass, and rubber surfaces, the decontamination rates of the hydrogel for 30 min were 96.95 %, 87.6 %, 96.27 %, and 74.5 %, respectively. Furthermore, the decontamination effect was stable to temperature. For cement surfaces, the hydrogel could reach a maximum decontamination rate of 70.68 % after 24 h. The decontamination efficiency of hydrogel was affected by porosity, surface roughness, and GO addition. Moreover, the characterization results of XPS, FT-IR, and SEM/EDS showed that the decontamination process of the composite hydrogel may involve surface wetting, ion diffusion, electrostatic attraction, and physical entanglement. In conclusion, the as-prepared hydrogel has been demonstrated as a green, cost-effective surface decontaminant, which has great potential in the field of nuclear industry fields and environmental remediation.
研究领域:
环境科学
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材料科学
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核工程
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DOI
高影响因子
CHEMOSPHERE
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2023
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IF 8.8
Yong Zhang,Siqi Huang,Bingyu Mei,Xiaoyu Tian,Lingyi Jia,Nan Sun
As a novel adsorbent for the separation of uranium(VI) from wastewater, Magnetite/β-cyclodextrin/fly ash composite (Fe 3 O 4 /β-CD/FA) was first prepared via a chemical coprecipitation technology . The characterization results indicated that Fe 3 O 4 and β-CD had been successfully loaded on FA, which had brought abundant oxygen-containing functional groups, providing numerous adsorptive sites for the removal of uranium(VI). At pH = 5.0 and T = 25 °C, the maximum uranium(VI) removal efficiency and capacity of Fe 3 O 4 /β-CD/FA were higher to 97.8% and 444.4 mg g −1 , respectively. Pseudo-second-order and Langmuir models fitted better with the experimental data, illustrating that chemical adsorption dominated the uranium(VI) removal process. In addition, Fe 3 O 4 /β-CD/FA showed good anti-interference ability and recoverability . After five cycles, the removal rate of uranium(VI) on Fe 3 O 4 /β-CD/FA was still higher to 90.4%. The immobilization of uranium(VI) on Fe 3 O 4 /β-CD/FA was mainly ascribed to the synergism of redox reaction, complex reaction, chemical reaction and electrostatic interaction. Given the above, Fe 3 O 4 /β-CD/FA would be regarded as an efficacious, green and promising adsorbent for uranium(VI) separation from wastewater.
研究领域:
环境科学
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材料科学
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化学工程
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DOI
PubMed
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2024
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IF 4.9
Chuanyi Ma,Jian Li,Yi Wang,Zhanguo Li
Hydrogels have attracted widespread attention in the field of surface radioactivity decontamination due to their mild and rapid decontamination processes, as well as their tunable properties. However, fabricating decontamination hydrogels with suitable mechanical properties and environmental adaptability remains challenging. In this study, a tough and freeze-resistant hydrogel (PEAG) was prepared based on graphene oxide (GO), polyvinyl alcohol (PVA), agar (AG), and ethylene glycol (EG) for efficient removal of surface radioactive uranium (VI). Due to the dynamic action of borax and the formation of a nanocomposite dual-network structure, PEAG possesses improved modulus and excellent self-healing properties, allowing the hydrogel to be easily applied to surfaces and to perform operations such as stretching and peeling. In addition, it is found that the PEAG achieves excellent decontamination rates for radioactive uranium (VI) on glass (88.53±1.43 %), stainless steel (86.72±3.41 %), rubber (67.0±2.43 %), ceramics (82.39±1.78 %), and cement (64.52±1.72 %) surfaces, respectively. XPS and contact angle experiments demonstrated that the improved decontamination performance of PEAG is mainly due to the abundant hydroxyl and carbonyl functional groups in the graphene oxide adsorbent, which provide a rich source of complexation sites and enhance its hydrophilic properties for PEAG. Additionally, due to the incorporation of EG, the PEAG hydrogel exhibits good environmental adaptability, which can retain internal moisture and maintain softness and decontamination stability at low temperatures of −20°C. Therefore, PEAG hydrogel is a promising and sustainable candidate material for various surface radioactive decontamination scenarios.
研究领域:
材料科学
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环境科学
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核工程
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化学
✓ 已验证
产品关联
DOI
高影响因子
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