scholarly journals PHOTOCATALYTIC SOLAR OXIDATION OF ACESULFAME-K. EFFECT OF INITIAL pH, CATALYST DOSE AND OXIDANT CONCENTRATION

2020 ◽  
Author(s):  
Julio César Morales Mejía ◽  
Karla Ibette Anselmo Cervantes ◽  
Iván García Mendoza ◽  
Rafael Almanza
Keyword(s):  
Concentration Ratio ◽  
Photocatalytic Oxidation ◽  
Research Work ◽  
Reaction Conditions ◽  
Photocatalytic Reactor ◽  
Initial Concentration ◽  
Oxidant Concentration ◽  
Initial Ph ◽  
Parabolic Collector ◽  
The Impact

Aqueous acesulfame-K was oxidized in a pilot solar photocatalytic reactor, equipped with a compound parabolic collector (CPC). The reactor has an area of 0.40 m2 of CPC collectors with geometrical concentration ratio of 1 and a simple mechanical configuration. The experiments of photocatalytic oxidation of acesulfame-K were performed by treating 2 L of water with an initial concentration of 15 mg/L. The photocatalyst used was P25 (Aeroxide TiO2) from Evonik. One of the goals of the research work was to find a set of conditions to efficiently remove this emerging concern pollutant. Results allowed proposing a set of reaction conditions that lead to a high removal of acesulfame-K. In addition, the experimental design allowed determining the effect of initial pH as well as the impact of initial concentrations of photocatalyst and chemical oxidant. The removal efficiency of acesulfame-K and related UV-absorbing species reached values up to 96-99 % and there was not a quantifiable amount of intermediate products (analyzed as UV absorbing species). Despite reaction time was fixed in 3 h for all the experiments, oxidation efficiencies higher than 95 % were reached at 2 h of reaction or even before.

scholarly journals PHOTOCATALYTIC SOLAR OXIDATION OF ACESULFAME-K. EFFECT OF INITIAL pH, CATALYST DOSE AND OXIDANT CONCENTRATION

2021 ◽  
Vol 37 ◽  
Author(s):  
Julio César Morales Mejía
Keyword(s):  
Concentration Ratio ◽  
Photocatalytic Oxidation ◽  
Research Work ◽  
Reaction Conditions ◽  
Photocatalytic Reactor ◽  
Initial Concentration ◽  
Oxidant Concentration ◽  
Initial Ph ◽  
Parabolic Collector ◽  
The Impact

Aqueous acesulfame-K was oxidized in a pilot solar photocatalytic reactor, equipped with a compound parabolic collector (CPC). The reactor has an area of 0.40 m2 of CPC collectors with geometrical concentration ratio of 1 and a simple mechanical configuration. The experiments of photocatalytic oxidation of acesulfame-K were performed by treating 2 L of water with an initial concentration of 15 mg/L. The photocatalyst used was P25 (Aeroxide TiO2) from Evonik. One of the goals of the research work was to find a set of conditions to efficiently remove this emerging concern pollutant. Results allowed proposing a set of reaction conditions that lead to a high removal of acesulfame-K. In addition, the experimental design allowed determining the effect of initial pH as well as the impact of initial concentrations of photocatalyst and chemical oxidant. The removal efficiency of acesulfame-K and related UV-absorbing species reached values up to 96-99 % and there was not a quantifiable amount of intermediate products (analyzed as UV absorbing species). Despite reaction time was fixed in 3 h for all the experiments, oxidation efficiencies higher than 95 % were reached at 2 h of reaction or even before.

Photocatalytic degradation of explosives contaminated water

2002 ◽  
Vol 46 (11-12) ◽  
pp. 139-145 ◽  
Author(s):  
S.-J. Lee ◽  
H.-S. Son ◽  
H.-K. Lee ◽  
K.-D. Zoh
Keyword(s):  
Photocatalytic Degradation ◽  
Total Nitrogen ◽  
Contaminated Water ◽  
Ammonium Ions ◽  
Nitrate Ion ◽  
Photocatalytic Reactor ◽  
Initial Concentration ◽  
Initial Ph ◽  
Alkaline Conditions ◽  
The Impact

This study was undertaken to examine the degradation of TNT, RDX and HMX in a circular photocatalytic reactor with TiO2 as a photocatalyst. We examined the impact of parameters such as the initial concentration, initial pH of solution on rates of photocatalized transformation, and the mineralization. The results showed that photocatalysis is an effective process for the degradation of TNT, RDX and HMX. They could be completely degraded in 150 min with 1.0 g/L TiO2 at pH 7. An increase in the photocatalytic degradation of HMX was noticed with decreasing initial HMX. The rates of RDX and HMX degradation were greater in neutral pH than in acidic and alkaline conditions. In case of TNT degradation, the rate of degradation was the fastest at pH 11. Approximately 82% TOC decrease in the TNT degradation was achieved after 150 min, whereas TOC decrease in RDX and HMX was 24% and 59%, respectively. Nitrate, nitrite, and ammonium ions were detected as the nitrogen byproducts from the photocatalysis, and more than 50% of the total nitrogen was recovered as nitrate ion in every explosives.

scholarly journals Influence of Operating Parameters on Photocatalytic Oxidation of 2,4-Dichlorofenol in Aqueous Solution by TiO2/Stainless Steel Photocatalytic Membrane

2021 ◽  
Vol 11 (24) ◽  
pp. 11664
Author(s):  
Liliana Bobirică ◽  
Constantin Bobirică ◽  
Giovanina Iuliana Lupu ◽  
Cristina Orbeci
Keyword(s):  
Stainless Steel ◽  
Photocatalytic Degradation ◽  
Photocatalytic Oxidation ◽  
Oxidation Process ◽  
Organic Substrate ◽  
Molar Ratio ◽  
Operating Parameters ◽  
Photocatalytic Reactor ◽  
Initial Concentration ◽  
Working Solution

The influence of some operating parameters of an UV photocatalytic reactor with TiO2/stainless steel photocatalytic membrane on the photocatalytic oxidation of 2,4-dichlorophenol from aqueous solutions was studied in this paper. It was shown that the pH of the working solution substantially influences the photocatalytic degradation of the organic substrate, with the degradation efficiency increasing with decreasing the pH of the working solution by a maximum corresponding to pH 3. The rate constant of the photocatalytic oxidation process is about twice as high at pH 3 comparative with pH 7 for the same initial concentration of the organic substrate. The molar ratio of hydrogen peroxide/organic substrate also influences the photocatalytic oxidation process of the organic substrate. The results obtained in this paper highlight the fact that a stoichiometric molar ratio is favorable for the photocatalytic degradation of 2,4-dichlorophenol. It has also been shown that the initial concentration of the organic substrate influences the rate of photocatalytic degradation. It appears that the rate of photocatalytic degradation decreases with the increasing of initial concentration of 2,4-dichlorophenol.

Degradation of Ammonium butyl-dithiophosphate by Fe2+/NaClO Process

2013 ◽  
Vol 800 ◽  
pp. 601-605
Author(s):  
Xi Sheng He ◽  
Hui Qing Peng
Keyword(s):  
Aqueous Solution ◽  
Exponential Decay ◽  
Reaction Conditions ◽  
Initial Concentration ◽  
First Order ◽  
Initial Ph ◽  
Optimum Reaction

The initial pH, initial concentration of Fe2+and NaClO on the degradation of ammonium butyl-dithiophosphate using Fe2+/NaClO process have been investigated in this paper. The results shows that under the optimum reaction conditions of a temperature 28°C, pH 4.0, the initial concentration of Fe2+and NaClO is 15 mg/L and 5.33 mL/L, respectively, about 87.86% ammonium butyl-dithiophosphate removal can be achieved within 150 min by using a Fe2+/NaClO process. The degradation of ammonium butyl-dithiophosphate under different NaClO concentration conditions follows the first order exponential decay equations. The Fe2+/NaClO can efficiently oxidation of ammonium butyl-dithiophosphate in aqueous solution and can be an effective process for the treatment of ammonium butyl-dithiophosphate wastewater.

scholarly journals Characteristics of Carbon Monoxide Oxidization in Rich Hydrogen by Mesoporous Silica with TiO2Photocatalyst

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Akira Nishimura ◽  
Yutaka Yamano ◽  
Tomokazu Hisada ◽  
Masafumi Hirota ◽  
Eric Hu
Keyword(s):  
Carbon Monoxide ◽  
Mesoporous Silica ◽  
Concentration Ratio ◽  
Uv Light ◽  
Polymer Electrolyte Fuel Cell ◽  
Light Illumination ◽  
Experimental Conditions ◽  
Initial Concentration ◽  
Loading Ratio ◽  
The Impact

Hydrogen (H2) is normally used as the fuel to power polymer electrolyte fuel cell (PEFC). However, the power generation performance of PEFC is harmed by the carbon monoxide (CO) in the H2that is often produced frommethane (CH4). The purpose of this study is to investigate the experimental conditions in order to improve the CO oxidization performance of mesoporous silica loaded with TiO2. The impact of loading ratio of TiO2and initial concentration ratio of O2to CO on CO oxidization performance is investigated. As a result, the optimum loading ratio of TiO2and initial concentration ratio of O2to CO were 20 wt% and 4 vol%, respectively, under the experimental conditions. Under this optimumexperimental condition, the CO in rich H2in the reactor can be completely eliminated from initial 12000 ppmV after UV light illumination of 72 hours.

scholarly journals A Study on Oxidation of Tetramethylammonium Hydroxide (TMAH) using UV/Persulfate

2020 ◽  
Vol 42 (10) ◽  
pp. 443-451
Author(s):  
Hyo-yeon Choi ◽  
Daewon Pak
Keyword(s):  
Removal Efficiency ◽  
Reaction Rate Constant ◽  
Treatment Efficiency ◽  
High Concentration ◽  
Reaction Conditions ◽  
Factors Affecting ◽  
Oxidant Concentration ◽  
Degradation Rates ◽  
Initial Ph ◽  
Optimum Reaction

Objective : In order to efficiently remove TMAH from the wastewater generated by the TFT-LCD manufacturing process, the oxidation of TMAH was tested by applying an UV/persulfate. The optimum reaction conditions for high concentration TMAH oxidation were investigated by evaluating and comparing the removal efficiency according to the factors affecting TMAH oxidative degradation.Methods : In this study, TMAH was decomposed by sulfate radical (SO4-∙) and hydroxyl radical (OH∙) generated from persulfate activated by UV. Factors affecting on the treatment efficiency were try to be optimized by comparing and evaluating the removal efficiency depending on the initial pH, oxidant concentration, and initial TMAH concentration.Results and Discussion : Depending on initial pH (2, 7, 12), persulfate addition (0, 50, 100, 150, 200 mM), initial TMAH concentration (100, 300, 500, 700 mg/L) degradation rates of TMAH were compared. When UV/persulfate was applied, the removal efficiency of TMAH was close to 90% regardless of the initial pH and, at initial pH 12, was the highest with 89%. It was confirmed that the generation pattern of intermediate formed were different depending on the initial pH. When the oxidizing agent was not added, there was little change in TMAH concentration. The removal efficiency was highest when 100 mM persulfate was added. However the efficiency was rather low when 150 mM persulfate was added. When the initial TMAH concentration was 100 mg/L, it was decreased within 150 minutes. As the initial concentration increased, the removal efficiency and reaction rate constant decreased.Conclusions : As a results, during the oxidation of 750 mg/L TMAH by using UV/persulfate, the removal efficiency was highest with initial pH 12 and 100 mM of persulfate addition.

Piezoelectric β-polymorph formation of new textiles by surface modification with coating process based on interfacial interaction on the conformational variation of poly (vinylidene fluoride) (PVDF) chains

2020 ◽  
Vol 91 (3) ◽  
pp. 31301
Author(s):  
Nabil Chakhchaoui ◽  
Rida Farhan ◽  
Meriem Boutaldat ◽  
Marwane Rouway ◽  
Adil Eddiai ◽  
...  
Keyword(s):  
High Efficiency ◽  
Vinylidene Fluoride ◽  
Research Work ◽  
Research Area ◽  
Interfacial Interaction ◽  
Tetraethyl Orthosilicate ◽  
Poly Vinylidene Fluoride ◽  
Carbon Nanofillers ◽  
The Impact ◽  
Advanced Applications

Novel textiles have received a lot of attention from researchers in the last decade due to some of their unique features. The introduction of intelligent materials into textile structures offers an opportunity to develop multifunctional textiles, such as sensing, reacting, conducting electricity and performing energy conversion operations. In this research work nanocomposite-based highly piezoelectric and electroactive β-phase new textile has been developed using the pad-dry-cure method. The deposition of poly (vinylidene fluoride) (PVDF) − carbon nanofillers (CNF) − tetraethyl orthosilicate (TEOS), Si(OCH2CH3)4 was acquired on a treated textile substrate using coating technique followed by evaporation to transform the passive (non-functional) textile into a dynamic textile with an enhanced piezoelectric β-phase. The aim of the study is the investigation of the impact the coating of textile via piezoelectric nanocomposites based PVDF-CNF (by optimizing piezoelectric crystalline phase). The chemical composition of CT/PVDF-CNC-TEOS textile was detected by qualitative elemental analysis (SEM/EDX). The added of 0.5% of CNF during the process provides material textiles with a piezoelectric β-phase of up to 50% has been measured by FTIR experiments. These results indicated that CNF has high efficiency in transforming the phase α introduced in the unloaded PVDF, to the β-phase in the case of nanocomposites. Consequently, this fabricated new textile exhibits glorious piezoelectric β-phase even with relatively low coating content of PVDF-CNF-TEOS. The study demonstrates that the pad-dry-cure method can potentially be used for the development of piezoelectric nanocomposite-coated wearable new textiles for sensors and energy harvesting applications. We believe that our study may inspire the research area for future advanced applications.

Microstructural and Mechanical Behaviour Evaluation of Mg-Al-Zn Alloy Friction Stir Welded Joint

2020 ◽  
Vol 17 (3) ◽  
pp. 8150-8159
Author(s):  
Kulwant Singh ◽  
Gurbhinder Singh ◽  
Harmeet Singh
Keyword(s):  
Heat Treatment ◽  
Friction Stir Welding ◽  
Magnesium Alloys ◽  
Mechanical Performance ◽  
Fuel Efficiency ◽  
Research Work ◽  
Grain Structure ◽  
Tensile Fracture ◽  
Friction Stir ◽  
The Impact

The weight reduction concept is most effective to reduce the emissions of greenhouse gases from vehicles, which also improves fuel efficiency. Amongst lightweight materials, magnesium alloys are attractive to the automotive sector as a structural material. Welding feasibility of magnesium alloys acts as an influential role in its usage for lightweight prospects. Friction stir welding (FSW) is an appropriate technique as compared to other welding techniques to join magnesium alloys. Field of friction stir welding is emerging in the current scenario. The friction stir welding technique has been selected to weld AZ91 magnesium alloys in the current research work. The microstructure and mechanical characteristics of the produced FSW butt joints have been investigated. Further, the influence of post welding heat treatment (at 260 °C for 1 h) on these properties has also been examined. Post welding heat treatment (PWHT) resulted in the improvement of the grain structure of weld zones which affected the mechanical performance of the joints. After heat treatment, the tensile strength and elongation of the joint increased by 12.6 % and 31.9 % respectively. It is proven that after PWHT, the microhardness of the stir zone reduced and a comparatively smoothened microhardness profile of the FSW joint obtained. No considerable variation in the location of the tensile fracture was witnessed after PWHT. The results show that the impact toughness of the weld joints further decreases after post welding heat treatment.

Serving the People in Long Beach, California: Advancing Justice for Southeast Asian Youth through Community University Research Partnerships

2019 ◽  
Vol 16 (1-2) ◽  
pp. 1-34
Author(s):  
R. Varisa Patraporn
Keyword(s):  
Asian American ◽  
Research Work ◽  
Community Based Participatory Research ◽  
Youth Empowerment ◽  
Long Beach ◽  
Structured Interviews ◽  
Research Partnerships ◽  
Community Needs ◽  
The People ◽  
The Impact

Khmer Girl’s in Action is a nonprofit that successfully utilizes community-based participatory research (CBPR) with university partners to create social change for youth in Long Beach, CA. Based on semi-structured interviews and content analysis of news articles, I explore the impact and sustainability of this research work and the research partnerships. Findings highlight impacts such as youth empowerment, heightened awareness around community needs, policy change, and CBPR curriculum improvements in the field as impacts. Sustainability requires integrating research into program funding, utilizing a tailored training curriculum, building on community members prior relationships, and selecting partners that share common goals, levels of commitment, and flexibility. As funders demand more data to justify community needs, understanding more examples of such work in the Asian American community will be useful for informing future partnerships.

Impacto de las tecnologías de la información y las comunicaciones: Una mirada en la Educación Superior

2017 ◽  
Vol 1 (6) ◽  
Author(s):  
Karina Virginia Mero Suárez ◽  
Edwin Joao Merchán Carreño ◽  
Ana Del Rocío Fernández Torres ◽  
Narcisa María Crespo Torres
Keyword(s):  
Higher Education ◽  
Information Technology ◽  
Research Work ◽  
Field Research ◽  
Research Problem ◽  
Research Report ◽  
Educación Superior ◽  
Educational Design ◽  
Educacion Superior ◽  
The Impact

El artículo aborda la necesidad de la creatividad que se impone en la era actual del conocimiento y la importancia que  constituyen las tecnologías como herramientas indispensables en todas las esferas de la vida. En Trabajo toma como campo investigativo los cambios que se llevan a cabo en esta esfera en la Universidad Estatal del Sur de Manabí y la Universidad Técnica de Babahoyo, Ecuador, donde se toman como objeto el proceso de enseñanza aprendizaje en la Educación Superior. El objetivo de la investigación fue comunicar el impacto de las Tecnologías de la Información y las Comunicaciones en las Universidades, donde se hace énfasis en el nuevo rol de los docentes y su nuevo desempeño de facilitadores del aprendizaje en los educandos a través en los nuevos escenarios mediados por las tecnologías. Para el desarrollo exitoso de esta memoria investigativa se   usó como metodología instrumentos que se basaron fundamentalmente en documentos referativos que ayudaron a justificar el problema de investigación, el cual consistía fundamentalmente en el impacto de las nuevos  dispositivos tecnológicos y su utilidad en los centros de altos estudios del país. Se concluyó que las Tecnologías de la Información y Comunicación son herramientas indispensables en la docencia y al mismo tiempo la forma de intervenir en el diseño educativo que nos llevan a explorar nuevos métodos docentes en los escenarios educativos mediados por estas. Se constató además que estas herramientas favorecen satisfactoriamente al proceso si se tiene una buena preparación por parte del docente.   Palabras clave: Herramientas tecnológicas, universidades, formación, docencia universitaria, proceso de enseñanza – aprendizaje Impact of information technology and communications: a look at higher education  Abstract The article states the need of the creativity that prevails in the current era of knowledge and the importance that technologies constitute in all spheres of life. In field research work it takes as changes take place in this area in Southern State University of Manabí and the Technical University of Babahoyo, Ecuador, where they are taken as an object the process of learning in higher education. The aim of the research was to communicate the impact of Information Technology and Communications in the universities, where the emphasis is on the new role of teachers and their new performance of facilitators of learning in students through the new scenarios mediated by technologies. For the successful development of this research report it was used as a methodology instruments based mainly on referative documents that helped to justify the research problem, which consisted mainly of the impact of new technological devices and their use in the centers of higher learning in the country. It was concluded that information technology and communication are indispensable tools in teaching and at the same time how to intervene in the educational design that lead us to explore new teaching methods in educational settings mediated by these. It was further found that these tools successfully promote the process if there is a good preparation by the teacher.

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