scholarly journals Microbial redox interplay enhances biodiversity and ecosystem productivity

2021 ◽  
Author(s):  
Mayumi Seto ◽  
Michio Kondoh
Keyword(s):  
Redox Reactions ◽  
High Efficiency ◽  
Reaction Pathway ◽  
Mechanistic Model ◽  
Chemical Compounds ◽  
Metabolic Energy ◽  
Ecosystem Productivity ◽  
Oxidation Reduction ◽  
Intimate Life ◽  
Anaerobic Environment

Abstract A significant portion of the Earth’s biodiversity and biomass is from the subsurface biosphere, where chemotrophic microbial species harness diverse inorganic oxidation-reduction reactions (redox reactions) as a major source of metabolic energy while driving biogeochemical cycles. Given the limited availability of energy in the anaerobic environment, a fundamental question concerns what interplay between the chemical environment and chemotrophic community enables the persistence of whole biogeochemical systems. Here, using a thermodynamics-based mechanistic model that maps the interplay between diverse chemotrophic species and chemical compounds onto a redox network, we show that cycles of redox reactions mediate chemotrophic interactions in a way that increases the complexity of both redox reaction networks and microbial communities and enhances the community-level efficiency of energy metabolism. The high efficiency and complexity of biogeochemical systems arises from the self-organised ecological niche segmentation of microbes. More specifically, a consortium of chemotrophic species that subdivide a long-reaction pathway into shorter-reaction segments enhance each other’s population growth, replaces the species that monopolises the long-reaction pathway, and increases ecosystem productivity. An ecologically driven ‘division of metabolic labour’ in the chemotrophic community provides a novel mechanism through which an intimate life-environment interplay concurrently enhances biodiversity and ecosystem productivity.

scholarly journals The influence of different sludge concentrations on its dewaterability during bioleaching

2020 ◽  
Vol 81 (12) ◽  
pp. 2585-2598
Author(s):  
Wenfeng Yang ◽  
Liyuan Zeng ◽  
Weihao Zhang ◽  
Qiyong Yang ◽  
Tianfeng Wang ◽  
...  
Keyword(s):  
Extracellular Polymeric Substances ◽  
Reduction Potential ◽  
High Efficiency ◽  
Specific Resistance ◽  
Principal Component ◽  
Buffering Capacity ◽  
Capillary Suction ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Sludge Dewaterability

Abstract Bioleaching, a technologically and economically feasible technology, is considered as the high efficiency method to improve dewaterability in sewage sludge. The objective of this study was to investigate the effect of different sludge concentrations on bioleaching dewaterability and understand the mechanism of the effect of bioleaching on sludge dewaterability. Variation in pH, oxidation-reduction potential (ORP), capillary suction time (CST), specific resistance to filtration (SRF) and different fractions of extracellular polymeric substances (EPS) including slime EPS (S-EPS), loosely bound EPS (LB-EPS), and tightly bound EPS (TB-EPS) were determined. Different sludge concentrations (5, 10, 15, 20 and 30 g·L−1) were selected to investigate during bioleaching. Results indicated that sludge buffering capacity significantly inhibited bioleaching efficiency as sludge concentrations increased. Optimum enhancements in sludge dewaterability were observed during the 10 g·L−1 sludge concentration treatment, and reached a maximum when the pH was 2.11. The variation of different fractions of EPS revealed that the ratio of S-EPS/TB-EPS significantly affected sludge dewaterability. Principal component analysis and Pearson's correlation analysis both provided evidence that the higher TB-EPS followed by a very large reduction was positively correlated with sludge dewaterability. However, the increase of protein and DNA in S-EPS content was negatively correlated with sludge dewaterability.

Study of the Mechanism of Interaction of Microwave Plasma Discharge with Solutions of Organic Substances

2016 ◽  
Vol 685 ◽  
pp. 657-661 ◽  
Author(s):  
Ludmila N. Shiyan ◽  
Alexey G. Zherlitsyn ◽  
Seda O. Magomadova ◽  
Cyril S. Lazar
Keyword(s):  
Organic Compounds ◽  
Redox Reactions ◽  
Microwave Plasma ◽  
Plasma Discharge ◽  
Organic Substances ◽  
Air Plasma ◽  
Oxidation Reduction ◽  
Redox Indicator ◽  
Mechanism Of Interaction ◽  
Mechanism Of Oxidation

This paper reports about results describing the mechanism of oxidation-reduction reactions occurring in the microwave plasma interaction with organic compounds solutions. Air and argon were used as the plasma gases in the experiments on disrupture of aqueous liquid organic compounds. Application of inversible redox indicator of methylene blue (MB) showed that disrupture of organic substances in microwave plasma was based on redox reactions. It was found that MB highest efficiency in the solution took place when air plasma-supporting gas was used.

scholarly journals Studi Perbandingan Pengajaran Reaksi Reduksi Oksidasi Antara Cara Perubahan Bilangan Oksidasi dengan Cara Setengah Reaksi terhadap Hasil Belajar Siswa Kelas XII IPA 1 dan XII IPA 2

2021 ◽  
Vol 21 (1) ◽  
pp. 353
Author(s):  
Fauziah Fauziah
Keyword(s):  
Redox Reaction ◽  
Redox Reactions ◽  
Oxidation Number ◽  
Reduction Reactions ◽  
Reaction Method ◽  
Oxidation Reduction ◽  
Reaction Coefficient ◽  
Level Of Significance ◽  
Student Grades ◽  
Train Of Thought

Oxidation-Reduction Reactions (Redox) are one of the hardest reactions to equalize, this means that it is hard to determine the suitable Reaction Coefficient. An easier and more logical train of thought is to remember that a Reduction and an Oxidation reaction happens simultaneously. A Redox Reaction has two methods in order to equalize, that which is by using the “Change in Oxidation Number” method or the “Half-Reaction (Ion-Electron)” method. The students’ skills in completing a Redox Reaction can be observed in the grades that they have achieved. This observation is intended to find out if there is a difference in students’ grades if you were to teach them about the equalization of Redox Reactions using either of these two methods (the “Change in Oxidation Number” method and the “Half-Reaction” method).  The population in this observation consists of the students of Class XII IPA 1 and Class XII IPA 2 of SMAS PERTIWI Jambi that are studying Oxidation-Reduction Reactions. Sample members consist of the students of Class XII IPA 1 and the students of Class XII IPA 3 of SMAS Pertiwi Jambi. The measuring instrument used is a test that has fulfilled standards. Normality tests and Homogeneity tests of the sample in question has been done before the Hypothetical test was implemented.  The average grades of students using the “Change in Oxidation Number” method and the “Half-Reaction” method is 11.75 and 10.8 respectively. The T-value of calculations is approximately 1.81 while the T-value of tables is approximately 2.00. With the Level of Significance being 0.05.  From the data provided above, it can be concluded that there is no difference in student grades whether the “Change in Oxidation Numbers” method or the “Half-Reaction” method is used to equalize Redox Reactions in applicative aspects.

A new classification scheme for teaching reaction types in general chemistry

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Bin Wang
Keyword(s):  
General Chemistry ◽  
Chemical Reactions ◽  
Redox Reactions ◽  
Classification Scheme ◽  
College Level ◽  
New Classification ◽  
Acid Base ◽  
Oxidation Reduction ◽  
Upper Level ◽  
Nuanced Understanding

AbstractGeneral chemistry is a freshman-level class required for most science majors and pre-professional undergraduates. A variety of concepts are introduced in this course; among them, chemical reactions are fundamental, but remain a central topic. The author compared 10 textbooks widely used for college-level general chemistry courses. They all cover the three major classes of chemical reactions: precipitation reactions, acid-base reactions, and oxidation-reduction (redox) reactions. However, significant differences in the way these textbooks present the material may cause confusion and misunderstanding for students, including when they move to upper-level courses. The author suggests a modified reaction classification scheme for general chemistry courses, which will provide students a more complete and nuanced understanding of chemical reactions.

scholarly journals Synthesis and physicochemical properties 4-((R))amino)-5-methyl-4H-1,2,4-triazole-3-thiols

2018 ◽  
pp. 55-59
Author(s):  
T. V. Kravchenko ◽  
O. I. Panasenko ◽  
Ye. G. Knysh
Keyword(s):  
Physicochemical Properties ◽  
High Efficiency ◽  
Chemical Compounds ◽  
Biological Properties ◽  
Biologically Active ◽  
Physical Chemical ◽  
Medical University ◽  
New Compounds ◽  
Instrumental Methods ◽  
Derivatives Of

Purposeful synthesis of derivatives of 1,2,4-triazole is one of the most important branches of modern pharmaceutical science Modern pharmaceutical market of domestic medicines requires constant updates of existing range. It makes possible the synthesis of new compounds with a predicted biological activity. The main advantage of derivatives of 1,2,4-triazole is high efficiency and low toxic. That is promising factor for creation of new chemical compounds. Analysis of literary data of past few years has showed that there is not enough information about synthesis, physical, chemical and biological properties of derivatives of 4-amino-5-methyl-4H-1,2,4-triazole-3-thiol in the literature. So synthesis and further research of derivatives of 4-amino-5-methyl-4H-1,2,4-triazole-3-thiol is topical. The research took place at the Department of toxicological and inorganic Chemistry of Zaporizhzhia State Medical University (the head of the department – professor O. I. Panasenko). During the work the research were the physicochemical properties of newly synthesized of compounds in accordance with the methods described in the State Pharmacopoeia of Ukraine. As starting substance was used 4-amino-5-methyl-4H-1,2,4-triazole-3-thiol obtained by cyclization of of potassium 2-atsetilgidrazinkarboditioata in the medium hydrazine hydrate. It is planned to research of the compounds obtained in the antimicrobial, act-protective, antioxidative and hypolipidemic activity. 9 new compounds of ylidene derivatives of 4-amino-5-methyl-4H-1,2,4-triazole-3-thiol were synthesized in a research. The structure of the new synthesized of substances was confirmed by with by means of modern of instrumental methods analysis (1H-PMR-spectroscopy, chromato-mass-spectrometry, elemental analysis). The obtained data is possible to use in purposeful synthesis for the further research of biologically active compounds.

scholarly journals Долгоживущие центры фотокатализа, создаваемые в ZnO резонансным возбуждением экситона

2019 ◽  
Vol 61 (11) ◽  
pp. 2158
Author(s):  
В.В. Титов ◽  
А.А. Лисаченко ◽  
И.Х. Акопян ◽  
М.Э. Лабзовская ◽  
Б.В. Новиков
Keyword(s):  
Redox Reactions ◽  
Room Temperature ◽  
High Efficiency ◽  
Surface States ◽  
Surface Barrier ◽  
Exciton Energy ◽  
Environmental Cleanup ◽  
Carrier Recombination ◽  
Slow Surface ◽  
2D Structure

Along with TiO_2, ZnO is the main photocatalyst for a wide class of redox reactions used to convert light energy into chemical and for environmental cleanup. It has been shown that the creation in ZnO of surface intrinsic defects in ZnO i.e. vacancies in the anionic and cationic sublattices (F-type and V-type centers) - makes it possible to create long-lived (up to 10^3 s) photocatalysis centers and thus fundamentally (tens of times) to increase the quantum yield of reactions. Slow surface states — photocatalysis centers — are created by the diffusion of electrons and holes generated during interband transitions in the volume of the photoactivated sample. However, the transfer efficiency is sharply reduced due to carrier recombination and losses when overcoming the Schottky surface barrier. In this work, In order to reduce these losses during energy transfer to the surface, we used in this work neutral energy carriers — excitons. The high (60 meV) exciton binding energy in ZnO allows it to move at room temperature without decay. The radiation loss of the exciton energy in our experiments is effectively reduced by the formation of a surface 2D structure. The results obtained confirm the high efficiency of the exciton channel for the formation of surface long-lived F and V centers of photocatalysis in the processes of oxygen photoadsorption and photodesorption, imitating the full cycle of the redox photocatalytic reaction.

scholarly journals Selective catalysis remedies polysulfide shuttling in lithium-sulfur batteries

2020 ◽  
Author(s):  
Wuxing Hua ◽  
Huan Li ◽  
Chun Pei ◽  
Jingyi Xia ◽  
Yafei Sun ◽  
...  
Keyword(s):  
Redox Reactions ◽  
Elemental Sulfur ◽  
Reaction Pathway ◽  
Proof Of Concept ◽  
Capacity Fading ◽  
Shuttle Effect ◽  
Lithium Sulfur Batteries ◽  
Selective Catalysis ◽  
Solid Liquid ◽  
Areal Capacity

Abstract The shuttling of soluble lithium polysulfides between the electrodes leads to serious capacity fading and excess use of electrolyte, which severely bottlenecks practical use of Li-S batteries. Here selective catalysis is proposed as a fundamental remedy for the consecutive solid-liquid-solid sulfur redox reactions. The proof-of-concept In2O3 catalyst targetedly slows down the solid-liquid conversion, dissolution of elemental sulfur to polysulfides, while accelerates the liquid-solid conversion, deposition of polysulfides into insoluble Li2S, which basically reduces accumulation of polysulfides in electrolyte, finally inhibiting the shuttle effect. The selective catalysis is revealed, experimentally and theoretically, by changes of activation energies and kinetic currents, modified reaction pathway together with the probed LiInS2 intermediates, and gradual deactivation of the catalyst. The In2O3-catalysed Li-S battery works steadily over 1000 cycles at 4.0 C and yields an initial areal capacity up to 9.4 mAh cm−2 with a sulfur loading of ~9.0 mg cm−2.

An Environment-Friendly Method to Catalytically Oxidate NO in Waste Water by Supported Manganese Oxide on Graphite Oxide

2015 ◽  
Vol 768 ◽  
pp. 3-9 ◽  
Author(s):  
Rui Jing Su ◽  
Min Cong Zhu ◽  
Xiu Zhi Sun ◽  
Jie Guan
Keyword(s):  
Manganese Oxide ◽  
Catalytic Oxidation ◽  
High Efficiency ◽  
Advanced Oxidation Process ◽  
Catalyst System ◽  
Complex Compounds ◽  
No Oxidation ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Oxidation Of No

In order to generate powerful radicals as oxidizing species for the complete oxidation of NO, homogeneous activation of peroxymonosulfate (Oxone: PMS) by the Mn3O4/GO catalysts was explored. The catalytic oxidation of NO from waste gas was investigated using advanced oxidation process based on sulfate radicals that produced. The manganese oxide immobilized on graphene oxide (GO) can activate PMS for the oxidation of NO in water. We not only took advantage of the high oxidation–reduction potential of produced sulfite radicals but also an opportunity to oxidize NO on less complex compounds with low dosages. The Mn3O4/GO catalysis system was characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that Mn3O4was well-distributed on GO. The Mn3O4/GO catalyst system exhibited high efficiency for NO oxidation when the Mn3O4/GO catalyst has an optimum Mn3O4loading. In addition, the best catalytic oxidation can be achieved within 30 min with pH 4 and 6 mM PMS at 25 °C. Therefore, the results indicate promising potential for a system utilizing Mn3O4/PMS to oxidize NO for offgas treatment.

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