Browsing by Author "Kumar, Manish"

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Co-transport and deposition of fluoride using rice husk-derived biochar in saturated porous media: Effect of solution chemistry and surface properties
(Elsevier B.V., 2023-02-10T00:00:00) Kumar, Rakesh; Sharma, Prabhakar; Rose, Pawan Kumar; Sahoo, Prafulla Kumar; Bhattacharya, Prosun; Pandey, Ashok; Kumar, Manish
Fluoride (F?) contamination in water is a global health concern, threatening the well-being of millions. This study investigated the role of ZnCl2/FeCl3-rice husk-modified biochar (Zn-BC and Zn/Fe-BC) in treating F?-contaminated surface and groundwater under the influence of varying solution chemistry, co-existing ions, and biochar-amended through column transport experiments. Modified biochar showed maximum F? adsorption, 99.01% and 91.90% using Zn/Fe-BC and Zn-BC, respectively, than 85.87% using raw biochar (R-BC). Raw/modified biochars were characterized with FESEM-EDAX, FTIR, XRD, particle size, surface area, electro-kinetic potential, and point of zero charge analyses. Langmuir and pseudo-second-order kinetic could explain that F?-biochar interactions are dominated by chemisorption at ambient temperature while physisorption at higher temperatures. The influence of salt concentrations and co-occurring ions reduced F? sorption using Zn/Fe-BC. Increased salt strengths led to reduced electrophoretic mobility of biochar particles, i.e., biochar�biochar particles attract each other and increase the hydrodynamic diameter, which ultimately reduces the active sites on biochar for F? adsorption. Co-transport and deposition of biochar and F? in saturated porous media revealed lower mobility of biochar, and maximum F? adsorption was observed at 10 mM salt strength. Biochar transport is governed by electrostatic interactions, whereas F? transport mainly occurs through chemisorption. In rural areas, hand pumps and tube wells are generally used as source of potable water for drinking and cooking purposes; thus, biochar-mediated sand columns can be utilized for defluoridation. Thus, Zn/Fe-BC can be utilized as a potential bio-adsorbent for F?-contaminated natural surface and groundwater with optimum preparation and treatment costs. � 2023 The Authors
Geochronology and oxygen fugacity of the pelitic granulite from the Diwani hills, NE Gujarat (NW India)
(Cambridge University Press, 2022-08-01T00:00:00) Kumar, Manish; Prakash, D.; Singh, C.K.; Yadav, M.K.; Tewari, S.; Singh, Pradip K.; Mahanta, B.
The Diwani hills are located SE of Balaram-Abu Road in the Banaskantha district of north Gujarat. The crystalline rocks of the Diwani hill area are a diverse assemblage of Precambrian metamorphic and igneous rocks. These rocks are petrologically more complex and date back to the Aravallis or earlier. The mineralogical assemblages such as grt-sp-opx-qz of these rocks indicate their origin in anhydrous or dry conditions, implying metamorphism under pyroxene granulite facies. These granulitic rocks were subjected to Delhi orogenic deformation and were later intruded by the Erinpura granite. Textural and microstructural relationships, mineral chemistry, P-T-X pseudosection modelling and the oxidation state of pelitic granulites from the Diwani hill area of north Gujarat are all part of the current approach. The winTWQ program and pseudosection modelling in the NCKFMASHTO model system utilizing Perple_X software were used to restrict the P-T evolution of these pelitic granulites. The unification of these estimates shows that the pelitic granulites reached their pressure and temperature maxima at 8.6 kbar and 770 �C, respectively. The oxygen fugacity (log fO2) versus temperature computations at 6.2 kbar revealed log fO2-T values of -13.0 and 765 �C, respectively. The electron microprobe dating of monazite grains separated from the granulites of the Diwani hills yields ages ranging from 769 Ma to 855 Ma. The electron microprobe dating presented here from the Diwani hills provides evidence for a Neoproterozoic (Tonian) metamorphic event in the Aravalli-Delhi Mobile Belt. � The Author(s), 2022. Published by Cambridge University Press.
The Post-Cold War Global Politics: A Study of India's Role in Nonaligned Movement
(Central University of Punjab, 2018) Kumar, Manish; Verma, Sudheer Singh
The post-Second World War confrontational bipolarity enforced infant decolonised nations to adopt the policy of nonalignment to preserve their hard won sovereignty. India as pioneer nation introduced the notion of nonalignment and contributed to the development of Nonaligned Movement through prolonged collective deliberations with Asian and African countries for global peace and equitable global order. Using Nonaligned Movement's platform, India significantly gained her security, national development, and world order interests but loses some strategic interests during the war with China in 1962. However, being non-aligned, India has constructed enough capacity to cope further security challenges through building strategic alliances with suitable powers. India being a frequent participant country in periodical summits of Nonaligned Movement has committed to its principles and objectives. The end of the Cold War had posed several questions over its enduring existence in the global politics. The post-Cold War unipolarity has made Nonaligned Movement increasingly "responder" rather 'demander'. India's increased economic, military and political weight in global politics in the 21st century, realised New Delhi to calculate the potentials of Nonaligned Movement in accordance with its aspiration of great power status. In this context, by all reckoning, India is likely to be crediting the third world solidarity, nonetheless passionate for multialignment with major powers to gain its commensurate office in global governance.
Rice husk biochar - A novel engineered bio-based material for transforming groundwater-mediated fluoride cycling in natural environments
(Academic Press, 2023-05-24T00:00:00) Kumar, Rakesh; Sharma, Prabhakar; Sharma, Pushpa Kumari; Rose, Pawan Kumar; Singh, Rakesh Kumar; Kumar, Nishant; Sahoo, Prafulla Kumar; Maity, Jyoti Prakash; Ghosh, Ashok; Kumar, Manish; Bhattacharya, Prosun; Pandey, Ashok
Biochar, a promising carbon-rich and carbon-negative material, can control water pollution, harness the synergy of sustainable development goals, and achieve circular economy. This study examined the performance feasibility of treating fluoride-contaminated surface and groundwater using raw and modified biochar synthesized from agricultural waste rice husk as problem-fixing renewable carbon-neutral material. Physicochemical characterizations of raw/modified biochars were investigated using FESEM-EDAX, FTIR, XRD, BET, CHSN, VSM, pHpzc, Zeta potential, and particle size analysis were analyzed to identify the surface morphology, functional groups, structural, and electrokinetic behavior. In fluoride (F?) cycling, performance feasibility was tested at various governing factors, contact time (0�120 min), initial F? levels (10�50 mg L?1), biochar dose (0.1�0.5 g L?1), pH (2�9), salt strengths (0�50 mM), temperatures (301�328 K), and various co-occurring ions. Results revealed that activated magnetic biochar (AMB) possessed higher adsorption capacity than raw biochar (RB) and activated biochar (AB) at pH 7. The results indicated that maximum F? removal (98.13%) was achieved using AMB at pH 7 for 10 mg L?1. Electrostatic attraction, ion exchange, pore fillings, and surface complexation govern F? removal mechanisms. Pseudo-second-order and Freundlich were the best fit kinetic and isotherm for F? sorption, respectively. Increased biochar dose drives an increase in active sites due to F? level gradient and mass transfer between biochar-fluoride interactions, which reported maximum mass transfer for AMB than RB and AB. Fluoride adsorption using AMB could be described through chemisorption processes at room temperature (301 K), though endothermic sorption follows the physisorption process. Fluoride removal efficiency reduced, from 67.70% to 53.23%, with increased salt concentrations from 0 to 50 mM NaCl solutions, respectively, due to increased hydrodynamic diameter. Biochar was used to treat natural fluoride-contaminated surface and groundwater in real-world problem-solving measures, showed removal efficiency of 91.20% and 95.61%, respectively, for 10 mg L?1 F? contamination, and has been performed multiple times after systematic adsorption-desorption experiments. Lastly, techno-economic analysis was analyzed for biochar synthesis and F? treatment performance costs. Overall, our results revealed worth output and concluded with recommendations for future research on F? adsorption using biochar. � 2023 Elsevier Ltd
X-ray fluorescence: Current trends and future scope
(wiley, 2022-04-15T00:00:00) Sindhu, Rakesh K.; Yadav, Shantanu K.; Kaur, Arashmeet; Kumar, Manish; Kumar, Pradeep
X-ray fluorescence is a non-destructive research technique, which is used to assess a material's chemical composition. Many early X-ray fluorescence imaging (XFI) research projects in live systems have used plants. Early XFI studies allowed plants to be impervious to radiation harm from the X-ray beam, although the plants are interesting themselves, and so can often be seen in working order. Metal forming nanoparticles and clusters are important scaffolds in the evolving nanomedical sector in therapeutic as well as diagnostic applications. Fluorescent metal ion specimens are molecules which are precisely manufactured for the interaction of metal ions with a certain level of discernment. This method has significant advantages, with the comfort of optical microscopy as well as the speed with which a pictured can be obtained. FTIR Spectroscopy offers rich and non-destructive biologic data for the use of a suitable substrate and can be achieved on the same model as XFI tests. � 2022 John Wiley & Sons Ltd. All rights reserved.