Na Zhang

Bio: Na Zhang is an academic researcher from Shanghai Institute of Technology. The author has contributed to research in topics: Photocatalysis & Materials science. The author has an hindex of 13, co-authored 34 publications receiving 448 citations.

Adsorption of Uranyl ions on Amine-functionalization of MIL-101(Cr) Nanoparticles by a Facile Coordination-based Post-synthetic strategy and X-ray Absorption Spectroscopy Studies

Abstract: By a facile coordination-based post-synthetic strategy, the high surface area MIL-101(Cr) nanoparticles was functionallized by grafting amine group of ethylenediamine (ED) on coordinatively unsaturated Cr(III) centers, yielding a series of ED-MIL-101(Cr)-based adsorbents and their application for adsorption of U(VI) from aqueous solution were also studied. The obtained ED-functionallized samples with different ED contents were characterized by powder X-ray diffraction (PXRD), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), FTIR, elemental analysis (EA) and N2 adsorption and desorption isothermal. Compared with the pristine MIL-101(Cr) sorbents, the ED-functionallized MIL-101(Cr) exhibits significantly higher adsorption capacity for U(VI) ions from water with maximum adsorption capacities as high as 200 mg/g (corresponding to 100% extraction rate) at pH of 4.5 with ED/Cr ratio of 0.68 and the sorbed U(VI) ions can easily be desorbed at lower pH (pH ≤ 2.0). The adsorption mode of U(VI) ions and effects of grafted ED on the MIL-101(Cr) frameworks were also been studied by X-ray absorption spectroscopy (XAS). We believe that this work establishes a simple and energy efficient route to a novel type of functional materials for U(VI) ions extraction from solution via the post-synthetic modification (PSM) strategy.

A visible-light driven Bi2S3@ZIF-8 core–shell heterostructure and synergistic photocatalysis mechanism

Abstract: Visible-light-driven organic transformations have received much attention because of their low cost, relative safety, and environmental friendliness. In this work, we report a series of Bi2S3@ZIF-8 core–shell heterostructures prepared using a simple and efficient self-assembly process. The photocatalytic activity was evaluated using the photocatalytic degradation of Rhodamine B (RhB) under visible-light irradiation and the results show that the core–shell Bi2S3@ZIF-8 heterostructure can remarkably enhance the photocatalytic efficiency at room temperature compared to pristine Bi2S3 nanorods. In addition, the Bi2S3@ZIF-8 composite with a Bi/Zn molar ratio of 1/10 demonstrates good structural stability after the degradation experiment and its photocatalytic activity remains at about 95% after the five recycling tests. The improved photocatalytic performance can be attributed to the larger specific surface area, increased light absorption, and more efficient separation of photogenerated electron–hole pairs due to the combined effects of Bi2S3 and ZIF-8. Moreover, the synergistic photocatalysis mechanism was investigated.

Heterostructural Ag3PO4/UiO-66 composite for highly efficient visible-light photocatalysts with long-term stability

Abstract: To aim to extent the advantage of the high optical absorbance and overcome the shortcoming of the instability on Ag3PO4, a novel visible-light-driven heterostructure photocatalyst Ag3PO4/UiO-66 (APU) composite with a synergistic effect of adsorption enrichment and photocatalysis degradation has been successfully fabricated via a facile chemical bath deposition method. The APU photocatalyst is not only favorable to increasing the absorption ability for organic pollutants owing to a larger surface area, but also promotes the separation and transformation of electron-hole pairs due to the good conductivity performance in the presence of Ag/Ag3PO4/UiO-66 structure. Under visible-light illumination, the APU-15% composite photocatalyst has exhibited the excellent removal capacity, and the degradation efficiency can be up to 100% in 18 min. The degradation constant are about 80 and 2.7 times higher than those of bare UiO-66 and Ag3PO4 for the removal of RhB in the dynamic system, respectively. The enhancement of removal efficiency is due to a synergistic effect of adsorption enrichment and photocatalysis degradation. The removal rate of the APU-15% composite photocatalyst has only 9.5% decrease for 5 cycles of the photoreaction, showing the relatively good stability. The trapping experiment and ESR show the main active species is O2 −. Furthermore, the photocatalytic mechanism has been proposed in the end.

World energy outlook

Abstract: This chapter discusses leading problems linked to energy that the world is now confronting and to propose some ideas concerning possible solutions. Oil deserves special attention among all energy sources. Since the beginning of 1981, it has merely been continuing and enhancing the downward movement in consumption and prices caused by excessive rises, especially for light crudes such as those from Africa, and the slowing down of worldwide economic growth. Densely-populated oil-producing countries need to produce to live, to pay for their food and their equipment. If the economic growth of the industrialized countries were to be 4%, even if investment in the rational use of energy were pushed to the limit and the development of nonpetroleum energy sources were also pursued actively, it would be extremely difficult to prevent a sharp rise in prices. It is evident that it is absolutely necessary to pursue actively the development of coal, natural gas, and nuclear power if a physical shortage of energy is not to block economic growth.

Metal–organic framework-based materials: superior adsorbents for the capture of toxic and radioactive metal ions

Abstract: Highly efficient removal of metal ion pollutants, such as toxic and nuclear waste-related metal ions, remains a serious task from the biological and environmental standpoint because of their harmful effects on human health and the environment. Recently, highly porous metal–organic frameworks (MOFs), with excellent chemical stability and abundant functional groups, have represented a new addition to the area of capturing various types of hazardous metal ion pollutants. This review focuses on recent progress in reported MOFs and MOF-based composites as superior adsorbents for the efficient removal of toxic and nuclear waste-related metal ions. Aspects related to the interaction mechanisms between metal ions and MOF-based materials are systematically summarized, including macroscopic batch experiments, microscopic spectroscopy analysis, and theoretical calculations. The adsorption properties of various MOF-based materials are assessed and compared with those of other widely used adsorbents. Finally, we propose our personal insights into future research opportunities and challenges in the hope of stimulating more researchers to engage in this new field of MOF-based materials for environmental pollution management.

Materials for the Recovery of Uranium from Seawater

Abstract: More than 1000× uranium exists in the oceans than exists in terrestrial ores. With nuclear power generation expected to increase over the coming decades, access to this unconventional reserve is a matter of energy security. With origins in the mid-1950s, materials have been developed for the selective recovery of seawater uranium for more than six decades, with a renewed interest in particular since 2010. This review comprehensively surveys materials developed from 2000–2016 for recovery of seawater uranium, in particular including recent developments in inorganic materials; polymer adsorbents and related research pertaining to amidoxime; and nanostructured materials such as metal–organic frameworks, porous-organic polymers, and mesoporous carbons. Challenges of performing reliable and reproducible uranium adsorption studies are also discussed, as well as the standardization of parameters necessary to ensure valid comparisons between different adsorbents.

Metal-Organic Frameworks for the Removal of Emerging Organic Contaminants in Water.

Abstract: Water is essential in all aspects of life, being the defining characteristic of our planet and even our body. Regrettably, water pollution is increasingly becoming a challenge due to novel anthropogenic pollutants. Of particular concern are emerging organic contaminants (EOCs), the term used not only to cover newly developed compounds but also compounds newly discovered as contaminants in the environment. Aside from anthropogenic contamination, higher temperature and more extreme and less predictable weather conditions are projected to affect water availability and distribution. Therefore, wastewater treatment has to become a valuable water resource and its reuse is an important issue that must be carried out efficiently. Among the novel technologies considered in water remediation processes, metal-organic frameworks (MOFs) are regarded as promising materials for the elimination of EOCs since they present many properties that commend them in water treatment: large surface area, easy functionalizable cavities, some are stable in water, and synthesized at large scale, etc. This review highlights the advances in the use of MOFs in the elimination (adsorption and/or degradation) of EOCs from water, classifying them by the nature of the contaminant.

State of the Art and Prospects for Halide Perovskite Nanocrystals.

Abstract: Metal-halide perovskites have rapidly emerged as one of the most promising materials of the 21st century, with many exciting properties and great potential for a broad range of applications, from photovoltaics to optoelectronics and photocatalysis. The ease with which metal-halide perovskites can be synthesized in the form of brightly luminescent colloidal nanocrystals, as well as their tunable and intriguing optical and electronic properties, has attracted researchers from different disciplines of science and technology. In the last few years, there has been a significant progress in the shape-controlled synthesis of perovskite nanocrystals and understanding of their properties and applications. In this comprehensive review, researchers having expertise in different fields (chemistry, physics, and device engineering) of metal-halide perovskite nanocrystals have joined together to provide a state of the art overview and future prospects of metal-halide perovskite nanocrystal research.