Recent Advances in Heterostructured Photocatalysts for Degradation of Organic Pollutants.

Author(s):  
Chen-Jing Sun ◽  
Li-Ping Zhao ◽  
Rui Wang

: With the development of industrialization, the global environmental pollution and energy crisis are becoming increasingly serious. Organic pollutants pose a serious health threat to human beings and other organisms. The removal of organic pollutants in environment has become a global challenge. The photocatalytic technology has been widely used in the degradation of organic pollutants with its characteristics of simple process, high efficiency, thorough degradation and no secondary pollution. However, the single photocatalyst represented by TiO2 has disadvantages of low light utilization rate and high recombination rate of photocarriers. Building heterojunction is considered one of the most effective methods to enhance the photocatalytic performance of single photocatalyst, which can improve the separation efficiency of photocarriers and utilization of visible light. The classical heterojunction can be divided into four different cases: type I, typeⅡ, p–n heterojunctions and Z-scheme junction. In this paper, the recent progress in the treatment of organic pollution by heterostructure photocatalysts is summarized and the mechanism of heterostructure photocatalysts for the treatment of organic pollutants is reviewed. It is expected that this paper can deepen the understanding of heterostructure photocatalysts and provide guidance for high efficient photocatalytic degradation of organic pollutants in the future.

2019 ◽  
Vol 13 ◽  
Author(s):  
Haisheng Li ◽  
Wenping Wang ◽  
Yinghua Chen ◽  
Xinxi Zhang ◽  
Chaoyong Li

Background: The fly ash produced by coal-fired power plants is an industrial waste. The environmental pollution problems caused by fly ash have been widely of public environmental concern. As a waste of recoverable resources, it can be used in the field of building materials, agricultural fertilizers, environmental materials, new materials, etc. Unburned carbon content in fly ash has an influence on the performance of resource reuse products. Therefore, it is the key to remove unburned carbon from fly ash. As a physical method, triboelectrostatic separation technology has been widely used because of obvious advantages, such as high-efficiency, simple process, high reliability, without water resources consumption and secondary pollution. Objective: The related patents of fly ash triboelectrostatic separation had been reviewed. The structural characteristics and working principle of these patents are analyzed in detail. The results can provide some meaningful references for the improvement of separation efficiency and optimal design. Methods: Based on the comparative analysis for the latest patents related to fly ash triboelectrostatic separation, the future development is presented. Results: The patents focused on the charging efficiency and separation efficiency. Studies show that remarkable improvements have been achieved for the fly ash triboelectrostatic separation. Some patents have been used in industrial production. Conclusion: According to the current technology status, the researches related to process optimization and anti-interference ability will be beneficial to overcome the influence of operating conditions and complex environment, and meet system security requirements. The intelligent control can not only ensure the process continuity and stability, but also realize the efficient operation and management automatically. Meanwhile, the researchers should pay more attention to the resource utilization of fly ash processed by triboelectrostatic separation.


Author(s):  
Victoria Teniola Adeleke ◽  
Adebayo A Adeniyi ◽  
David Lokhat

Availability of clean water for various activities is a global challenge. Moringa oleifera (MO) seed protein extract has been identified as a natural coagulant for wastewater treatment. The mechanistic understanding...


2021 ◽  
Author(s):  
Luqiu Li ◽  
Dongguang Yin ◽  
Xiandi Guo

Covalent organic frameworks (COFs) representing an emerging class of porous crystalline material have shown promising visible-light-driven hydrogen evolution activity. However, they have a high recombination ratio of charge carriers and...


2017 ◽  
Vol 8 (2) ◽  
pp. 870-875
Author(s):  
M. J. Zhang ◽  
R. R. Zhang ◽  
G. Xu ◽  
L. P. Chen

Problems in the process of manned agricultural aerial spraying, such as heavy workload in route planning, overlaps or omissions in spraying seriously reduce the efficiency of spraying and utilization rate of pesticides. This paper presents the design and development of a navigation system for manned agricultural aerial spraying based on an industrial tablet PC. This system provides three key functions: route planning, spraying navigation and real-time evaluation of spraying quality. The test and application results show that this system has high efficiency in route planning, and the average coverage rate of spraying could reach as high as 96%. Its application effect is remarkable, and as a result, this system can meet the demand of manned agricultural aerial spraying in route planning and navigation.


Author(s):  
Aya Mabrouki ◽  
Mohamed Latrach

This chapter proposes an overview of microwave energy harvesting with focuses on the design of high efficiency low power rectifying circuits. A background survey of RF energy harvesting techniques is presented first. Then, the performances of conventional rectifier topologies are analyzed and discussed. A review of the most efficient rectenna designs, from the state of the art, is also presented. Design considerations for low power rectifier operations are detailed and new high efficient rectifying circuits are designed and evaluated in both GSM and ISM bands under low power constraints.


2019 ◽  
Vol 3 (122) ◽  
pp. 59-71
Author(s):  
Volodymyr Serhiiovych Hryshyn ◽  
Serhii Oleksiiovych Abramov

Technological possibilities of jet processing cause increased attention to the study of the regularities of the process. The main interest for practice is the establishment of the kind of dependencies between technological parameters (abrasive particles size, particle speed, concentration, compressed air pressure, attack angle, physical and mechanical properties of particles and surface to be treated) and initial process parameters (roughness of the treated surface, removal rates of the metal and libel). That, in turn, determines the necessity of optimal choice of the values of technological parameters in the conditions of a concrete production situation. The basic regularities can be established as a result of regression analysis of experimental data. However, the use of the resulting laws is limited to the complexity of the process and relatively narrow areas of changing the parameters of the experiment.The purpose of the work is to determine the factors that determine the formation of a microrelief in the area of the abrasive air jet, the relationship between them and the degree of their effect on the intensity of the formation of a microrelief; formation of a model of finishing treatment of collector plates, creation of theoretical bases and methodology of designing high-efficient resource-saving technological processes of production of motor collectors of electric machines.Analysis of recent research and publications. The following contributions were made to the development of the theory of modeling of the inkjet-abrasive surface treatment: Volovetsky O.E., Denysyuk V.Yu., Kharchik M.M., Buts BP, Andilahi A.A., Novikov FV, Gordeyev AI, Urbanyuk Ye.A., Silin R.S. and other.The most universal approach based on determining the search dependencies and solving the problem of optimizing the technological parameters of the processing process as a result of statistical simulation, namely the ability to control the input parameters before the start of the model or in the process of work - one of the key benefits of using simulation modeling for the analysis of systems and processes. This allows you to determine the optimal parameters, which maximize the efficiency of the processes, determine the relationship between the input and output parameters.The paper considers: creation of theoretical bases and methodology of designing high-efficiency resource-saving technological processes of production of motor collectors of electric machines; the process of formation of microrelief of collector plates in the area of the abrasive air jet, the relationship between the factors and the degree of their influence on the intensity of formation. The formation of a model of finishing treatment of collector plates treated with silicon carbide (black) was determined.Prospects for further research are the improvement of the technological process of obtaining collector nodes on the possibilities of implementation.


2021 ◽  
Vol 8 ◽  
Author(s):  
Michiel Van de Voorde ◽  
Charlotte Duchemin ◽  
Reinhard Heinke ◽  
Laura Lambert ◽  
Eric Chevallay ◽  
...  

Samarium-153 (153Sm) is a highly interesting radionuclide within the field of targeted radionuclide therapy because of its favorable decay characteristics. 153Sm has a half-life of 1.93 d and decays into a stable daughter nuclide (153Eu) whereupon β− particles [E = 705 keV (30%), 635 keV (50%)] are emitted which are suitable for therapy. 153Sm also emits γ photons [103 keV (28%)] allowing for SPECT imaging, which is of value in theranostics. However, the full potential of 153Sm in nuclear medicine is currently not being exploited because of the radionuclide's limited specific activity due to its carrier added production route. In this work a new production method was developed to produce 153Sm with higher specific activity, allowing for its potential use in targeted radionuclide therapy. 153Sm was efficiently produced via neutron irradiation of a highly enriched 152Sm target (98.7% enriched, σth = 206 b) in the BR2 reactor at SCK CEN. Irradiated target materials were shipped to CERN-MEDICIS, where 153Sm was isolated from the 152Sm target via mass separation (MS) in combination with laser resonance enhanced ionization to drastically increase the specific activity. The specific activity obtained was 1.87 TBq/mg (≈ 265 times higher after the end of irradiation in BR2 + cooling). An overall mass separation efficiency of 4.5% was reached on average for all mass separations. Further radiochemical purification steps were developed at SCK CEN to recover the 153Sm from the MS target to yield a solution ready for radiolabeling. Each step of the radiochemical process was fully analyzed and characterized for further optimization resulting in a high efficiency (overall recovery: 84%). The obtained high specific activity (HSA) 153Sm was then used in radiolabeling experiments with different concentrations of 4-isothiocyanatobenzyl-1,4,7,10-tetraazacyclododecane tetraacetic acid (p-SCN-Bn-DOTA). Even at low concentrations of p-SCN-Bn-DOTA, radiolabeling of 0.5 MBq of HSA 153Sm was found to be efficient. In this proof-of-concept study, we demonstrated the potential to combine neutron irradiation with mass separation to supply high specific activity 153Sm. Using this process, 153SmCl3 suitable for radiolabeling, was produced with a very high specific activity allowing application of 153Sm in targeted radionuclide therapy. Further studies to incorporate 153Sm in radiopharmaceuticals for targeted radionuclide therapy are ongoing.


Minerals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 2 ◽  
Author(s):  
Qian Peng ◽  
Xuekun Tang ◽  
Kun Liu ◽  
Xianping Luo ◽  
Dongsheng He ◽  
...  

In the study, magnesium oxide (MgO) was used to catalyze peroxymonosulfate (PMS) for the degradation of organic pollutants for the first time. According to the single-factor experiment results, it was determined that MgO could efficiently catalyze PMS to degrade organic matters in a wide range of pH values. Based on radical quenching experiments and electron spinning resonance spectra, singlet oxygen was identified to be the crucial reactive species. Importantly, the oxygen vacancy on the surface of MgO was determined as the key active site, which accelerated the decomposition of PMS to produce singlet oxygen. This study provides an interesting insight into the novel and ignored catalyst of MgO for the highly efficient activation of PMS, which will greatly benefit the Fenton-like catalytic degradation of organic wastewater.


Catalysts ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 981 ◽  
Author(s):  
Zexuan Wang ◽  
Kunfeng Zhao ◽  
Bei Xiao ◽  
Peng Gao ◽  
Dannong He ◽  
...  

Monolithic catalysts have great industrial application prospects compared to powdered catalysts due to their low pressure drop, the high efficiency of mass and heat transfer, and recyclability. Deposition of active phases on the monolithic carriers dramatically increases the utilization rate and has been attracting continuous attention. In this paper, we reviewed the traditional (impregnation, coating, and spraying) and novel (hydrothermal and electrodeposition) strategies of surface deposition integration, analyzed the advantages and disadvantages of both ways, and then prospected the possible directions for future development of integration technologies.


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