To see the other types of publications on this topic, follow the link: Oxidation-reduction reaction – Study and teaching.
Journal articles on the topic 'Oxidation-reduction reaction – Study and teaching'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Oxidation-reduction reaction – Study and teaching.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Rahmawati, Sitti, and Bunbun Bundjali. "KINETICS OF THE OXIDATION OF VITAMIN C." Indonesian Journal of Chemistry 12, no. 3 (2012): 291–96. http://dx.doi.org/10.22146/ijc.21345.
Full textAbstract:
Vitamin C or ascorbic acid is needed by the human body but it is already damaged by the rise in temperature due to be oxidized to L-dehydroascorbic acid. This research aims to determine the kinetics of oxidation of ascorbic acid due to an increase if temperature (40-80 °C) and to design an ascorbic acid oxidation reaction laboratory module to be applied in the senior high school reaction kinetics curriculum. The determination of the kinetics of the oxidation of ascorbic acid applies the integral and half-change time methods, while the concentration of the remained ascorbic acid in sixty minute intervals is determined by iodimetric titration method. Decomposition of ascorbic acid was measured at 40, 50, 60, 70 and 80 °C. The results of this research indicate that at 40, 50, 60, 70 and 80 °C the kinetics of the oxidation of ascorbic acid is a first-order reaction with rate constants of 4.55 x 10-4, 5.85 x 10-4, 8.4 x 10-4, 1.1 x 10-3 and 1.015 x 10-3 min-1, respectively. Pre-exponential factor or the frequency of collisions is a factor which is a measure of the collision rate. The activation energy and the pre-exponential factor for the oxidation of ascorbic acid were found to be 20.73 kJ.mol-1 and 1.372 min-1. The procedure used in this study was modified into a laboratory module will be applied in the teaching of reaction kinetics at the senior high school level.
2
Shikdar, Sufana, Kavita Agrawal, Nicholas Ghionni, et al. "The Appropriateness of Fresh Frozen Plasma (FFP) Administration in Three Community Teaching Hospitals." Blood 134, Supplement_1 (2019): 5789. http://dx.doi.org/10.1182/blood-2019-127693.
Full textAbstract:
Objective: Although Fresh Frozen Plasma (FFP) is indicated in critically ill patients, there are growing concerns about it's cost effectiveness and adverse effects in instances that do not conform to evidence-based indications. Despite a range of adverse reaction with the inappropriate usage of FFP, its usage has significantly increased over the last decade. We previously evaluated the overuse of FFP in our community teaching hospital in 2010-2011 and 2016-2017. The interventions to reduce the inappropriate FFP transfusion were implemented after the results from 2016-2017. The present multicenter study is a post-interventional study that describes practices regarding administration of FFP in three community teaching hospitals between 2017-2018. Methods: A retrospective chart review of patients who received FFP transfusion in three community teaching hospitals between 2017-2018 were included in our study. Criteria were established to evaluate the appropriateness of FFP. Descriptive statistics were utilized to compare the appropriateness of FFP transfusion among the participating hospitals. Results: Overall, 306 participants were evaluated where 25% of the participants (77 out of 306) received inappropriate FFP transfusions. The most common rationale for inappropriate FFP transfusions were bleeding with INR less than 1.5 followed by INR over 1.5 (without any evidence of active bleeding).Based on our study criteria, the proportion of inappropriate FFP transfused out of the total FFP transfused decreased from 49% in the study period 2016-2017 to 25% in the study period 2017-2018. 15% of the study population received inappropriate FFP transfusion for bleeding in 2017-2018 compared to 42% in 2016-2017. Conclusion: Our study showed a reduction in inappropriate FFP transfusions in 2017-2018 compared to 2016-2017. This can be attributed to the interventions implemented after obtaining study results from 2016-2017. The interventions included creating fliers educating about lack of effectiveness of FFP to reduce INR below 1.6 and arranging educational talks from transfusion committee about the evidence-based usage of FFP transfusion. Such interventions are essential to reduce healthcare expenditure and transfusion related adverse events. Disclosures No relevant conflicts of interest to declare.
3
Suherman, Wawan Sundawan, Dapan Dapan, Guntur Guntur, and Nur Rohmah Muktiani. "DEVELOPMENT OF A TRADITIONAL CHILDREN GAME BASED INSTRUCTIONAL MODEL TO OPTIMIZE KINDERGARTENERS’ FUNDAMENTAL MOTOR SKILL." Jurnal Cakrawala Pendidikan 38, no. 2 (2019): 356–65. http://dx.doi.org/10.21831/cp.v38i2.25289.
Full textAbstract:
Traditional children game is proposed as a suitable physical activity for instructional mean in kindergarten. The research intends to develop traditional children game based instructional model to optimize development of fundamental motor skills of kindergarteners. This research and development used an approach from Borg & Gall. The research involved kindergartens in Yogyakarta, Indonesia. Data were collected by interview, observation, and documentation, and then were analyzed in three steps: organization and reduction, displaying, and summarization and verification. The study phase follows activities: identification of theoretical basis and determination of instructional model design, identification and analysis of traditional children game, and validation of instructional model. After being validated by material experts and teaching experts, the traditional children game based instructional model for optimizing the development of kindergarteners’ fundamental motor skills consists of: (1) concepts/theoretical basis, (2) activity stages, (3) social systems, (4) principles of reaction, (5) supporting system, and (6) model impact.
4
Semeniv, Bogdan, Taras Prystavskyi, М. М. Стахів, Olena Gоlubeva, and Julia Sopila. "Influence of varieties of aerobics on the psychophysiological condition of women of the teaching staff." Scientific Journal of National Pedagogical Dragomanov University. Series 15. Scientific and pedagogical problems of physical culture (physical culture and sports), no. 3(123) (July 28, 2020): 131–37. http://dx.doi.org/10.31392/npu-nc.series15.2020.3(123).25.
Full textAbstract:
Ukraine carries out a wide range of measures that create the necessary conditions for work and life, improvement of the external, including industrial, environment, further development of health care. At the same time, human activity by means of physical culture and sports are important factors in improving and strengthening health, which ultimately increases a person's creative activity, his ability to work. Aim of the research - to determine experimentally the effectiveness of the application of aerobics on the psychophysiological state and the special ability of women of the teaching staff. The following research methods were used to achieve the goal: analysis, generalization, systematization of literature sources on the problem of research, questionnaires, surveys, psychophysiological research methods, pedagogical research methods. Results of the research: exercise in classical aerobics contributes to the activation of various structures of the CNS, as a result of which women began to respond more quickly to light signals. Special working capacity increased by 48.5%. Having completed the study of strength aerobics classes in women, there was a significant increase in the potential of cardiohemodynamics. Training complexes of physical exercises in aerobics with the use of various equipment, lead to the activation of different parts of the cerebral cortex, which is expressed in a reduction (approximately 15%) of the visual-motor reaction time, increases (approximately 14.5%) special performance. Under the influence of training on strength training equipment in women, the potential of cardiohemodynamics decreases, and on the other hand, as a result of activation of the cortical structures of the brain, professional efficiency increases. Conclusions. Systematic physical culture and sports normalize the work of almost all organs and systems of the body, increase the psycho-emotional state, physical and mental activity.
5
Thandu, Sanjeeva Kumar Goud, A. N. Vijay Kumar, and Rahul Rajendra Kunkulol. "Pharmacoeconomics of allergic rhinitis drugs treatment in tertiary care hospital." International Journal of Basic & Clinical Pharmacology 8, no. 10 (2019): 2313. http://dx.doi.org/10.18203/2319-2003.ijbcp20194278.
Full textAbstract:
Background: Allergic rhinitis also called hay fever; it is a very common in India. Harmless exposing substances cause an allergic reaction. Allergic rhinitis is of the two types, one is the seasonal occurred with the change of seasons, second is the perennial means any time during the year.Methods: This was a cross-sectional study to determine the cost analysis allergic rhinitis drugs used in treatment of ENT OPD in a tertiary care teaching hospital, Kamothe, Navi Mumbai. The patients were interviewed; prescriptions were analyzed number of medicines prescribed.Results: Incidence of polypharmacy two drugs per prescriptions were prescribed 140 and three drugs per prescriptions 60. In the total number of 200 prescriptions, the cost of 43 prescriptions were in between 251-300 Indian rupees and 18 prescriptions were 301-350 Indian rupees. Patient knowledge about the drug use in this study, out of 200 pts 37% of allergic rhinitis patients knew the correct dosage of the prescribed drugs while 63% were not aware.Conclusions: Majority of the participants drugs were prescribed two to three drugs, per prescription cost was high because all the drugs prescribed by brand name and no drugs were prescribed by generic name. Improvement in knowledge about generic medicines is important factor to prefer generic medicine. Reduction in cost of drug will improve compliance.
6
Rateb, Mahmoud F., Hazem Abdel Motaal, Mohamed Shehata, Mohamed Anwar, Dalia Tohamy, and Mohamed G. A. Saleh. "Outcome of a Low-Cost Glaucoma Implant versus the Baerveldt Glaucoma Implant for Paediatric Glaucoma in a Tertiary Hospital in Egypt." Journal of Ophthalmology 2019 (December 20, 2019): 1–6. http://dx.doi.org/10.1155/2019/5134190.
Full textAbstract:
Purpose. To compare safety and efficacy between a low-cost glaucoma drainage device (GDD), the Aurolab aqueous drainage implant (AADI), and the Baerveldt glaucoma implant (BGI) in refractory childhood glaucoma in Egypt. Methods. This is a retrospective study of patients who received either an AADI or BGI at a tertiary care postgraduate teaching institute. Children aged <16 years with uncontrolled intraocular pressure (IOP) with or without prior failed trabeculectomy who completed a minimum 6-month follow-up were included. The outcome measures were IOP reduction from preoperative values and postoperative complications. Results. Charts of 57 children (younger than 16 years old) diagnosed with refractory childhood glaucoma were included. Of these, 27 eyes received AADI implants (group A), while 30 received BGI implants (group B). The mean preoperative baseline IOP was 34 ± 5 mmHg in group A versus 29 ± 2 mmHg in group B (p=0.78) in patients on maximum allowed glaucoma medications. In group A versus group B, the mean IOP decreased to 13.25 ± 8.74 mmHg (p=0.6), 12.8 ± 5.4 mmHg (p=0.7), and 12.6 ± 5.6 mmHg (p=0.9) after 1 week, 3 months, and 6 months, respectively. However, in group A, an anterior chamber reaction appeared around the tube in 14 cases starting from the first month and resolved with treatment in only 4 cases. In the other 10 cases, the reaction became more severe and required surgical intervention. This complication was not observed in any eye in group B. Conclusion. AADI, a low-cost glaucoma implant, is effective in lowering IOP in patients with recalcitrant paediatric glaucoma. However, an intense inflammatory reaction with serious consequences developed in some of our patients; we believe these events are related to the valve material. We therefore strongly recommend against its use in children.
7
Park, Keun-Ho, and Ju-Yeong Song. "A Study on the Oxidation-reduction Reaction of Organic Thin Films." Journal of the Korean Institute of Electrical and Electronic Material Engineers 19, no. 8 (2006): 724–31. http://dx.doi.org/10.4313/jkem.2006.19.8.724.
Full text
8
Locatelli, Solange, Paulo Henrique Soares Gomes, and Agnaldo Arroio. "CONNECTIONS INVOLVING THE USE OF CHEMICAL LANGUAGE AND UNDERSTANDING OF REDUCTION-OXIDATION REACTION." GAMTAMOKSLINIS UGDYMAS / NATURAL SCIENCE EDUCATION 15, no. 2 (2018): 61–71. http://dx.doi.org/10.48127/gu-nse/18.15.61.
Full textAbstract:
Understanding submicroscopic level, which requires in-depth chemistry knowledge, is difficult for students. The sample of the research consisted of 32 students, who performed a teaching-learning sequence of two electrochemical reactions. Eight of them were videotaped and their speech was transcribed and analyzed. The results indicated that students who used more chemical terms improved their understanding of the submicroscopic level. Talking more, in this case, showed no relation to learning directed to an instrumental understanding (focus on how). The use of more chemical terms enabled them to grasp a relational understanding (focus on why) and the predictive ability of new chemical phenomena. Keywords: chemical education, chemical terms, electrochemistry, relational understanding, submicroscopic level.
9
Nazirun, Muhammad Mukhlis, and Ermawati S. "Struktur dan Kaidah Teks Anekdot dalam Kumpulan Cerita Abu Nawas." GERAM 8, no. 1 (2020): 60–69. http://dx.doi.org/10.25299/geram.2020.vol8(1).4964.
Full textAbstract:
The background of the research was based on the existence of Abu Nawas stories that contain humor aspects. Besides, it has its uniqueness, so that readers are curious. The story of Abu Nawas is categorized as an anecdotal story because it contains the same structure and rules as the anecdotal text. Besides it also has a moral value so that it can be used as alternative teaching material at schools. Regarding the importance of Abu Nawas story, this study aimed to describe the structure and rules of anecdotal texts in the collection of Abu Nawas stories. This research was descriptive qualitative research. This research was conducted in literature. The research took six months. Data was collected using documentation techniques. This research data contained the text of the Abu Nawas anecdotal story containing structure and language use. The data analysis technique used in this study was the procedure and analysis model according to Miles and Huberman which consists of three stages, namely, data reduction, data presentation, and conclusion or verification. The results of this study, first, in terms of the generic structure, 44 anecdotal texts were perfect and 14 texts were not complete. It was proven by the average value which was 94% and was categorized complete based on the standard of anecdotal text structure covering abstract, orientation, crisis, reaction, and coda. Second, in terms of language use, 19 stories were complete and 39 stories did not use the language use properly. It was proven by the average value which was 75% and was categorized complete. The language features used in the form of past tense, rhetorical questions, temporal conjunction, material verbs, and imperative sentences.
10
Chiang, Wen-Wei, Mei-Hung Chiu, Shiao-Lan Chung, and Chun-Keng Liu. "SURVEY OF HIGH SCHOOL STUDENTS’ UNDERSTANDING OF OXIDATION-REDUCTION REACTION." Journal of Baltic Science Education 13, no. 5 (2014): 596–607. http://dx.doi.org/10.33225/jbse/14.13.596.
Full textAbstract:
This study investigated the conceptions of 340 Taiwanese high school students (grades 10 to 12) regarding oxidation–reduction reactions. The diagnostic tool used was a two-tier test based on a concept map of redox reactions as presented in high school curriculums. The reliability of the two-tier test items was 0.82. The results show that most 11th graders performed equally well in questions related to the concept of the gain and loss of electrons during oxidation–reduction. In terms of working with oxidation numbers, scores increased with grade level. The results of this study provide valuable reference for curriculum designers and science instructors. Key words: concept map, oxidation–reduction, redox, two-tier.
11
Dayo-Olagbende, Gabriel Olufemi, Solomon Alaba Adejoro, Babatunde Sunday Ewulo, and Moses Adeyemi Awodun. "Effects of Oxidation-Reduction Potentials on Soil Microbes." Agricultura 16, no. 1-2 (2019): 35–42. http://dx.doi.org/10.18690/agricultura.16.1-2.35-42.2019.
Full textAbstract:
Soil microbes are important in various processes that lead to soil fertility, nutrient availability and plant nutrition. These soil microbial organisms are themselves affected by the environment where they occur. Microbes could either be aerobic or anaerobic depending on their oxygen requirements. Oxidation-reduction reaction is a common reaction in anoxic environments and microbes tend to respond to it in different ways. This study therefore sets out to investigate the effect of oxidation-reduction potentials of the soil on activities of soil microorganisms. Results from this study show that highly reduced soils favors bacteria population more than fungi. It was concluded that the survival of fungi is best supported under oxidized and moderately reduced soils, but their existence can be negatively affected when soils become highly reduced. Bacteria that are aerobic thrive best under oxidized and moderately reduced soil. In these conditions, the highest microbial respiration in the soil was also measured.
12
Zhou, Shuqin, Shaoyi Li, and Huadong Bai. "Study on Crosslinking in Diimide Reduction of Nitrile Butadiene Rubber." Rubber Chemistry and Technology 79, no. 4 (2006): 602–9. http://dx.doi.org/10.5254/1.3547954.
Full textAbstract:
Abstract Acrylonitrile-butadiene rubber (NBR) in latex form was selectively hydrogenated by redox system consisting of hydrazine hydrate and hydrogen peroxide, with boric acid as catalyst. Soluble hydrogenated NBR latex was obtained; but the coagulated products were gelled on drying. This problem becomes the major obstacle for the hydrogenation technique to be commercialized. It is important to study the crosslinking reaction in the system and to solve the problem. The cause for the crosslink was investigated in three possibilities: (i) crosslinking caused by the hydrogenation of CN group; (ii) by the oxidation of C=C double bonds and (iii) by radicals in the system. The control of the crosslink was also studied. The oil resistant nitrile group —CN on the polymer chain had no change during drying process. There were no signs of carbonyl group C=O formed by oxidation and amine like groups -NH- formed by the hydrogenation of CN in HNBR gel fraction. The newly formed alkoxyl radicals were detected by ESR spectroscopy analysis in the hydrogenation system after specific reaction time. Crosslinking reaction was controlled to a large extent by using hydroquinone as gel inhibitor.
13
Trick, William E., Stephen J. Sokalski, Stuart Johnson, et al. "Effectiveness of Probiotic for Primary Prevention of Clostridium difficile Infection: A Single-Center Before-and-After Quality Improvement Intervention at a Tertiary-Care Medical Center." Infection Control & Hospital Epidemiology 39, no. 07 (2018): 765–70. http://dx.doi.org/10.1017/ice.2018.76.
Full textAbstract:
OBJECTIVETo evaluate probiotics for the primary prevention of Clostridium difficile infection (CDI) among hospital inpatients.DESIGNA before-and-after quality improvement intervention comparing 12-month baseline and intervention periods.SETTINGA 694-bed teaching hospital.INTERVENTIONWe administered a multispecies probiotic comprising L. acidophilus (CL1285), L. casei (LBC80R), and L. rhamnosus (CLR2) to eligible antibiotic recipients within 12 hours of initial antibiotic receipt through 5 days after final dose. We excluded (1) all patients on neonatal, pediatric and oncology wards; (2) all individuals receiving perioperative prophylactic antibiotic recipients; (3) all those restricted from oral intake; and (4) those with pancreatitis, leukopenia, or posttransplant. We defined CDI by symptoms plus C. difficile toxin detection by polymerase chain reaction. Our primary outcome was hospital-onset CDI incidence on eligible hospital units, analyzed using segmented regression.RESULTSThe study included 251 CDI episodes among 360,016 patient days during the baseline and intervention periods, and the incidence rate was 7.0 per 10,000 patient days. The incidence rate was similar during baseline and intervention periods (6.9 vs 7.0 per 10,000 patient days; P=.95). However, compared to the first 6 months of the intervention, we detected a significant decrease in CDI during the final 6 months (incidence rate ratio, 0.6; 95% confidence interval, 0.4–0.9; P=.009). Testing intensity remained stable between the baseline and intervention periods: 19% versus 20% of stools tested were C. difficile positive by PCR, respectively. From medical record reviews, only 26% of eligible patients received a probiotic per the protocol.CONCLUSIONSDespite poor adherence to the protocol, there was a reduction in the incidence of CDI during the intervention, which was delayed ~6 months after introducing probiotic for primary prevention.Infect Control Hosp Epidemiol 2018;765–770
14
Hussein, Aqeel A., Azzam A. M. Al-Hadedi, Alaa J. Mahrath, et al. "Mechanistic investigations on Pinnick oxidation: a density functional theory study." Royal Society Open Science 7, no. 2 (2020): 191568. http://dx.doi.org/10.1098/rsos.191568.
Full textAbstract:
A computational study on Pinnick oxidation of aldehydes into carboxylic acids using density functional theory (DFT) calculations has been evaluated with the (SMD)-M06-2X/aug-pVDZ level of theory, leading to an important understanding of the reaction mechanism that agrees with the experimental observations and explaining the substantial role of acid in driving the reaction. The DFT results elucidated that the first reaction step (FRS) proceeds in a manner where chlorous acid reacts with the aldehyde group through a distorted six-membered ring transition state to give a hydroxyallyl chlorite intermediate that undergoes a pericyclic fragmentation to release the carboxylic acid as a second reaction step (SRS). 1 H NMR experiments and simulations showed that hydrogen bonding between carbonyl and t -butanol is unlikely to occur. Additionally, it was found that the FRS is a rate-determining and thermoneutral step, whereas SRS is highly exergonic with a low energetic barrier due to the Cl(III) → Cl(II) reduction. Frontier molecular orbital analysis, intrinsic reaction coordinate, molecular dynamics and distortion/interaction analysis further supported the proposed mechanism.
15
Qin, Wu, Qiuluan Chen, Yang Wang, et al. "Theoretical study of oxidation–reduction reaction of Fe2O3 supported on MgO during chemical looping combustion." Applied Surface Science 266 (February 2013): 350–54. http://dx.doi.org/10.1016/j.apsusc.2012.12.023.
Full text
16
Brillas, Enrique, José A. Garrido, Joaquin F. Perez-Benito, Rosa M. Rodriguez, and Jaime de Andres. "Kinetic study of permanganate oxidation of L-leucine in neutral aqueous solution." Collection of Czechoslovak Chemical Communications 53, no. 3 (1988): 479–86. http://dx.doi.org/10.1135/cccc19880479.
Full textAbstract:
The permanganate oxidation of L-leucine in aqueous phosphate buffers over the pH range 6.1 – 7.6 is autocatalyzed by the manganese reduction product, a soluble form of colloidal manganese dioxide. The kinetic data for both the non-catalytic and autocatalytic reaction pathways have been obtained, and mechanism in agreement with them proposed. The non-catalytic pathway takes place by reaction between either the anionic or the zwitterionic form of the amino acid and permanganate ion, whereas the autocatalytic pathway is realized by the permanganate oxidation of the amino acid previously adsorbed on the colloid surface.
17
Huang, Tzu-Hsi, Dinesh Bhalothia, Shuan Lin, Yu-Rewi Huang, and Kuan-Wen Wang. "The Ethanol Oxidation Reaction Performance of Carbon-Supported PtRuRh Nanorods." Applied Sciences 10, no. 11 (2020): 3923. http://dx.doi.org/10.3390/app10113923.
Full textAbstract:
In this study, carbon-supported Pt-based catalysts, including PtRu, PtRh, and PtRuRh nanorods (NRs), were prepared by the formic acid reduction method for ethanol oxidation reaction (EOR) application. The aspect ratio of all experimental NRs is 4.6. The X-ray photoelectron spectroscopy and H2-temperature-programmed reduction results confirm that the ternary PtRuRh has oxygen-containing species (OCS), including PtOx, RuOx and RhOx, on its surface and shows high EOR current density at 0.6 V. The corresponding physical structure results indicate that the surface OCS can enhance the adsorption of ethanol through bi-functional mechanism and thereby promote the EOR activity. On the other hand, the chronoamperometry (CA) results imply that the ternary PtRuRh has the highest mass activity, specific activity, and stability among all catalysts. The aforementioned pieces of evidence reveal that the presence of OCS facilitates the oxidation of adsorbed intermediates, such as CO or CHx, which prevents the Pt active sites from poisoning and thus simultaneously improves the current density and durability of PtRuRh NRs in EOR.
18
Lee, B. N., and J. C. Lou. "Study on wet air oxidation of aqueous ferrous cyanide solution catalyzed by three metal salts." Water Science and Technology 42, no. 3-4 (2000): 131–36. http://dx.doi.org/10.2166/wst.2000.0369.
Full textAbstract:
The catalytic wet oxidation (CWO) process with Cu2+, Mn2+, and Ce2+ as catalysts, respectively, was applied to investigate the degradation of ferrocyanide (Fe(CN)64-) solution. For the conversions of Fe(CN)-64- during the noncatalytic wet oxidation (WO) process up to 99.9% was attained after a reaction time of 70 min. The COD removal efficiency was observed as only 38% in a noncatalytic oxidation; however, it could be enhanced to 75%, 61%, and 50% in the presence of Cu2+, Mn2+, and Ce2+, respectively. Both noncatalytic and catalytic wet oxidation processes of Fe(CN)-64- solution were considered to be a two-step reaction at pH 9.0 and temperatures of 433-473 K. The oxidation rate was initially fast, followed by a slow step, which did obey first-order kinetics with respect to chemical oxygen demand (COD). Both the 2+ and Ce2+ catalyzed oxidation showed a significant effect on the reduction of activation energy during the first reaction of the WO runs.
19
Wang, Ying-Ying. "Theoretical study of the oxidation of formic acid on a PtPd(111) surface." Progress in Reaction Kinetics and Mechanism 44, no. 1 (2019): 67–73. http://dx.doi.org/10.1177/1468678319830512.
Full textAbstract:
By performing density functional theory calculations, the adsorption configurations of formic acid and possible reaction pathway for HCOOH oxidation on PtPd(111) surface are located. Results show that CO2 is preferentially formed as the main product of the catalytic oxidation of formic acid. The formation of CO on the pure Pd surface could not possibly occur during formic acid decomposition on the PtPd(111) surface owing to the high reaction barrier. Therefore, no poisoning of catalyst would occur on the PtPd(111) surface. Our results indicate that the significantly increased catalytic activity of bimetallic PtPd catalyst towards HCOOH oxidation should be attributed to the reduction in poisoning by CO.
20
Huang, Lin Lin, Jun Feng Liu, Bin Sun, Nan Zhang, Yong Qing Tang, and Yu Jie Feng. "Experimental Study on Papermaking Wastewater by Advanced Electrochemical Oxidation Method." Advanced Materials Research 726-731 (August 2013): 1699–703. http://dx.doi.org/10.4028/www.scientific.net/amr.726-731.1699.
Full textAbstract:
Papermaking wastewater effluent from a biological processing unit was treated by an advanced treatment method-electrochemical oxidation process. The experiments were carried out in an electrochemical reactor using RuO2\SnO2 coated on titanium as anode and stainless steel as cathode. The changes of Chemical Oxygen Demand (COD) reduction and other relative parameters have been determined as a function of treatment time and applied current density. The optimum reaction time and current density was 60min and 5mA/cm2, respectively. Results indicate that as an advanced treatment method, electrochemical oxidation can treat papermaking wastewater to achieve the standard of effluents effectively.
21
Haseneder, R., B. Fdez-Navamuel, and G. Härtel. "Degradation of polyethylene glycol by Fenton reaction: a comparative study." Water Science and Technology 55, no. 12 (2007): 83–87. http://dx.doi.org/10.2166/wst.2007.391.
Full textAbstract:
Photochemical advanced oxidation processes (AOPs) utilising different Fenton systems were investigated in laboratory-scale experiments for the degradation of polyethylene glycol (PEG). The results of the study showed that the degradation rate of PEG was strongly accelerated by the homogeneous system, and this proved to be advantageous in comparison to the heterogeneous system. Between Fenton and photo-Fenton heterogeneous systems, the photo-Fenton process reached the highest removal rate of the organic compound, due to the enhanced reduction efficiency of Fe(III) to Fe(II) under UV-irradiation. The oxidation rate in the heterogeneous system was investigated using varying different parameters, such as the pH value, the concentration of hydrogen peroxide and the amount of Fe(OH)3 as the catalyst. For the homogeneous Fenton system the rate of degradation is significantly higher. At the same time of operation the elimination rates can be found to be 30% over the rates of the heterogeneous system. Optimising the typical influence parameters mentioned before, a degradation of about 93% of PEG can be achieved by using the homogeneous Fenton system.
22
Liu, Biao, Shi Li Zheng, Hui Bin Liu, et al. "Comparison Study of the Electrochemical Behavior of Vanadate in NaOH and KOH Solutions." Advanced Materials Research 402 (November 2011): 66–73. http://dx.doi.org/10.4028/www.scientific.net/amr.402.66.
Full textAbstract:
The redox behavior of vanadate ions at glassy carbon electrode in KOH solutions with concentration ranging from 0.1M to 1M had been studied using cyclic voltammetry method. It is found out that vanadate ions experience similar redox reactions in both NaOH and KOH solutions, which involve a single cathodic reduction and two oxidation reactions in one cyclic sweep. Nearly same currents are obtained under the same reaction conditions in both solutions. However, vanadate ions appear more difficult to be reduced in KOH solutions than in NaOH solutions, and the reduction reaction exhibits higher irreversibility. The reduction potential is influenced by vanadate ions concentration, and is more negative in KOH solutions. The reversibility of reduction reaction is greatly dependent on alkalinity, and the reduction potential obviously decreases with the increase of alkalinity in KOH solutions. However, only a slight decrease was observed in NaOH solution, which may be due to the fact that OH-exhibits higher activity in KOH solutions.
23
Sambeth, Jorge, Alfredo Juan, Luis Gambaro, and Horacio Thomas. "Adsorption/Oxidation of CH3OH on V2O5. A Theoretical and Experimental Study." Adsorption Science & Technology 15, no. 7 (1997): 517–29. http://dx.doi.org/10.1177/026361749701500705.
Full textAbstract:
The adsorption/oxidation of CH3OH on V2O5 was studied in previous work by mass spectrometric analysis of the reaction atmosphere, and by measuring the electrical properties (Hall effect) and total pressure of the system. Such data allowed a reaction pathway to be proposed. In the present work, the variations in the surface oxidation number have been calculated via balances in the C and H atoms in the reaction atmosphere and models of the (010) plane of V2O5 and of CH3OH have also been utilized to find energetically favourable sites for the adsorption of CH3OH and its subsequent oxidation to H2CO. For this purpose, the variation in the total energy of the system was computed by Extended Hückel-type calculations (ASED, Atom Superposition and Electron Delocalization). From such experimental results, it was deduced that the H atoms are removed by the network oxygens and that methanol is adsorbed as the methoxy group. Such removal of H atoms has two consequences: high surface hydroxylation and surface reduction [V(5+) → V(4+)]. In support of these suggestions, the theoretical results have confirmed both the removal of H atoms and methoxy group formation, and have also revealed two possible adsorption sites for CH3OH on V2O5: the terminal oxygens (V=O) and the network bridging oxygens (V-O-V).
24
Polyakov, K. M., S. Gavryushov, S. Ivanova, et al. "Structural study of the X-ray-induced enzymatic reduction of molecular oxygen to water bySteccherinum murashkinskyilaccase: insights into the reaction mechanism." Acta Crystallographica Section D Structural Biology 73, no. 5 (2017): 388–401. http://dx.doi.org/10.1107/s2059798317003667.
Full textAbstract:
The laccase fromSteccherinum murashkinskyiis a member of the large family of multicopper oxidases that catalyze the oxidation of a wide range of organic and inorganic substrates, accompanied by the reduction of dioxygen to water. The reducing properties of X-ray radiation and the high quality of the laccase crystals allow the study of the catalytic reduction of dioxygen to water directly in a crystal. A series of diffraction data sets with increasing absorbed radiation dose were collected from a single crystal ofSteccherinum murashkinskyilaccase at 1.35 Å resolution. Changes in the active-site structure associated with the reduction of molecular oxygen to water on increasing the absorbed dose of ionizing radiation were detected. The structures in the series are mixtures of different states of the enzyme–substrate complex. Nevertheless, it was possible to interpret these structures as complexes of various oxygen ligands with copper ions in different oxidation states. The results allowed the mechanism of oxygen reduction catalyzed by laccases to be refined.
25
Wu, Yan Ni, Hai Fu Guo, Peng Hu, Xiao Peng Xiao, Zhao Wang Xiao, and Shi Jun Liao. "A Comparative Study on Ternary Low-Platinum Catalysts with Various Constructions for Oxygen Reduction and Methanol Oxidation Reactions." Nano 11, no. 07 (2016): 1650081. http://dx.doi.org/10.1142/s1793292016500818.
Full textAbstract:
Three types of ternary low-platinum nanocatalysts, alloy PdPtIr/C, core–shell PdPt@PtIr/C and Pd@PtIr/C, have been prepared, and their catalytic behaviors toward methanol oxidation reaction (MOR)/oxygen reduction reaction (ORR) are comparatively investigated via cyclic voltammetry and chronoamperometry analysis in an acidic medium. Through a two-step colloidal technique, the synthesized core–shell structured catalyst PtPd@PtIr/C with alloy core and alloy shell show the best catalytic activity toward MOR and the best poisoning tolerance. The alloy PdPtIr/C catalyst prepared via a one-step colloidal technique exhibits the best performance toward ORR among the three catalysts. All the three catalysts are characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and other characterization techniques.
26
Shan, Jinhuan, Fang Wang, Changying Song, and Heye Wang. "Kinetic and Mechanistic Study of the Reduction of Chromium(VI) by Lactic Acid." Research Letters in Inorganic Chemistry 2008 (December 28, 2008): 1–4. http://dx.doi.org/10.1155/2008/314045.
Full textAbstract:
The kinetics and mechanism of the reduction of chromium(VI) by lactic acid (Lac) in aqueous acidic medium was studied with spectrophotometry in a temperature range of 298.15 K~313.15 K. Under the conditions of the pseudo-first order , the observed rate constant increased with the increase in [Lac] and . There is no salt effect. Based on the experimental results, a probable reaction mechanism of oxidation was proposed. The rate equation derived from the mechanism could explain all the experimental phenomena. Activation parameters along with rate constant of the rate-determining step have been evaluated.
27
Arshad, Muhammad, Shah Zeb, Muhammad Atif Tauseef, and Najeeb Ullah. "Correlation of Serum Sodium with Severity of Hepatic Encephalopathy." Journal of Gandhara Medical and Dental Science 3, no. 01 (2016): 3–10. http://dx.doi.org/10.37762/jgmds.3-01.41.
Full textAbstract:
INTRODUCTIONHepatic encephalopathy (HE) is neuropsychiatric syndrome for which symptoms, manifested on a continuum, is deterioration in mental status, with psychomotor dysfunction, impaired memory, increase reaction time, poor concentration, disorientation, and in severe form coma and may develop at an annual rate of 8% in cirrhotic patients in Far Eastern studies. Fluctuation in serum sodium level is a frequent complication of advanced cirrhosis related to impairment in the renal capacity to eliminate solute-free water that causes retention of water that is disproportionate to the retention of sodium, thus causing a reduction in serum sodium concentration and hypo-osmolality. Hyponatremia is a common finding in patients with decompensated cirrhosis due to an abnormal regulation of body fluid homeostasis.OBJECTIVETo determine the correlation of serum sodium with severity of hepatic encephalopathyMATERIAL AND METHODSThis study was conducted at Naseer Teaching Hospital Peshawar. Duration of the study was 01 year and the study design was cross sectional (Correlation) study in which a total of 408 patients were observed by using – 0.1411 of correlation coefficient between serum sodium and hepatic encephalopathy 95% confidence level and 80% power of test. More over non probability consecutive sampling was used for sample collection.RESULTSIn this study mean age was 65 years with SD ± 0.315. Sixty two percent patients were male and 38% patients were female. Mean serum sodium level was 123 meq/L with SD ± 0.21. Five percent patients had severity of grade I, 39% patients had severity of grade II, 48% patients had severity of grade III and 8% patients had severity of grade IV. Correlation of severity of hepatic encephalopathy with serum sodium level was analyzed as all the 20 patients with severity of grade I had serum sodium level ranged 131-133 meq/L. All the 159 patients with severity of grade II had serum sodium level ranged 126-130 meq/L. In 196 patients with severity of grade III, 45 patients had serum sodium level ranged 126-130 meq/L while 151 patients had serum sodium level ranged 120-125 meq/L where as all the 33 patients with severity of grade IV had serum sodium level ranged 120-125 meq/L.CONCLUSIONHyponatremia was a common feature in patients with cirrhosis and its severity increased with the severity of liver disease. The existence of serum sodium concentration < 135 mmol/L was associated with greater frequency of hepatic encephalopathy. It was also noticed that more severe the hyponatremia, greater will be the grade of hepatic encephalopathy. Close monitoring of serum sodium concentration should be performed in patients with cirrhosis in order to prevent the rapid development of cirrhosis related complications.
28
Prazeres, Luz, Fernandes, and Jerónimo. "Reduction of Total Phenols, Total Phosphorus and Turbidity by Uncatalytic Oxidation Processes in Cheese Whey Wastewater." Proceedings 38, no. 1 (2020): 16. http://dx.doi.org/10.3390/proceedings2019038016.
Full textAbstract:
This study reports the first time that cheese whey wastewater has been treated by the hydrogen peroxide oxidation alone (uncatalytic reaction). This oxidation type was capable of eliminating the total phosphorus content in about 46–53%, regardless of the dose applied (1–7 g L−1). For total phenols contents, the oxidation system was capable of reducing around 40% under the lowest concentration investigated (1 g L−1). Similar results were obtained for calcium content with a reduction of 55%. Turbidity was reduced in about 90% when hydrogen peroxide was applied with concentrations of 2, 3 and 7 g L−1. Characteristic absorbances were reduced in the range of 12–83% depending on the operating conditions. Chemical oxygen demand (COD) was recalcitrant to hydrogen peroxide oxidation alone (uncatalytic reaction), needing a post-treatment.
29
Cihanoğlu, Aydın, Gönül Gündüz, and Meral Dükkancı. "Influence of ultrasound on the heterogeneous Fenton-like oxidation of acetic acid." Water Science and Technology 76, no. 10 (2017): 2793–801. http://dx.doi.org/10.2166/wst.2017.416.
Full textAbstract:
Abstract The main objective of this study is to investigate the effect of ultrasound on the heterogeneous Fenton-like oxidation of acetic acid, which is one of the most resistant carboxylic acids to oxidation. For this purpose, firstly, the degradation of acetic acid was examined by using ultrasound alone and the effects of different parameters such as: type of sonication system, ultrasonic power, and addition of H2O2 were investigated on the degradation of acetic acid. There was no chemical oxygen demand (COD) reduction in the presence of sonication alone. In the presence of the heterogeneous Fenton-like oxidation process alone, at 303 K, COD reduction reached only 7.1% after 2 h of reaction. However, the combination of the heterogeneous Fenton-like oxidation process with ultrasound increased the COD reduction from 7.1% to 25.5% after 2 h of reaction in an ultrasonic bath operated at 40 kHz, while the COD reduction only increased from 7.1% to 8.9% in the ultrasonic reactor operated at 850 kHz. This result indicates that the hybrid process of ultrasound and heterogeneous Fenton-like oxidation is a promising process to degrade acetic acid.
30
Tang, Lin Jun, Chang Shan Lv, Dong Wang Liu, et al. "Study on Synthesis of (R)-2,2-Dimethyl-3-(tert-butoxycarbonyl)-4-ethynylox-azolidine." Advanced Materials Research 781-784 (September 2013): 1180–83. http://dx.doi.org/10.4028/www.scientific.net/amr.781-784.1180.
Full textAbstract:
(R)-2,2-Dimethyl-3-(tert-butoxycarbonyl)-4-ethynylox-azolidine, an intermediate of the natural product jaspine B, which was isolated from various sponges and endowed with cytotoxic activity against several human carcinoma cell lines, was synthesized fromL-Serine in overall yield 43% through seven steps, including esterification, Boc protection, acetonization, reduction, Swern oxidation and Corey-Fuchs reaction.
31
Shu, Min-Fong, and Yi-Hsiu Tseng. "Copper Oxidation Effect in the EMC/Cu Interfacial Adhesion Improvement for a Novel Copper Interconnection Substrate Application." International Symposium on Microelectronics 2018, no. 1 (2018): 000161–66. http://dx.doi.org/10.4071/2380-4505-2018.1.000161.
Full textAbstract:
Abstract Copper oxidation structure, cupric oxide (CuO) and cuprous oxide (Cu2O), under Ar/H2 plasma reaction mechanism for the EMC/Cu interface adhesion improvement was studied in this work. This work is utilized TGA to figure out Cu oxidized state and sample preparation, and using plasma treatment Cu oxidation layer to evaluate the EMC/Cu interface adhesion strength by shear testing method. Results show a plasma reduction on Cu oxidation layer provide a better interface adhesion, and the layer structure has a significant composition change, Cu/Cu2O/CuO/EMC → Cu/Cu2O/CuO/Cu2O/EMC. These layer structures were identified by high-resolution TEM mapping with EELS spectrum fitting, it was also verified for CuO reduction to form Cu2O, following the Cu2O hydration would provide much hydrogen-bonding in the EMC/Cu interface. This kind of chain reaction mechanism including CuO reduction and Cu2O hydration was described by 2CuO + H2 → Cu2O +H2O → 2CuOH (hydration molecular). The reaction mechanism of the EMC/Cu bonding has been investigated and verified in this experimental study and our conclusion is that hydrogen bonding on the Cu oxidation layer surface can strengthen the EMC/Cu interface adhesion.
32
Junkaew, Anchalee, Supawadee Namuangruk, Phornphimon Maitarad, and Masahiro Ehara. "Silicon-coordinated nitrogen-doped graphene as a promising metal-free catalyst for N2O reduction by CO: a theoretical study." RSC Advances 8, no. 40 (2018): 22322–30. http://dx.doi.org/10.1039/c8ra03265c.
Full textAbstract:
Mechanistic insight into the N<sub>2</sub>O reduction and CO oxidation on SiN<sub>4</sub>G is reported in this theoretical study. The high reactive and selective SiN<sub>4</sub> center leads this metal-free catalyst as a promising catalyst for this reaction under mild conditions.
33
Li, C., and X. Z. Li. "Degradation of endocrine disrupting chemicals in aqueous solution by interaction of photocatalytic oxidation and ferrate (VI) oxidation." Water Science and Technology 55, no. 1-2 (2007): 217–23. http://dx.doi.org/10.2166/wst.2007.018.
Full textAbstract:
In this study, the degradation of bisphenol A in aqueous suspension by interaction of photocatalytic oxidation and ferrate(VI) oxidation was investigated under different conditions. The results indicate that the formation of Fe(V) and Fe(IV) is in the photocatalytic reduction of Fe(VI) by electron (e−cb) on the surface of TiO2. The oxidation efficiency of the photocatalytic oxidation in the presence of Fe(VI) was much greater than that without. In addition, the decomposition of Fe(VI) under different conditions was also investigated. The results indicate that the Fe(VI) reduction was accelerated by photocatalytic reaction and the adsorption capacity of Fe(VI) on TiO2 surface decreased as pH increased. The characteristics of solid potassium ferrate prepared were investigated by X-ray diffraction. It was found that the potassium ferrate solid has a tetrahedral structure with a space group of D2h (Pnma) and a=7.705 Å, b=5.863 Å, and c=10.36 Å.
34
Kawakita, Mamiko, Jin Kawakita, Yoshio Sakka, and Tadashi Shinohara. "Photoelectrochemical evaluation of anatase TiO2 polycrystalline aggregation layers with different crystalline orientations." Journal of Materials Research 25, no. 1 (2010): 63–68. http://dx.doi.org/10.1557/jmr.2010.0002.
Full textAbstract:
In order to evaluate the characteristics of photocatalysts such as TiO2, it is important to separately estimate the oxidation and reduction reaction rates, since the overall reaction rate is limited by the rate-determining step. In this study, photoelectrochemical techniques were applied to thin films of crystalline oriented anatase TiO2 with polycrystalline aggregations deposited on the transparent conductive oxide (TCO) glass substrate, fabricated by the electrophoretic deposition (EPD) in a strong magnetic field. The influence of the plane orientation on the photocatalytic reaction rates was discovered for both oxidation and reduction with respect to current through the electrochemical measurements. The maximum photocurrent for the (001) plane orientation is three times higher than that for the (100) plane orientation, and is comparable with that of the random orientation. The rate of the anodic reaction determines the rate of the overall photocatalytic reaction, therefore affecting the photopotential.
35
Ma, Yuyao, Yuxia Ma, Min Liu, et al. "Study on Nanofibrous Catalysts Prepared by Electrospinning for Methane Partial Oxidation." Catalysts 9, no. 5 (2019): 479. http://dx.doi.org/10.3390/catal9050479.
Full textAbstract:
Electrospinning is a simple and efficient technique for fabricating fibrous catalysts. The effects of preparation parameters on catalyst performance were investigated on fibrous Ni/Al2O3 catalysts. The catalyst prepared with H2O/C2H5OH solvent showed higher catalytic activity than that with DMF/C2H5OH solvent because of the presence of NiO in the catalyst prepared with DMF/C2H5OH solvent. The metal ion content of the precursor also influences catalyst properties. In this work, the Ni/Al2O3 catalyst prepared with a solution containing the metal ion content of 30 wt % demonstrated the highest Ni dispersion and therefore the highest catalytic performance. Additionally, the Ni dispersion decreased as calcination temperature was enhanced from 700 to 900 °C due to the increased Ni particle sizes, which also caused a high reduction temperature and low catalytic activity in methane partial oxidation. Finally, the fibrous Ni/Al2O3 catalysts can achieve high syngas yields at high reaction temperatures and high gas flow rates.
36
Chang, Yu-Hsu, Yu-Chuan Wu, Ya-Ting Hsu, Shih-Hao Huang, Yi-Chin Huang, and Hsin-Tien Chiu. "Gold nanospirals." RSC Advances 5, no. 92 (2015): 75268–71. http://dx.doi.org/10.1039/c5ra11492f.
Full text
37
Christian, S. G., B. W. Moore-Igwe, R. B. Jacob, T. Odinga, and E. M. Eze. "Quality Indicator Measures as It Affects Turnaround Time (TAT) in A Molecular Laboratory in Port Harcourt, Rivers State." European Journal of Clinical Medicine 2, no. 4 (2021): 6–9. http://dx.doi.org/10.24018/clinicmed.2021.2.4.109.
Full textAbstract:

 Background: Turnaround Time (TAT) is an important Quality Indicator in the medical laboratory. The Rivers State University Teaching Hospital (RSUTH) Polymerase Chain Reaction (PCR) laboratory was enrolled in the process of World Health Organisation (WHO) - Regional Office for Africa (AFRO) accreditation by FHi360 in preparation for the ISO 15189 accreditation in 2016. One of the services rendered in the laboratory is Early Infant Diagnosis (EID)/Dried Blood Spots (DBS) in Human Immunodeficiency Virus (HIV) exposed infants. Clinicians depend on these results to determine the next step for the management of HIV exposed Infants. This study is aimed at assessing the rate of sample rejection (SR), determine the effect of specific intervention on this rate and the effect of SR on TAT. Method: It involves the assessment of samples delivered to the RSUTH PCR Laboratory from January 2019 to March 2020. A baseline rate of sample rejection was established from January to July 2019. Interventional measures were put in place such as introducing the national algorithm for rejection and acceptance of samples, training was also done for EID sample collectors and a final assessment of changes in the rate of sample rejection was determined at the final period of January to March 2020.Results: During the baseline period, sample rejection rate started at 5% in February and went back to 0% in March. In April however, the rate of rejection increased to 9%. There was a decline in rejection rate to 5% and 7% in May and June respectively. A sudden spike in rejection occurred in July at a rate of 19%. The major reasons for sample rejection were DBS cards with insufficient blood spots, DBS cards with clots present in spots, DBS cards that have serum rings and grossly haemolysed DBS. After baseline data was collected and interventions put in place. Sample rejection rate drastically reduced to 1%, 0% and 0% respectively from January to March which is way below the maximum threshold of 2% as advocated by WHO. At baseline EID, TAT was longer than a month, however; with SR, the TAT increased to about seven weeks. The final assessment in March from this study showed a significant reduction in sample rejection to 0%.Conclusion and recommendations: This study has shown that quality improvement is achievable if interventional tools are utilized promptly. This will result in shorter TAT; fewer samples rejected and therefore prompt treatment of exposed infants thus reducing morbidity and mortality due to HIV.
38
Jagadeesh, R. "Mechanistic investigations of oxidation of isatins by sodium N-chlorobenzenesulfonamide in alkaline medium: A kinetic study." Open Chemistry 3, no. 3 (2005): 482–501. http://dx.doi.org/10.2478/bf02479277.
Full textAbstract:
AbstractOxidation of isatins (isatin, 5-methylisatin, 5-bromoisatin and 5-nitroisatin) to their anthranilic acids was performed efficiently with sodium N-chlorobenzenesulfonamide or chloramine-B (CAB) in alkaline medium at 35±0.1°C. The reactions follow identical kinetics for all the isatins, being first-order dependence each in [CAB]o and [Isatin]o and inverse fractional-order on [NaOH]. Addition of halide ions and benzenesulfonamide, reduction product of CAB, do not significantly affect the rate. Variation of ionic strength of the medium had no effect on the rate, while the dielectric effect is negative. The solvent isotope effect was studied using D2O. Activation parameters for the overall reaction have been computed. The rates satisfactorily correlate with the Hammett σ relationship and the reaction constant ρ is −0.31 signifies that electron releasing groups accelerate the reaction while the electron withdrawing groups retard the rate. Values of ΔH≠ and ΔS≠ are linearly related and an isokinetic relationship is observed with β=376 K, indicating the reaction is controlled by enthalpy. The stoichiometry of the title reaction is found to be 1∶1. Oxidation products of isatins were identified as their corresponding anthranilic acids and the yields were found to be around 90 %. The observed results have been explained by a plausible mechanism and the related rate law deduced. This method offers several advantages including high yield of the products, short reaction times, easier isolation of products, and stable, cost effective and relatively non-toxic reagents, which make the reaction process simple and smooth.
39
Chen, Chaochao, Jinhuan Shan, Xiaofang Li, and Dan Su. "Kinetics and Mechanism Study of Oxidation of Ethylenediamine and Ethanolamine by Potassium Ferrate (VI) in Alkaline Media." International Journal of Chemistry 10, no. 3 (2018): 53. http://dx.doi.org/10.5539/ijc.v10n3p53.
Full textAbstract:
In this work, the kinetics of oxidation of Ethylenediamine and Ethanolamine by Potassium Ferrate (VI) has been studied by using stop –flow spectrometer under alkaline media. The results show that the oxidation-reduction reaction is a first-order to reactant and a negative fraction order to [OH-]. A convincing mechanism involving a slow response as the rate-controlling step is proposed and the rate equations derived from the mechanism was shown to fit all the experimental observations. The rate constants of the rate-controlling step and the thermodynamic activation parameters were calculated.
40
Ren, Fengzhu, Jihua Zhang, Yuanxu Wang, and Wenzhi Yao. "A graphene-coupled Bi2WO6 nanocomposite with enhanced photocatalytic performance: a first-principles study." Physical Chemistry Chemical Physics 18, no. 20 (2016): 14113–21. http://dx.doi.org/10.1039/c6cp00458j.
Full textAbstract:
Under the built-in electric field and the band edge potential well in graphene/Bi<sub>2</sub>WO<sub>6</sub>, the photogenerated electrons in Bi<sub>2</sub>WO<sub>6</sub> can flow to graphene. Graphene can efficiently capture and transport photogenerated electrons. Photocatalytic oxidation and reduction reaction can occur on the surface of Bi<sub>2</sub>WO<sub>6</sub> and graphene, respectively.
41
Salleh, Hasiah, Nora'aini Ali, Chi Chin Yap, et al. "Determination of HOMO and LUMO Level of Polythiophene, Poly(3-Thiophene Acetic Acid), Polypyrrole and Chlorophyll via Cyclic Voltammetry Method." Solid State Phenomena 307 (July 2020): 207–16. http://dx.doi.org/10.4028/www.scientific.net/ssp.307.207.
Full textAbstract:
Cyclic voltammetry can be used to investigate the chemical reactivity of species ion via oxidation and reduction process. The purpose of this study is to determine the level energy of high occupied molecule orbital (HOMO) and low unoccupied molecule orbital (LUMO) in polythiophene (PT), Poly (3-thiophene acetic acid) (P3TAA), polypyrrole (PPY) and chlorophyll (Chlo) through oxidation and reduction of molecular ions by cyclic voltammetry method. PT, P3TAA, PPY and Chlo solutions were prepared in a solvent of acetonitrile at the concentration range of 10-2 to 10-4 M. The current-voltage measurements for these solutions are performed using cyclic voltammetry method on input voltage from -2.0 V to 2.0 V. The working electrode used is indium tin oxide (ITO). The result of voltammogram is showed that the activity of PT species were produced three oxidation and one reduction processes. The formal reduction potential, Eo¢ is 0.83 (positive) meaning that oxidation process was dominant. So that the reaction of PT species was exhibited irreversible electrochemical behavior. The reaction of P3TAA species was exhibited reversible electrochemical behavior, where the range value of oxidation, DEpa and reduction, DEpc were in range of 0.825 V to 1.120 V and -0.230 V to 0.131 V respectively. PYY species reaction was exhibited irreversible electrochemical behavior where two oxidation states occur within -0.145 V to -0.202 V and 0.870 V to 1.63 V respectively. The species activity of Chlo was exhibited irreversible electrochemical behavior where only the oxidation process was obviously appeared at range of 0.80 V to 0.95 V. The LUMO energy levels of PT, P3TAA PPY and Chlo were 5.84 eV, 5.34 eV, 1.10 eV and 3.85 eV respectively, while HOMO energy levels of PT, P3TAA PPY and Chlo were 4.61 eV, 4.25eV, 3.70 eV and 5.93 eV. The average value of energy gap of PT, P3TAA, PPY and Chlo were 1.23 eV, 1.08 eV, 2.23 eV and 1.10 eV respectively.
42
Simon, V., Y. Simon, G. Scacchi, and F. Baronnet. "Étude expérimentale et modélisation des réactions d'oxydation du n-pentane et du cyclopentane." Canadian Journal of Chemistry 75, no. 5 (1997): 575–84. http://dx.doi.org/10.1139/v97-068.
Full textAbstract:
The reduction of automotive emissions and the reformulation of gasoline composition require a better understanding of the combustion mechanism, in particular aiming at the determination of the influential reactions which are responsible for the onset of knock in spark ignition engines. We have studied the oxidation mechanism of two hydrocarbons of different research octane number: n-pentane (62) and cyclopentane (100). This work follows a previous study on the oxidation of n-heptane and isooctane. The experimental study was performed at 873 K in a jet-stirred flow reaction vessel. The reaction mechanisms of n-pentane and cyclopentane were analysed on a purely kinetic basis, derived from our experimental results, and were finally modelled by using a programme of simulation of reaction mechanisms. The different behaviour of these two hydrocarbons with respect to autoignition phenomena is mainly dependent on the relative concentration of resonance-stabilized radicals in the reaction medium. Keywords: oxidation reaction, n-pentane, cyclopentane, modelling, autoignition.
43
Li, Songfeng, Chunhua Zhang, Ao Zhou, et al. "Experimental and kinetic modeling study for N2O formation of NH3-SCR over commercial Cu-zeolite catalyst." Advances in Mechanical Engineering 13, no. 4 (2021): 168781402110106. http://dx.doi.org/10.1177/16878140211010648.
Full textAbstract:
In this paper, a systematic experimental and kinetic model investigation was conducted over Cu-SSZ-13 catalyst to study the DeNOx efficiency and N2O formation for selective catalytic reduction of NOx with NH3 (NH3-SCR). The kinetic model was developed for various reactions to take place in the NH3-SCR system, including NH3 adsorption/desorption, NH3 oxidation, NO oxidation, standard SCR, fast SCR, slow SCR and N2O formation reactions. In addition, the reaction of N2O formation from NH3 non-selective oxidation was taken into account. All the experiments were performed in a flow reactor with a feed stream near to the real application of diesel engine vehicles exhaust. The current model can satisfactorily predict the steady state conversion rate of various species at the reactor outlet and the effect of gas hourly space velocities and ammonia nitrogen ratio on N2O formation. The results show that the kinetic model can simulate the reaction process of the Cu-SSZ-13 catalyst well. This is significant for the optimization of NH3-SCR system for achieving the higher DeNOx efficiency and the lower N2O emission.
44
Dükkancı, Meral. "Heterogeneous sonocatalytic degradation of Bisphenol-A and the influence of the reaction parameters and ultrasonic frequency." Water Science and Technology 79, no. 2 (2019): 386–97. http://dx.doi.org/10.2166/wst.2019.065.
Full textAbstract:
Abstract In the present study, the sonocatalytic oxidation of Bisphenol-A (BPA) was investigated in the presence of a LaFeO3 perovskite catalyst. The effects of the reaction temperature, initial pH, catalyst loading, presence of inorganic anions and sonication source (power and frequency) on the removal of BPA using heterogeneous sonocatalytic process were investigated. Under the studied temperature range of 288–318 K, 308 K was selected as the optimum temperature and the highest BPA removal and total oxygen demand (TOC) reduction of, 95.8% and 30.4% were achieved at that temperature. The thermodynamic parameters were calculated in the studied temperature range of 288–308 K. It was seen that an acidic pH of 3.0 was favorable for the BPA oxidation with the highest BPA removal and TOC reduction of 95.4% and 31.5%, respectively. Doubling the catalyst amount from 0.25 g/L to 0.5 g/L increased the BPA removal degree from 81.6% to 90.8%. However, further increase in catalyst amount has no remarkable positive effect on the removal of BPA. The removal of BPA was described by the first order kinetics with an activation energy of 14.9 kJ/mol. The results obtained from this study showed that the LaFeO3 perovskite catalyst was a good sonocatalyst giving high oxidation rates of BPA.
45
Omran, Mamdouh, Timo Fabritius, Yaowei Yu, and Guo Chen. "Thermal and Mass Spectroscopic Analysis of BF and BOF Sludges: Study of Their Behavior under Air and Inert Atmosphere." Metals 10, no. 3 (2020): 397. http://dx.doi.org/10.3390/met10030397.
Full textAbstract:
Differential thermal analysis (DTA), thermogravimetry (TG), and mass spectrometry (MS) were used to study the thermal behavior of the blast furnace (BF) and basic oxygen furnace (BOF) sludges generated from the iron-making industry. The results indicated that under air atmosphere the two types of sludge are different in their thermal behavior. In BF sludge, the exothermic carbon gasification (CO/CO2) reaction dominated the process, while in BOF sludge, the significant reaction occurred at 755 °C and was associated with a slight mass gain owing to the partial oxidation of Fe3O4 to Fe2O3. Under inert atmosphere, the thermal behavior of both BF and BOF sludges were dominated by a reduction reaction. In BF sludge, the endothermic reactions ranged from 785 to 1115 °C due to the reduction of iron oxides as follows: Fe2O3 → Fe3O4 → FeO → Fe. A total mass loss of about 27.78% was observed in the TG curve. While in BOF sludge, the endothermic peaks corresponded to magnetite reduction to iron (Fe). The overall mass loss of the BOF was approximately 16.92%. The mass spectrum of gases evolution for both BF and BOF sludges revealed that CO/CO2 gases were released from the sludges.
46
Nair, Mahesh, and Stéphane Abanades. "Solid-State Redox Kinetics of CeO2 in Two-Step Solar CH4 Partial Oxidation and Thermochemical CO2 Conversion." Catalysts 11, no. 6 (2021): 723. http://dx.doi.org/10.3390/catal11060723.
Full textAbstract:
The CeO2/CeO2−δ redox system occupies a unique position as an oxygen carrier in chemical looping processes for producing solar fuels, using concentrated solar energy. The two-step thermochemical ceria-based cycle for the production of synthesis gas from methane and solar energy, followed by CO2 splitting, was considered in this work. This topic concerns one of the emerging and most promising processes for the recycling and valorization of anthropogenic greenhouse gas emissions. The development of redox-active catalysts with enhanced efficiency for solar thermochemical fuel production and CO2 conversion is a highly demanding and challenging topic. The determination of redox reaction kinetics is crucial for process design and optimization. In this study, the solid-state redox kinetics of CeO2 in the two-step process with CH4 as the reducing agent and CO2 as the oxidizing agent was investigated in an original prototype solar thermogravimetric reactor equipped with a parabolic dish solar concentrator. In particular, the ceria reduction and re-oxidation reactions were carried out under isothermal conditions. Several solid-state kinetic models based on reaction order, nucleation, shrinking core, and diffusion were utilized for deducing the reaction mechanisms. It was observed that both ceria reduction with CH4 and re-oxidation with CO2 were best represented by a 2D nucleation and nuclei growth model under the applied conditions. The kinetic models exhibiting the best agreement with the experimental reaction data were used to estimate the kinetic parameters. The values of apparent activation energies (~80 kJ·mol−1 for reduction and ~10 kJ·mol−1 for re-oxidation) and pre-exponential factors (~2–9 s−1 for reduction and ~123–253 s−1 for re-oxidation) were obtained from the Arrhenius plots.
47
Vietanti, Frizka, and Chen-Hao Wang. "PdFeCo Supported on N-rGO as a Bifunctional Catalyst for Methanol Oxidation and High Stability Oxygen Reduction Reaction." Journal of Energy Mechanical Material and Manufacturing Engineering 5, no. 2 (2020): 29. http://dx.doi.org/10.22219/jemmme.v5i2.11643.
Full textAbstract:
In this study, we have synthesized nitrogen doped reduced graphene oxide (N-rGO) supported ternary PdFeCo nanoparticle by three methods. A hydrothermal method to synthesize N-rGO, an emulsion method to synthesize PdFeCo nanoparticle, and a rota-evaporation to synthesize PdFeCo/N-rGO composite. A bifunctional PdFeCo/N-rGO exhibited excellent electrocatalytic activity towards both methanol oxidation and stability in oxygen reduction reaction (ORR). During methanol oxidation reaction, PdFeCo/N-rGO exhibited stronger methanol tolerance than Pt/C. In stability ORR, PdFeCo/N-rGO exhibited 2.85 times greater than Pt/C in ORR stability. The high performance of PdFeCo/N-rGO was attributed by strong bonding of structure. A strong bonding of transition metals in Pd based catalyst can servemethanol tolerance and stability during ORR activity.
48
Gao, Yan, Tao Luan, Mingyang Zhang, Wenke Zhang та Wenchen Feng. "Structure–Activity Relationship Study of Mn/Fe Ratio Effects on Mn−Fe−Ce−Ox/γ-Al2O3 Nanocatalyst for NO Oxidation and Fast SCR Reaction". Catalysts 8, № 12 (2018): 642. http://dx.doi.org/10.3390/catal8120642.
Full textAbstract:
A series of Mn−Fe−Ce−Ox/γ-Al2O3 nanocatalysts were synthesized with different Mn/Fe ratios for the catalytic oxidation of NO into NO2 and the catalytic elimination of NOx via fast selective catalytic reduction (SCR) reaction. The effects of Mn/Fe ratio on the physicochemical properties of the samples were analyzed by means of various techniques including N2 adsorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), H2-temperature-programmed reduction (TPR), NH3-temperature-programmed desorption (TPD) and NO-TPD, meanwhile, their catalytic performance was also evaluated and compared. Multiple characterizations revealed that the catalytic performance was highly dependent on the phase composition. The Mn15Fe15−Ce/Al sample with the Mn/Fe molar ratio of 1.0 presented the optimal structure characteristic among all tested samples, with the largest surface area, increased active components distributions, the reduced crystallinity and diminished particle sizes. In the meantime, the ratios of Mn4+/Mnn+, Fe2+/Fen+ and Ce3+/Cen+ in Mn15Fe15−Ce/Al samples were improved, which could enhance the redox capacity and increase the quantity of chemisorbed oxygen and oxygen vacancy, thus facilitating NO oxidation into NO2 and eventually promoting the fast SCR reaction. In accord with the structure results, the Mn15Fe15−Ce/Al sample exhibited the highest NO oxidation rate of 64.2% at 350 °C and the broadest temperature window of 75–350 °C with the NOx conversion >90%. Based on the structure–activity relationship discussion, the catalytic mechanism over the Mn−Fe−Ce ternary components supported by γ-Al2O3 were proposed. Overall, it was believed that the optimization of Mn/Fe ratio in Mn−Fe−Ce/Al nanocatalyst was an extremely effective method to improve the structure–activity relationships for NO pre-oxidation and the fast SCR reaction.
49
Cahayningrum, Retno Dwi, Muktiningsih Nurjayadi, and Arif Rahman. "PENGEMBANGAN E-MODULE KIMIA BERBASIS POGIL (PROCESS ORIENTED GUIDED INQUIRY LEARNING) PADA MATERI REAKSI REDUKSI-OKSIDASI SEBAGAI SUMBER BELAJAR SISWA." JRPK: Jurnal Riset Pendidikan Kimia 7, no. 1 (2017): 59–65. http://dx.doi.org/10.21009/jrpk.071.07.
Full textAbstract:
This study aims to produce chemical-based e-Module POGIL (Process Oriented Guided Inquiry Learning) on the material oxidation-reduction reaction as a viable source of student learning. This research method using research and development or research and development (R & D). Subjects in this study were students of SMK class X. Data analysis techniques using an assessment analysis of 10 validators consisting of 5 material and language experts, as well as 5 media experts. Analysis of expert validation test questionnaires, Student and teacher trials using questionnaires that were adopted from Puskurbuk and issued by BSNP. Applications used in the manufacture of e-Module is 3D PageFlip Professional 1.7.7. The results of the study show that: (1) Assessment of experts as a whole is obtained in the range of 70% to 90% with good to excellent interpretation, (2) Assessment of teachers and students on a small scale and large scale as a whole increases in the range 80% 90% with good to good interpretation. Thus, it can be concluded that the e-Module POGIL material based chemical oxidation-reduction reactions are very well developed and already eligible for use in the learning process and can be used as a source of independent study students.
 Keywords: e-Module, POGIL, oxidation-reduction reaction, learning resources, 3D PageFlip
50
Lin, Long Li, Guo Guang Liu, and Wen Ying Lv. "Simultaneous Oxidation of Citric Acid and Reduction of Copper Ion by TiO2 Photocatalysis." Advanced Materials Research 485 (February 2012): 253–56. http://dx.doi.org/10.4028/www.scientific.net/amr.485.253.
Full textAbstract:
The present study is targeted on the simulated wastewater containing Cu(Ⅱ), citric acid and TiO2 under UV illumination in the presence of oxygen and at acidic pH. The photocatalytic reaction obeys first-order kinetic equation. The influence of Cu(Ⅱ) on photocatalytic oxidation of citric acid and how citric acid will affect the treatment of Cu(II) were described. The result showed that the coexistence of Cu(Ⅱ) and citric acid was favourable to the photocatalytic oxidation and reduction. Cu(Ⅱ) reductive product was analyzed by using X-ray Photoelectron Spectroscopy.