Research Progress on Photocatalytic/Photoelectrocatalytic Oxidation of Nitrogen Oxides

AbstractThe emission of nitrogen oxides (NOx) increases year by year, causing serious problems to our livelihoods. The photocatalytic oxidation of NOx has attracted more attention recently because of its efficient removal of NOx, especially for low concentrations of NOx. In this review, the mechanism of the photocatalytic oxidation of NOx is described. Then, the recent progress on the development of photocatalysts is reviewed according to the categories of inorganic semiconductors, bismuth-based compounds, nitrogen carbide polymer, and metal organic frameworks (MOFs). In addition, the photoelectrocatalytic oxidation of NOx, a method involving the application of an external voltage on the photocatalytic system to further increase the removal efficiency of NOx, and its progress are summarized. Finally, we outline the remaining challenges and provide our perspectives on the future directions for the photocatalytic oxidation of NOx.

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Removal efficiency of an integrated adsorption/photocatalysis system for reducing low concentrations of nitrogen oxides in microenvironments of museums for cultural relics conservation

Indoor and Built Environment ◽

10.1177/1420326x15592254 ◽

2016 ◽

Vol 25 (8) ◽

pp. 1185-1196 ◽

Cited By ~ 2

Author(s):

Dawei Wang ◽

Danian Zhang ◽

Yan Wu ◽

Hua Wei ◽

Jing Luo ◽

...

Keyword(s):

Nitrogen Oxides ◽

Removal Efficiency ◽

Photocatalytic Oxidation ◽

Removal Rate ◽

Nitrogen Monoxide ◽

Bamboo Charcoal ◽

Low Concentrations ◽

Integrated Device ◽

Direct Use ◽

Cultural Relics

Nitrogen oxides (NOx) could pose a threat to the conservation of cultural relics and could also enhance the corrosion induced by other pollutants such as sulphur dioxides and organic acids. The NOx removal rate was studied through a combination of adsorption onto bamboo charcoal and photocatalysis. The integrated NOx removal efficiency by both methods was evaluated in both lab and pilot scales. The studies have shown that the direct use of biomass can remove moderate level of NOx; while higher level of NOx removal was achieved by using bamboo charcoal carbonized at 520℃. The photocatalytic oxidation of NOx was found to be well fit with Langmuir–Hinshelwood model. The different carriers of photocatalysis combined with adsorbents were compared, and the optimised process was shown to reduce the nitrogen monoxide and nitrogen dioxide level to 2.76 and 0.68 µg/m3, respectively, in 20% relative humidity (RH). An integrated device was developed, and the results have demonstrated that the combined technologies of photocatalysis and adsorption can have great removal potential for reducing NOx and therefore in improving the air quality under different RH conditions.

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Mix Networks: Existing Scenarios and Future Directions on Security and Privacy

Recent Patents on Engineering ◽

10.2174/1872212114666191223125619 ◽

2019 ◽

Vol 14 ◽

Author(s):

Khaleel Ahmad ◽

Afsar Kamal

Keyword(s):

Security And Privacy ◽

Research Progress ◽

Future Research ◽

Future Directions ◽

Practical Solution ◽

Research Gap ◽

The Web ◽

Privacy Enhancing Techniques

Background: Privacy enhancing techniques are developed in order to provide strong protection to cyberspace. These techniques aim to allow users to keep their identities hidden during the communication when they are sending email, making payments online, browsing the Web or posting to newsgroups. MixNet is the most practical solution for concealing identities of message and sender’s identities. Objective: It provides sender and receiver anonymity as well as message security. The main goal of MixNet is to overcome vulnerability and enhance the performance of communication. It can efficiently handle the messages of various length and produce desirable results with privacy. The main objective of this paper is to acquire information and concepts regarding MixNet. We also provide guidelines for future research and references. Methods : The designing of MixNet depends on what cryptosystem method is used. Symmetric and Asymmetric both are used. Other methods could be also used such as PIR, CSP and FDR model, RPC, Token-based approach or others. Result: In this paper we provide an overview of MixNet approaches and presented a survey on MixNet based techniques and different models. We also constructed the comparison tables as per our requirements for better understanding. For this purpose, we found a total of 120 articles related to the MixNet published between 1990 and 2018 from the most relevant scientific resources. However, only 86 papers were analyzed due to comprehensiveness and relevancy to this article. Conclusion: Focused on the security and privacy of communication and how it can be achieved. This survey also reveals research progress and research gap on MixNet.

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Highly-Efficient Sulfonated UiO-66(Zr) Optical Fiber for Rapid Detection of Trace Levels of Pb2+

International Journal of Molecular Sciences ◽

10.3390/ijms22116053 ◽

2021 ◽

Vol 22 (11) ◽

pp. 6053

Author(s):

Marziyeh Nazari ◽

Abbas Amini ◽

Nathan T. Eden ◽

Mikel C. Duke ◽

Chun Cheng ◽

...

Keyword(s):

Optical Fiber ◽

Rapid Detection ◽

Chemical Sensor ◽

Metal Organic Framework ◽

Aqueous System ◽

Icp Oes ◽

Efficient Detection ◽

Low Concentrations ◽

Fabry Perot ◽

Metal Organic

Lead detection for biological environments, aqueous resources, and medicinal compounds, rely mainly on either utilizing bulky lab equipment such as ICP-OES or ready-made sensors, which are based on colorimetry with some limitations including selectivity and low interference. Remote, rapid and efficient detection of heavy metals in aqueous solutions at ppm and sub-ppm levels have faced significant challenges that requires novel compounds with such ability. Here, a UiO-66(Zr) metal-organic framework (MOF) functionalized with SO3H group (SO3H-UiO-66(Zr)) is deposited on the end-face of an optical fiber to detect lead cations (Pb2+) in water at 25.2, 43.5 and 64.0 ppm levels. The SO3H-UiO-66(Zr) system provides a Fabry–Perot sensor by which the lead ions are detected rapidly (milliseconds) at 25.2 ppm aqueous solution reflecting in the wavelength shifts in interference spectrum. The proposed removal mechanism is based on the adsorption of [Pb(OH2)6]2+ in water on SO3H-UiO-66(Zr) due to a strong affinity between functionalized MOF and lead. This is the first work that advances a multi-purpose optical fiber-coated functional MOF as an on-site remote chemical sensor for rapid detection of lead cations at extremely low concentrations in an aqueous system.

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Current Knowledge and Future Directions for Improving Subsoiling Quality and Reducing Energy Consumption in Conservation Fields

Agriculture ◽

10.3390/agriculture11070575 ◽

2021 ◽

Vol 11 (7) ◽

pp. 575

Author(s):

Shangyi Lou ◽

Jin He ◽

Hongwen Li ◽

Qingjie Wang ◽

Caiyun Lu ◽

...

Keyword(s):

Energy Consumption ◽

Cover Crops ◽

Current Knowledge ◽

High Energy ◽

Field Application ◽

Research Progress ◽

Monitoring And Control ◽

Future Directions ◽

Tillage Depth ◽

And Control

Subsoiling has been acknowledged worldwide to break compacted hardpan, improve soil permeability and water storage capacity, and promote topsoil deepening and root growth. However, there exist certain factors which limit the wide in-field application of subsoiling machines. Of these factors, the main two are poor subsoiling quality and high energy consumption, especially the undesired tillage depth obtained in the field with cover crops. Based on the analysis of global adoption and benefits of subsoiling technology, and application status of subsoiling machines, this article reviewed the research methods, technical characteristics, and developing trends in five key aspects, including subsoiling shovel design, anti-drag technologies, technologies of tillage depth detection and control, and research on soil mechanical interaction. Combined with the research progress and application requirements of subsoiling machines across the globe, current problems and technical difficulties were analyzed and summarized. Aiming to solve these problems, improve subsoiling quality, and reduce energy consumption, this article proposed future directions for the development of subsoiling machines, including optimizing the soil model in computer simulation, strengthening research on the subsoiling mechanism and comprehensive effect, developing new tillage depth monitoring and control systems, and improving wear-resisting properties of subsoiling shovels.

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