Browsing by Author "Verma, Satish Kumar"
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Publication Carbon nanotubes for CO2 capture and conversion(Elsevier, 2022) Verma, Satish Kumar; Tripathi, Prashant; Bhatnagar, AshishIt is now generally accepted that carbon emissions from the burning of fossil fuels and changes in land use are causing atmospheric CO2 levels to rise rapidly, resulting in an increase in the impact of greenhouse gases (GHGs) due to climate change. Carbon Capture and Storage and later on conversion to a valuable fuel by adsorption in carbon nanomaterials is an attractive approach to mitigate future global climate change and is generally accepted as a viable road to sustainable fossil fuel usage. Out of the various carbon nanomaterials, carbon nanotubes (CNT) are the front-running candidates owing to their classical performance as adsorbents. CNTs are pure carbon cylinders with a radius of a few nm and variable lengths (100nm to mm). CNTs are extraordinarily light and highly porous and very suitable for gas storage applications due to their high surface area. CNTs also have elevated conductivity (thermal and electrical) and are rich in chemistry. The properties mentioned above make them a competent candidate for CO2 adsorption and desorption, efficiently and selectively. This chapter will discuss the state-of-the-art CNTs used for carbon capture and prospects of the same. � 2023 Elsevier Inc. All rights reserved.Publication Catalytic characteristics of titanium-(IV)-isopropoxide (TTIP) on de/re-hydrogenation of wet ball-milled MgH2/Mg(John Wiley and Sons Ltd, 2022) Pandey, Sunita Kumari; Verma, Satish Kumar; Bhatnagar, Ashish; Yadav, Thakur PrasadMagnesium hydride (MgH2) has received much attention as a solid-state hydrogen storage material worldwide due to its high hydrogen storage capacity, good reversibility, and low cost. However, its practical application has been limited due to its high thermodynamic stability and slow kinetics. In the present work, we have employed a new type of catalyst, Titanium-tetra-isopropoxide (TTIP) (Ti(OC3H7)4), to catalyze MgH2. To disperse the catalyst evenly over the MgH2, the milling operation was conducted using tetrahydrofuran (THF) as a process control agent. Here, using THF as the process control agent during the wet ball milling along with TTIP of MgH2 itself used to improve the de/re-hydrogenation behavior of MgH2. A de/re-hydrogenation investigation demonstrates that MgH2 catalyzed by TTIP has better hydrogen storage properties (onset dehydrogenation temperature 210�C) than as-cast MgH2 (onset dehydrogenation temperature ~400�C). Furthermore, a remarkable catalytic behavior of TTIP on MgH2 was observed during de-/re-hydrogenation kinetics (absorb the hydrogen ~4.6�wt% within the 1.5�minutes at a temperature of 300�C under a hydrogen pressure of 20 atm and release the hydrogen of ?4.98 wt% within 5�minutes at ?300�C) due to formation of intermediate compound Mg1?xTixO, and it retains nearly constant hydrogen storage capacity (from 5.25 to 5.20 wt% in rehydrogenation and from 4.95 wt % to 4.95 wt% in dehydrogenation) up to 60 cycles of de/re-hydrogenation. The estimated desorption activation energy for MgH2-TTIP using Arrhenius equation is 77.67 kJ/mol. The reason for de/re-hydrogenation kinetics improvement of MgH2-TTIP can be seen in the mechanism. � 2022 John Wiley & Sons Ltd.Publication Editorial: Seed Microbiome Research(Frontiers Media S.A., 2022) Jonkers, Wilfried; Gundel, Pedro E.; Verma, Satish Kumar; White, James Francis[No abstract available]Publication Enhanced hydrogen absorption and desorption properties of MgH2 with graphene and vanadium disulfide(Elsevier Ltd, 2023) Verma, Satish Kumar; Shaz, Mohammad Abu; Yadav, Thakur PrasadMagnesium hydride (MgH2) is the most prominent carrier for storing hydrogen in solid-state mode. However, their slow kinetics and high thermodynamics become an obstacle in hydrogen storage. The present study elaborates on the catalytic effect of graphene (Gr) and vanadium disulfide (VS2) on MgH2 to enhance its hydrogen sorption kinetic. The temperature-programmed desorption study shows that the onset desorption temperature of MgH2 catalyzed by VS2 and MgH2 catalyzed by Gr is 289 �C and 300 �C, respectively. These desorption temperatures are 87 �C and 76 �C lower than the desorption temperature of pristine MgH2. The rapid rehydrogenation kinetics for the MgH2 catalyzed by VS2 have been found at a temperature of 300 �C under 15 atm H2 pressure by absorbing ?4.04 wt% of hydrogen within 1 min, whereas the MgH2 catalyzed by Gr takes ?3 min for absorbing the same amount of hydrogen under the similar temperature and pressure conditions. The faster release of hydrogen was also observed in MgH2 catalyzed by VS2 than MgH2 catalyzed by Gr and pristine MgH2. MgH2 catalyzed by VS2 releases ?2.54 wt% of hydrogen within 10 min, while MgH2 catalyzed by Gr takes ?30 min to release the same amount of hydrogen. Furthermore, MgH2 catalyzed by VS2 also persists in the excellent cyclic stability and reversibility up to 25 cycles. � 2022 Hydrogen Energy Publications LLCPublication Facile synthesis of M2(m-dobdc) (M�=�Fe and Mn) metal-organic frameworks for remarkable hydrogen storage(John Wiley and Sons Inc, 2022) Verma, Satish Kumar; Shaz, Mohammad Abu; Yadav, Thakur PrasadMetal-organic frameworks (MOFs) are emerging as promising candidates for hydrogen storage material because of their porosity and adjustable hydrocarbon structures coordinated with the metal element. Present work explore the synthesis of M2(m-dobdc) (M�=�Fe and Mn; m-dobdc4?�= 4,6-dioxido-1,3-benzenedicarboxylate) metal-organic frameworks via solvothermal method for the purpose of hydrogen storage application. The X-ray diffraction, transmission electron microscope, scanning electron microscope, energy dispersive X-ray analysis, and nuclear magnetic resonance spectroscopic studies have been done to ensure the synthesized material is M2(m-dobdc) (M�=�Fe and Mn) MOFs. The Brunauer-Emmett-Teller (BET) analysis reveals the average pore size of 36.271 nm for Mn2(m-dobdc) MOF whereas the average pore size for fe2(m-dobdc) MOF was found to be 2.1992 nm. The as-prepared MOF samples are in the mesoporous range based on pore size distribution (internal pore diameter greater than 2�nm) with spherical pore geometry. Hydrogen storage studies shows that Fe2(m-dobdc) has a hydrogen storage capacity of 0.18 wt% at ambient temperature (30�C) under 100 atm H2 pressure, whereas the hydrogen storage capacity for Mn2(m-dobdc) is 1.38 wt% under identical conditions of temperature and pressure. The hydrogen storage capacity at liquid nitrogen temperature (?196�C) under 100 atm H2 pressure for Fe2(m-dobdc) and Mn2(m-dobdc) is 4.31 and 8.21 wt%, respectively. � 2022 John Wiley & Sons Ltd.Publication Isolation and functional characterization of a fungal plant symbiont Nigrospora sphaerica, associated to Euphorbia hirta L.(Springer, 2022) Gautam, Veer Singh; Nishad, Jay Hind; Kumari, Puja; Singh, Arti; Verma, Satish Kumar; Sharma, Vijay Kumar; Kumar, Jitendra; Kharwar, Ravindra NathThe endophytic fungi are the endosymbiont which play important role in improving host plant fitness and source of plethora of bioactive molecules. Present study includes the assessment of antimicrobial activity, phytochemical analysis and enzymes activity of fungal endophyte EHL2, isolated from leaf tissues of an Indian medicinal plant Euphorbia hirta L. The fungus exhibited the antibacterial and antifungal activities against a broad range of bacterial and fungal pathogens. To the best of our knowledge, this is the first report about the isolation and characterization of endophytic fungus�Nigrospora sphaerica (EHL2) recovered from�E. hirta L. The minimum inhibitory concentration (MIC) of the crude extract against pathogenic bacteria ranged from 0.45 to 3.14�mg/ml. For antifungal ativity of fungus, the highest percentage of inhibition was observed against Colletotrichum sp. (33.78%) while, minimum activity was noticed against Alternaria solani (16.60%). Preliminary mycochemical analysis revealed the positive tests for alkaloids, phenolics, flavonoids and terpenoids. The results showed that the total phenolic content (TPC) and total flavonoid content (TFC) of crude extracts were 78.11 � 0.04�mg GAE/g and 235.94 � 3.06�mg RE/g, respectively. Furthermore, the fungus also produced amylase, cellulase, protease and laccase enzymes. In conclusion, these positive results of mycochemicals and enzymes activity displayed by N. sphaerica of E. hirta provide an opportunity which could be exploited for host protection against pathogens and enzyme production. � 2022, Indian Phytopathological Society.Publication Mechanistic understanding of the superior catalytic effect of Al65Cu20Fe15 quasicrystal on de/re-hydrogenation of NaAlH4(Elsevier Ltd, 2023) Verma, Satish Kumar; Bhatnagar, Ashish; Shaz, Mohammad Abu; Yadav, Thakur PrasadThe complex hydride NaAlH4 remains the archetype hydrogen storage system. In this paper, we have explored the catalytic action of Al65Cu20Fe15 quasicrystal (QC) on the de/re-hydrogenation study of NaAlH4. The leached ball-milled Al65Cu20Fe15 (LBMACF) catalyzed NaAlH4 sample has shown a lower hydrogen desorption temperature (140 �C) than other catalyzed and uncatalyzed NaAlH4 samples. NaAlH4-LBMACF rapidly absorbed ?3.20 wt% of hydrogen within 1 min and absorbed maximum capacity (?4.68 wt%) in 15 min, while NaAlH4-LACF, NaAlH4-BMACF, NaAlH4-ACF, and pristine NaAlH4 absorbed only 0.50 wt%, 1.38 wt%, 1.10 wt%, and 0.70 wt% in 1 min at 130 �C under 100 atm hydrogen pressure. NaAlH4-LBMACF has desorbed ?4.22 wt% of hydrogen within 15 min, while the same amount of hydrogen desorbed by NaAlH4-LACF takes 45 min at 130 �C under 1 atm hydrogen pressure. NaAlH4-LBMACF shows reversibility up to 25 cycles with minimum degradation of hydrogen storage capacity of ?0.06 wt% during de/re-hydrogenation. The catalytic mechanism and catalytic effect of Al�Cu�Fe on the NaAlH4 have been discussed using structural, microstructural analysis, in-situ nuclear magnetic resonance (NMR) spectroscopy, in-situ Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). � 2022 Hydrogen Energy Publications LLCPublication Microbial biofilm in remediation of environmental contaminants from wastewater: Mechanisms, opportunities, challenges, and future perspectives(CRC Press, 2022) Singh, Pallavi; Maheshwari, Akshita; Dharmesh, Varsha; Anand, Vandana; Kaur, Jasvinder; Srivastava, Sonal; Verma, Satish Kumar; Srivastava, Suchi[No abstract available]Publication Seed inhabiting bacterial endophytes of maize promote seedling establishment and provide protection against fungal disease(Elsevier GmbH, 2022) Pal, Gaurav; Kumar, Kanchan; Verma, Anand; Verma, Satish KumarBacteria from different crops and plant varieties have been shown to possess enormous growth promotional attributes. The study aimed to investigate the role of the endophytic microbiome of seeds of corn in improving the growth of seedlings of two different varieties of maize crops (K-25 and baby corn). Furthermore, the study also assessed the role of these bacteria in the protection of seedlings from fungal pathogens. Total twenty-three endophytic bacterial strains were isolated from maize seeds and identified using 16S rDNA sequencing. Most of the isolates had the ability to synthesize auxin (70 %) and solubilize phosphate (74 %), while all the isolates showed nitrogen fixation ability. Some isolates also showed antagonistic activity against phytopathogenic fungi including Rhizoctonia solani and Fusarium sp. suggesting their biocontrol potential. The presence of different lipopeptide genes including bacillomycin D, fengycin, iturin A and surfactin was confirmed in some of the isolates. We observed that treating seeds with an antibiotic compromised the seedlings� growth; however, re-inoculation with endophytic isolates (ZM1/Lysinibacillus sp. and ZM2/Paenibacillus dendritiformis) restored the growth of the seedlings in terms of improved root and shoot development in comparison to non-inoculated controls. The colonization of inoculated bacteria on the root surface was visualized using fluorescent microscopy. Seedling protection assay showed that treated seeds (with ZMW8/ Bacillus velezensis) were protected from fungal infestation (Fusarium verticillioides) even after 12 days of inoculation in comparison to the uninoculated control. The study concludes that indigenous seed-associated bacteria of maize play a major role during seed germination, seedling formation and protect them from phytopathogens. � 2021 Elsevier GmbHPublication STUDIES ON HYDROGEN STORAGE PERFORMANCE OF CATALYZED MgH2(International Association for Hydrogen Energy, IAHE, 2022) Verma, Satish Kumar; Shaz, Mohammad Abu; Yadav, Thakur PrasadMgH2 is the widely investigated and one of the most prominent solid state hydrogen storage materials because of its high hydrogen storage capacity, low cost, and enormous elemental reserves in the earth crust and seawater. However, the high desorption temperature, sluggish kinetics and high thermal stability hinder its further onboard application. In present investigation, we have reported the enhanced kinetics and thermodynamics for MgH2 catalyzed through different prominent catalysts/additives like graphene (Gr), VS2, TiH2@Gr, Ti@Gr, TiO2@Gr, and high entropy alloy (HEA). Amongst these catalysts TiH2@Gr is most suitable catalyst for empowering the kinetics and thermodynamics of MgH2. The temperature programmed study reflects that MgH2-TiH2@Gr has lowest onset desorption temperature i.e., ~231 oC with a storage capacity ~6.55 wt% which is ~190 oC lower than the desorption temperature of pristine MgH2. The better catalytic behavior of MgH2-HEA on TiH2@Gr also persists during de/rehydrogenation kinetics of MgH2. Thus, MgH2 catalyzed by HEA absorbs ~5.9 wt% of hydrogen at 300 oC under 15 atm pressures in 1.5 min. A remarkable result coming out of the present investigation is concerning cyclability (reversibility) of MgH2-HEA, up to 25 cycles. � 2022 Proceedings of WHEC 2022 - 23rd World Hydrogen Energy Conference: Bridging Continents by H2. All rights reserved.Publication Waste and biomass-based nanomaterials for CO2 capture(Elsevier, 2022) Verma, Satish Kumar; Prajapati, Abhimanyu Kumar; Tripathi, Manoj; Bhatnagar, AshishThe world�s countries emit vastly different amounts of heat-trapping gases (greenhouse gases) into the atmosphere. Human activities such as burning fossil fuels for electricity, heat, and transportation are responsible for the increase in greenhouse gases in the atmosphere over the last 150 years. CO2 emissions also result from some industrial and resource extraction processes and the burning of forests during land clearance. In 2020, the top carbon dioxide (CO2) emitters were China, the United States, the European Union, India, the Russian Federation, and Japan. These data include CO2 emissions from fossil fuel combustion, as well as cement manufacturing and gas flaring. Together, these sources represent a large proportion of total global CO2 emissions. The imbalance in atmospheric CO2 concentration caused by emissions from various anthropogenic sources has led to variations in climate across the globe. It has created an urgent demand for developing methods and materials to capture and store CO2 in a cost-effective and environment-friendly way. Many research groups have addressed these issues by continuously finding suitable strategies and developing new methods/materials that will potentially minimize CO2 emissions and eventually contribute to a healthy and sustainable future for the planet. The CO2 capturing requires the use of unique materials that possess inherent superior textural and surface properties or have been suitably functionalized to develop high adsorption capacities. Decades of research have indicated that different materials like activated carbon, metal-organic framework, aerogels, biomass-based nanomaterials (porous carbon), etc., fulfill the required texture and surface properties needed for CO2 capture and can be used as absorbents for CO2. � 2023 Elsevier Inc. All rights reserved.
