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G. Velvizhi

Bio: G. Velvizhi is an academic researcher from VIT University. The author has contributed to research in topics: Microbial fuel cell & Wastewater. The author has an hindex of 16, co-authored 36 publications receiving 1373 citations. Previous affiliations of G. Velvizhi include Indian Institute of Chemical Technology.

Papers
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TL;DR: In this paper, an overview on the fundamental operational mechanism of MFC encompassing electromotive force, electron delivery, electron transfer, losses encountered during operation, and specific function of physical, biological and operational factors on the bioelectrogenic activity is elaborated.
Abstract: Microbial fuel cells (MFC) are bio-catalyzed electrochemical hybrid systems which function by converting chemical energy to electrical energy through a cascade of redox reactions in the presence of biocatalyst. The research on MFC has been intensified in the last few years due to its inherent ability to produce sustainable energy from renewable organic waste. The current review depicts an overview on the fundamental operational mechanism of MFC encompassing electromotive force, electron delivery, electron transfer, losses encountered during operation, etc. The specific function of physical, biological and operational factors on the bioelectrogenic activity is elaborated. In addition, the strategies to regulate the process towards enhancing the performance of the system have been discussed. The potential applications of MFC for energy generation, waste remediation and value added product recovery have also been elaborated.

300 citations

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TL;DR: Four conceptual models forCO2 biosequestration and the synthesis of biobased products, as well as an integrated CO2 biorefinery model, are proposed and might overcome the limitations of existing sequestration methods and could help realign the carbon balance.

221 citations

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TL;DR: This review addresses the contemporary progress and advances made in MCES, focusing on its application towards value addition and waste remediation.

176 citations

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TL;DR: In this article, a review of the challenges and strategies to improve the performance of bio-electrocatalyzed systems with respect to the operational, physico-chemical and biological factors is presented.
Abstract: Microbial electrochemical technologies have gained much attention in the recent years during which basic research has been carried out to provide proof of concept by utilizing microorganisms for generating bioenergy in an electro redox active environment. However, these bio-electrocatalyzed systems pose significant challenges towards up-scaling and practical applications. Various parameters viz., electrodes, materials, configuration, biocatalyst, reaction kinetics, fabrication and operational costs, resistance for electron transfer etc. will critically govern the performance of microbial catalyzed electrochemical systems. Majorly, the surface area of electrode materials, biofilm coverage on the electrode surface, enrichment of electrochemically active electrode respiring bacteria and reduction reactions at cathode will aid in increasing the reaction kinetics towards the upscaling of microbial electrochemical technologies. Enrichment of electroactive microbial community on anode electrode can be promoted with electrode pretreatment, controlled anode potential or electrical current, external resistance, optimal operation temperature, chemical additions and bioaugmentation . Inhibition of the growth of methanogens also increases the columbic efficiency, an essential parameter that determines the efficacy of bioelectricity generation. Considering the practical implementation of these microbial electrochemical technologies, the current review addresses the challenges and strategies to improve the performance of bio-electrocatalyzed systems with respect to the operational, physico-chemical and biological factors towards scale up. Besides, the feasibility for long term operation, the scope for future research along with the operational and maintenance costs are discussed to provide a broad spectrum on the role of the system components for the implementation of these bio-electrochemical technologies for practical utility.

169 citations

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TL;DR: In this article, the performance of a single chamber non-catalyzed microbial fuel cell (MFC, open-air cathode) was evaluated at four organic loads employing anaerobic mixed consortia as anodic biocatalyst.

165 citations


Cited by
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TL;DR: In this article, the authors introduce the thermodynamics, reaction kinetics, reaction mechanisms, and reaction pathways of ORR in aqueous alkaline media, and summarize the current status of the reaction pathways, advanced catalysts, and the future challenges of the research and development of the ORR.
Abstract: The oxygen reduction reaction (ORR) is an important electrode reaction for energy storage and conversion devices based on oxygen electrocatalysis. This paper introduces the thermodynamics, reaction kinetics, reaction mechanisms, and reaction pathways of ORR in aqueous alkaline media. Recent advances of the catalysts for ORR were extensively reviewed, including precious metals, nonmetal-doped carbon, carbon–transition metal hybrids, transition metal oxides with spinel and perovskite structures, and so forth. The applications of those ORR catalysts to zinc–air batteries and alkaline fuel cells were briefly introduced. A concluding remark summarizes the current status of the reaction pathways, advanced catalysts, and the future challenges of the research and development of ORR.

949 citations

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TL;DR: This review illustrates different bioprocess based technological models that will pave sustainable avenues for the development of biobased society through closed loop approach wherein waste is valorised through a cascade of various biotechnological processes addressing circular economy.

603 citations

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TL;DR: In this article, the fundamental principles and applications of heterogeneous electrochemical wastewater treatment based on Fenton's chemistry reaction are discussed and the required features of good heterogeneous catalysts are discussed, followed by the mechanisms of catalytic activation of H2O2 to reactive oxygen species (ROS) especially hydroxyl radical ( OH) by heterogeneous catalyst in Hetero-EF system.
Abstract: This exhaustive review focuses on the fundamental principles and applications of heterogeneous electrochemical wastewater treatment based on Fenton’s chemistry reaction. The elementary equations involved in formation of hydroxyl radical in homogeneous electro-Fenton (EF) and photo electro-Fenton (PEF) processes was presented and the advantages of using insoluble solids as heterogeneous catalyst rather than soluble iron salts (heterogeneous electro-Fenton process) (Hetero-EF) was enumerated. Some of the required features of good heterogeneous catalysts were discussed, followed by the mechanisms of catalytic activation of H2O2 to reactive oxygen species (ROS) especially hydroxyl radical ( OH) by heterogeneous catalyst in Hetero-EF system. Extensive discussion on the two configuration of Hetero-EF system vis-a-vis added solid catalysts and functionalized cathodic materials were provided along with summaries of some relevant studies that are available in literature. The solid catalysts and the functionalized cathodic materials that have been utilized in Hetero-EF wastewater treatment were grouped into different classes and brief discussion on their synthesis route were given. Besides, the use of solid catalysts and iron-functionalized cathodic materials in bioelectrochemical system (BES) especially bioelectro-Fenton technology (BEF) using microbial fuel cells (MFCs) with concurrent electricity generation for Hetero-EF treatment of biorefractory organic pollutants was discussed. In the final part, emphasis was made on the challenges and future prospects of the Hetero-EF for wastewater treatment.

574 citations

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TL;DR: In this paper, the performance of different types (designs) of MFCs in terms of electric current and power outputs together with the wastewater treatment efficiency, including chemical oxygen demand (COD) removal and columbic efficiency (CE), is presented.

569 citations

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TL;DR: From the present study, it can be conclude that Fenton processes are very effective and environmentally friendly methods for dye removal.
Abstract: Several industries are using dyes as coloring agents. The effluents from these industries are increasingly becoming an environmental problem. The removal of dyes from aqueous solution has a great potential in the field of environmental engineering. This paper reviews the classification, characteristics, and problems of dyes in detail. Advantages and disadvantages of different methods used for dye removal are also analyzed. Among these methods, Fenton process-based advanced oxidation processes are an emerging prospect in the field of dye removal. Fenton processes have been classified and represented as “Fenton circle”. This paper analyzes the recent studies on Fenton processes. The studies include analyzing different configurations of reactors used for dye removal, its efficiency, and the effects of various operating parameters such as pH, catalyst concentration, H2O2 concentration, initial dye concentration, and temperature of Fenton processes. From the present study, it can be conclude that Fenton processes are very effective and environmentally friendly methods for dye removal.

540 citations