scholarly journals Natural lead-enriched biochar modifies TiO2 photocatalytic activation of sodium persulfate to degrade 2,4-dichlorophenol

2021 ◽  
Vol 233 ◽  
pp. 01111
Author(s):  
Xiangxin Lu ◽  
Wenbing Tan ◽  
Beidou Xi ◽  
Xiuyun Zhao
Keyword(s):  
Uv Light ◽  
Rapid Development ◽  
Advanced Oxidation ◽  
Ecological Environment ◽  
Sodium Persulfate ◽  
Active Sodium ◽  
Reaction Conditions ◽  
Combination System ◽  
Modern Chemical ◽  
Treatment Technologies

Due to the rapid development of the modern chemical industry, a large amount of chlorophenol pollutants remain in the environment. It poses a serious threat to the ecological environment and human health. Advanced oxidation technologies (AOPs) have the characteristics of mild reaction conditions and strong oxidation capacity, and are currently recognized as safe and effective pollutant treatment technologies. In this study, natural lead-rich biochar materials were used to activate sodium persulfate to degrade 2,4-dichlorophenol, and natural lead-rich biochar modified TiO2 photocatalytically degraded 2,4-dichlorophenol. Then, using natural lead-rich metal biochar/TiO2 material, photocatalysis combined with active sodium persulfate to degrade 2,4-dichlorophenol. The experimental results show that the combination of photocatalysis and activated sodium persulfate reaction can completely degrade 100 mg/L 2,4-dichlorophenol under UV light for 3 h, and the degradation efficiency is much higher than the sum of the two separate reactions. Quenching experiments show that SO4- • radicals play the most important role in the three free radicals (SO4- •, •OH and •O2- ) in the advanced oxidation combination system. Finally, the reaction mechanism of the two advanced oxidation combined systems are speculated.

Treatability of textile dye-bath effluents by advanced oxidation: preparation for reuse

1999 ◽  
Vol 40 (1) ◽  
pp. 183-190 ◽  
Author(s):  
N. H. Ince ◽  
G. Tezcanlı
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Azo Dye ◽  
Uv Light ◽  
Advanced Oxidation ◽  
Membrane System ◽  
Molar Ratio ◽  
Textile Dye ◽  
Experimental Conditions ◽  
Solids Content

Treatability of textile dye-bath effluents by advanced oxidation with Fenton and Fenton-like reagents (FeII/H2O2 and FeIII/H2O2), in the presence and absence of UV light was investigated, using a reactive azo-dye (Procion Red HE7B), and typical dye bath constituents. Under the experimental conditions employed, it was found that with 20 min UV irradiation, complete color removal and 79% total organic carbon degradation is possible, when the system is operated at pH=3, and with a H2O2/Fe(II) molar ratio of 20:1. The increased dissolved solids content of the treated solution implies the necessity of an appropriate membrane system to make the effluent reusable in the dye/wash processes.

scholarly journals Visible Light-Enabled Paternò-Büchi Reaction via Triplet Energy Transfer for the Synthesis of Oxetanes

2020 ◽  
Author(s):  
Katie Rykaczewski ◽  
Corinna Schindler
Keyword(s):  
Energy Transfer ◽  
Visible Light ◽  
Uv Light ◽  
Cycloaddition Reaction ◽  
High Energy ◽  
Triplet Energy ◽  
Reaction Conditions ◽  
Triplet Energy Transfer

<div> <p>One of the most efficient ways to synthesize oxetanes is the light-enabled [2+2] cycloaddition reaction of carbonyls and alkenes, referred to as the Paternò-Büchi reaction. The reaction conditions for this transformation typically require the use of high energy UV light to excite the carbonyl, limiting the applications, safety, and scalability. We herein report the development of a visible light-mediated Paternò-Büchi reaction protocol that relies on triplet energy transfer from an iridium-based photocatalyst to the carbonyl substrates. This mode of activation is demonstrated for a variety of aryl glyoxylates and negates the need for both, visible light-absorbing carbonyl starting materials or UV light to enable access to a variety of functionalized oxetanes in up to 99% yield.</p> </div> <br>

scholarly journals Recent Advances in Dynamic Modeling and Process Control of PVA Degradation by Biological and Advanced Oxidation Processes: A Review on Trends and Advances

Environments ◽  
2021 ◽  
Vol 8 (11) ◽  
pp. 116
Author(s):  
Yi-Ping Lin ◽  
Ramdhane Dhib ◽  
Mehrab Mehrvar
Keyword(s):  
Wastewater Treatment ◽  
Process Control ◽  
Dynamic Modeling ◽  
Reaction Mechanisms ◽  
Industrial Wastewater ◽  
Advanced Oxidation Processes ◽  
Advanced Oxidation ◽  
Oxidation Processes ◽  
Treatment Technologies ◽  
And Control

Polyvinyl alcohol (PVA) is an emerging pollutant commonly found in industrial wastewater, owing to its extensive usage as an additive in the manufacturing industry. PVA’s popularity has made wastewater treatment technologies for PVA degradation a popular research topic in industrial wastewater treatment. Although many PVA degradation technologies are studied in bench-scale processes, recent advancements in process optimization and control of wastewater treatment technologies such as advanced oxidation processes (AOPs) show the feasibility of these processes by monitoring and controlling processes to meet desired regulatory standards. These wastewater treatment technologies exhibit complex reaction mechanisms leading to nonlinear and nonstationary behavior related to variability in operational conditions. Thus, black-box dynamic modeling is a promising tool for designing control schemes since dynamic modeling is more complicated in terms of first principles and reaction mechanisms. This study seeks to provide a survey of process control methods via a comprehensive review focusing on PVA degradation methods, including biological and advanced oxidation processes, along with their reaction mechanisms, control-oriented dynamic modeling (i.e., state-space, transfer function, and artificial neural network modeling), and control strategies (i.e., proportional-integral-derivative control and predictive control) associated with wastewater treatment technologies utilized for PVA degradation.

scholarly journals Water Purification by Activation Plasma Technology

2020 ◽  
Vol 6 (8) ◽  
pp. 15-23
Keyword(s):  
Water Treatment ◽  
Liquid Water ◽  
Drinking Water Treatment ◽  
Advanced Oxidation ◽  
Throughput Capacity ◽  
Chemical Processing ◽  
Plasma Production ◽  
Plasma Injection ◽  
Treatment Technologies ◽  
Current Water

In modern water treatment technologies Water needs to be processed to a level that can be reused in a meaningful way. Plasma production or plasma injection in liquid water provides an opportunity to inject advanced Oxidation processes in water for purification or chemical processing. Such technology can revolutionize Drinking water treatment, as well as current practices of chemical processing by removing physical catalysts. An overview of current water treatment is presented here where Technology, its limitations and the future, may include Plasmabased advanced oxidation method. In plasma Introduction to liquid water produces and attacks a host of reactive species finally mineralize the contaminants in the solution. This interaction takes place at the boundary layer or at the interaction zone is concentrated at the plasma - liquid water interface. There are limitations of traditional plasma injection procedures which include limited throughput capacity, electrode shear and reduced Process Volume. Here the technical limitations of plasma based water reactor will also be discussed.

scholarly journals Spatial and Temporal Evolution of Ecological Vulnerability Based on Vulnerability Scoring Diagram Model in Shennongjia, China

2021 ◽  
Author(s):  
Jia-shuo Cao ◽  
Yu-qi Yang ◽  
Zheng-yu Deng ◽  
Yuan-dong Hu
Keyword(s):  
Rapid Development ◽  
Composite Index ◽  
Assessment Method ◽  
Landscape Patterns ◽  
Ecological Environment ◽  
Vegetation Coverage ◽  
Ecological Security ◽  
Entire Region ◽  
Aggregation Index ◽  
Ecological Vulnerability

Abstract Background Shennongjia is one of the most important ecological function areas and ecologically vulnerable zones in the world. With the rapid development of social economies, especially tourism, the ecological environment of Shennongjia has experienced profound changes. To describe an assessment method of ecological vulnerability, explain its application in Shennongjia, and propose optimization strategies to reduce the risk of ecosystem vulnerability and maintain regional ecological security and stability. Results (1) During the study period, the overall ecological vulnerability of Shennongjia is in a mild vulnerability level, exhibiting differentiation characteristics of high in the northeast and low in the southwest. High vulnerability zones are mainly distributed in the main towns and roads of Shennongjia. (2) The risk of ecological vulnerability of the entire region presents the characteristics of continuous decline. The ecological vulnerability composite index reaches the lowest value of 2.51 in 2018. (3) Land-use types, population density, and vegetation coverage are the main factors driving the evolution of ecological vulnerability. (4) A high level of coupling coordination exists between ecological vulnerability and landscape patterns, and the contribution of patch number and aggregation index to ecological vulnerability is substantial. Conclusions Analyses of the ecological vulnerability of Shennongjia shows that the entire region is in a mild vulnerability level. The extreme vulnerability risk of the northeast, south and southwest areas appears gradually, the vulnerability degree of the ecological environment shows polarization. The evolution of ecological environment in Shennongjia is the result of the interaction between human activities and natural environment. This study offers an effective way to assess ecological vulnerability and provides some strategies and guidance for improving ecological security.

Sodium persulfate based PVDF membrane for concurrent advanced oxidation and ultrafiltration of ofloxacin in water

2017 ◽  
Vol 315 ◽  
pp. 509-515 ◽  
Author(s):  
Guowen Wang ◽  
Dong Wang ◽  
Xiaoli Dong ◽  
Xiufang Zhang ◽  
Hongchao Ma
Keyword(s):  
Advanced Oxidation ◽  
Sodium Persulfate ◽  
Pvdf Membrane

UV Based Advanced Oxidation Process for Degradation of Ciprofloxacin: Reaction Kinetics, Effects of Interfering Substances and Degradation Product Identification

2021 ◽  
Author(s):  
Bijoli Mondal ◽  
Shib Sankar Basak ◽  
Arnab Das ◽  
Sananda Sarkar ◽  
Asok Adak
Keyword(s):  
Organic Compounds ◽  
Advanced Oxidation Process ◽  
Oxidation Process ◽  
Uv Light ◽  
Degradation Products ◽  
Irradiation Time ◽  
Advanced Oxidation ◽  
Quantum Yields ◽  
Photon Flux ◽  
First Order

Abstract In the photochemical UV-H2O2 advanced oxidation process, H2O2 absorbs UV light and is decomposed to form hydroxyl radicals (OH·), which are highly excited and reactive for electron-rich organic compounds and hence can degrade organic compounds. In the present work, the UV-H2O2 process was investigated to degrade ciprofloxacin (CIP), one of India's widely used antibiotics, from aqueous solutions using a batch type UV reactor having photon flux = 1.9 (± 0.1) ×10-4 Einstein L-1 min-1. The effects of UV irradiation time on CIP degradation were investigated for both UV and UV-H2O2 processes. It was found that about 75% degradation of CIP was achieved within 60 s with initial CIP concentration and peroxide concentration of 10 mg L-1 and 1 mol H2O2/ mol CIP, respectively, at pH of 7(±0.1) and fluence dose of 113 mJ cm-2. The experimental data were analyzed by the first-order kinetics model to find out the time- and fluence-based degradation rate constants. Under optimized experimental conditions (initial CIP concentration, pH and H2O2 dose of 10 mg L-1, 7(±0.1) and 1.0 mol H2O2 / mol CIP, respectively), the fluence-based pseudo-first-order rate constant for the UV and UV-H2O2 processes were determined to be 1.28(±0.0) ×10-4 and 1.20(±0.04) ×10-2 cm2 mJ-1 respectively. The quantum yields at various pH under direct UV were calculated. The impacts of different process parameters such as H2O2 concentration, solution pH, initial CIP concentration, and wastewater matrix on CIP degradation were also investigated in detail. CIP degradation was favorable in acidic conditions. Six degradation products of CIP were identified. Results clearly showed the potentiality of the UV-H2O2 process for the degradation of antibiotics in wastewater.

scholarly journals Direct Catalytic Conversion of CO2 to Cyclic Organic Carbonates under Mild Reaction Conditions by Metal—Organic Frameworks

Catalysts ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 34 ◽  
Author(s):  
Seong Huh
Keyword(s):  
Metal Organic Framework ◽  
Cycloaddition Reaction ◽  
Co2 Concentration ◽  
Reaction Conditions ◽  
Catalytic Systems ◽  
Heterogeneous Catalytic ◽  
Electrochemical Conversion ◽  
Modern Chemical ◽  
Metal Organic ◽  
Carbon Dioxide Co2

The reduction of the representative greenhouse gas, carbon dioxide (CO2), is significantly an important theme for the current research in the modern chemical world. For the last two decades, the development of new metal-organic framework (MOF) systems with highly selective capture of CO2, in the presence of other competing gaseous molecules, has flourished to capture or separate CO2 for environmental protection. Nonetheless, the ultimate resolution to lessen the atmospheric CO2 concentration may be in the chemical or electrochemical conversion of CO2 to other compounds. In this context, the catalytic cycloaddition reaction of CO2 into organic epoxides to produce cyclic carbonates is a more attractive method. MOFs are being proven as efficient heterogeneous catalytic systems for this important reaction. In this review, we collected very recent progress in MOF-based catalytic systems, fully operable under very mild reaction conditions (room temperature and 1 atm CO2).

The Coupling Development between Tourism Economy and Ecological Environment in Harbin City

2013 ◽  
Vol 726-731 ◽  
pp. 4150-4153 ◽  
Author(s):  
Fu Hua Xuan
Keyword(s):  
Rapid Development ◽  
Mathematic Model ◽  
Economic Benefits ◽  
Ecological Environment ◽  
Positive Interaction ◽  
Harmonious Development ◽  
The Sustainable Development ◽  
Negative Effect ◽  
Harbin City ◽  
Tourism Economy

The rapid development of tourism has brought us great economic benefits. However, more and more negative effect on ecology has begun to emerge with large resources and energy consumption. At present, how to improve harmonious development of tourism economy and ecological environment has been a study focus. The mathematic model of the relationship between tourism economy and ecological environment was constructed in this paper, in order to achieve an empirical analysis on the harmonious development of tourism economy and the ecological environment in Harbin City from 2000 and 2010. The results shows that the alternative augmentation of tourism economy and the ecological environment has improved from being slight disorder to being primary coordinated. The tourism economy and the ecological environment share a positive interaction and harmonious development with a coupling coordination. Nevertheless, the level of coupling degree and coordination is still too low. And some countermeasures should be taken to promote the sustainable development of tourism.

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