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Author

George Jacob

Bio: George Jacob is an academic researcher from VIT University. The author has contributed to research in topic(s): Graphene & Tafel equation. The author has an hindex of 7, co-authored 14 publication(s) receiving 823 citation(s).

Papers
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Abstract: Water pollution by various toxic contaminants has become one of the most serious problems worldwide. Various technologies have been used to treat water and waste water including chemical precipitation, ion-exchange, adsorption, membrane filtration, coagulation–flocculation, flotation and electrochemical methods. From past few decades, nanotechnology has gained wide attention and various nanomaterials have been developed for the water remediation. In the present review article, various nanomaterials have been reviewed which have been used for water decontamination. The special emphasis in the review has been given on adsorption, photocatalytic and antibacterial activity of nanomaterials.

667 citations

Journal ArticleDOI
TL;DR: Overall, this work provides an in depth analysis of the science behind the components of an electrochemical energy-storage system as well as why the different characterization techniques are required to assess the quality and reliability of the material for electrochemical supercapacitor applications.
Abstract: With every moving day, the aspect that is going to be the most important for modern science and technology is the means to supply sufficient energy for all the scientific applications. As the resource of fossil fuel is draining out fast, an alternative is always required to satisfy the needs of the future world. Limited resources also force to innovate something that can utilise the resource more efficiently. This work is based on a simple synthesis route of biomass derived hard carbon and to exploring the possibility of using it as electrochemical supercapacitors. A cheap, eco-friendly and easily synthesized carbon material is utilized as electrode for electrochemical energy-storage. Four different hard carbons were synthesized from KOH activated banana stem (KHC), phosphoric acid treated banana stem derived carbons (PHC), corn-cob derived hard carbon (CHC) and potato starch derived hard carbons (SHC) and tested as supercapacitor electrodes. KOH-activated hard carbon has provided 479.23 F/g specific capacitance as calculated from its cycle voltammograms. A detailed analysis is done to correlate the results obtained with the material property. Overall, this work provides an in depth analysis of the science behind the components of an electrochemical energy-storage system as well as why the different characterization techniques are required to assess the quality and reliability of the material for electrochemical supercapacitor applications.

87 citations

Journal ArticleDOI
Abstract: Hydrogen is one of the sustainable and promising carriers for the renewable electricity storage. In this context, Hydrogen Evolution Reaction (HER) takes regained interest than the Oxygen evolution reaction. Besides the noble metals, carbon based materials are found to be effective for catalyzing these reactions. The metal encapsulated with graphitic layers shows good activities towards HER. In the present work, cuprous oxide encapsulated with graphitic carbon nitride was synthesized and further structural and morphological properties were analyzed by XRD, SEM and BET. The as synthesized Cu2O/g-C3N4 served as electrodes for electrochemical hydrogen evolution reaction. The synthesized Cu2O/g-C3N4 composites show better electrochemical surface area and enhanced electrocatalytic behavior (148.7 mV over-potential with an exchange current density of 12.8 mA cm−2 and a Tafel slope 55 mV/dec) in alkaline medium.

16 citations

Journal ArticleDOI
21 Jul 2020
TL;DR: The present study reports the synthesis of a porous Fe-based MOF named MIL-100(Fe) by a modified hydrothermal method without the HF process, demonstrating as an excellent electrocatalyst for the hydrogen evolution reaction investigated in both acidic and alkaline media.
Abstract: The present study reports the synthesis of a porous Fe-based MOF named MIL-100(Fe) by a modified hydrothermal method without the HF process. The synthesis gave a high surface area with the specific surface area calculated to be 2551 m2 g-1 and a pore volume of 1.407 cm3 g-1 with an average pore size of 1.103 nm. The synthesized electrocatalyst having a high surface area is demonstrated as an excellent electrocatalyst for the hydrogen evolution reaction investigated in both acidic and alkaline media. As desired, the electrochemical results showed low Tafel slopes (53.59 and 56.65 mV dec-1), high exchange current densities (76.44 and 72.75 mA cm-2), low overpotentials (148.29 and 150.57 mV), and long-term stability in both media, respectively. The high activity is ascribed to the large surface area of the synthesized Fe-based metal-organic framework with porous nature.

10 citations


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TL;DR: Detailed information and review on the adsorption of noxious heavy metal ions from wastewater effluents using various adsorbents - i.e., conventional (activated carbons, zeolites, clays, biosorbents, and industrial by-products) and nanostructured (fullerenes, carbon nanotubes, graphenes) is presented.
Abstract: The problem of water pollution is of a great concern. Adsorption is one of the most efficient techniques for removing noxious heavy metals from the solvent phase. This paper presents a detailed information and review on the adsorption of noxious heavy metal ions from wastewater effluents using various adsorbents – i.e., conventional (activated carbons, zeolites, clays, biosorbents, and industrial by-products) and nanostructured (fullerenes, carbon nanotubes, graphenes). In addition to this, the efficiency of developed materials for adsorption of the heavy metals is discussed in detail along with the comparison of their maximum adsorption capacity in tabular form. A special focus is made on the perspectives of further wider applications of nanostructured adsorbents (especially, carbon nanotubes and graphenes) in wastewater treatment.

702 citations

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Abstract: Among the popular photocatalysts, ZnO is one of the most potent photocatalysts considering its green properties, cheap price, and durability. However, the practical application of ZnO is limited because of its large band gap energy and rapid recombination of the photoinduced electron–hole pairs. This paper reviews the main advancements in overcoming the barriers accompanied by pure ZnO and the criteria for fabrication of effective visible-light-responsive ZnO-based photocatalysts. Herein, the binary ZnO-based nanocomposites with p–n heterojunctions, n–n heterojunctions, and ternary ZnO-based nanocomposites based on different heterostructures, and their mechanism for enhanced light harvesting and charge separation/transfer were thoroughly discussed.

580 citations

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TL;DR: Adsorption is a promising method worldwide for EC removal since it is low initial cost for implementation, highly-efficient and has simple operating design.
Abstract: Emerging contaminants (EC's) are pollutants of growing concern. They are mainly organic compounds such as: pesticides, pharmaceuticals and personal care products, hormones, plasticizers, food additives, wood preservatives, laundry detergents, surfactants, disinfectants, flame retardants, and other organic compounds that were found recently in natural wastewater stream generated by human and industrial activities. A majority of ECs does not have standard regulations and could lead to lethal effects on human and aquatic life even at small concentrations. The conventional primary and secondary water treatment plants do not remove or degrade these toxic pollutants efficiently and hence need cost effective tertiary treatment method. Adsorption is a promising method worldwide for EC removal since it is low initial cost for implementation, highly-efficient and has simple operating design. Research has shown that the application of different adsorbents such as, activated carbons(ACs), modified biochars (BCs), nanoadsorbents (carbon nanotubes and graphene), composite adsorbents, and other are being used for EC's removal from water and wastewater. The current review intends to investigate adsorption process as an efficient method for the treatment of ECs. The mechanism of adsorption has also been discussed.

384 citations

Journal ArticleDOI
TL;DR: In this review, the key advancement on the preparation and modification of novel adsorbents and their adsorption capacities for dyes removal under various conditions have been highlighted and discussed.
Abstract: Dyeing wastewaters are toxic and carcinogenic to both aquatic life and human beings. Adsorption technology, as a facile and effective method, has been extensively used for removing dyes from aqueous solutions for decades. Numerous researchers have attempted to seek or design alternative materials for dye adsorption. However, using various novel adsorbents to remove dyes has not been extensively reviewed before. In this review, the key advancement on the preparation and modification of novel adsorbents and their adsorption capacities for dyes removal under various conditions have been highlighted and discussed. Specific adsorption mechanisms and functionalization methods, particularly for increasing adsorption capacities are discussed for each adsorbent. This review article mainly includes (1) the categorization, side effects and removal technologies of dyes; (2) the characteristics, advantages and limitations of each sort of adsorbents; (3) the functionalization and modification methods and controlling mechanisms; and (4) discussion on the problems and future perspectives about adsorption technology from adsorbents aspects and practical application aspects.

344 citations

Journal ArticleDOI
Abstract: There are number of water purification techniques but the adsorption is one of the most simplest, effective and economical method for wastewater purification. In this article a large number of solid adsorbents such as Natural adsorbents, Agricultural Wastes, Industrial wastes, Biomass, Nanoadsorbents: Carbon based nanomaterials, Nobel metal based nanomaterials, Metal oxide based nanomaterials, Spinel ferrite based nanomaterials, Nanocomposites, Dendritic polymers; Geopolymer cement have been discussed for the removal of different pollutants from waste water. Removal of Fluoride, Phosphate, Nitrate and Radionuclides from wastewater has also been reviewed in this article. Adsorption isotherm models, kinetic models, thermodynamic parameters and adsorption mechanism have also been discussed. The present article lists different type of adsorbents and reviews state-of-the-art of the removal of different pollutants from water. The efforts have been made to discuss the sources of contamination and toxicities of pollutants. Adsorption mechanisms responsible for pollutants removal by different adsorbents have been reviewed. Attempts have also been made to point out the advantages and drawbacks of adsorbents and the future research needs in the area of water purification by adsorbents.

335 citations