Browsing by Author "Kamlesh Kumar"

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An improved class of estimators for population mean using auxiliary character in the presence of non-response
(2012) B.B. Khare; U. Srivastava; Kamlesh Kumar
An improved class of estimators for population mean using one auxiliary character in the presence of nonresponse has been suggested and its properties are studied for the fixed sample sizes (n', n), for the fixed cost and for the specified precision. The proposed class of estimators is found to be more efficient than the relevant estimators for the fixed sample sizes (n', n) and for the fixed cost C ≤ C0, which is supported with the help of an empirical study. The proposed class of estimators is also having less cost than the cost incurred in the relevant estimators for the specified precision which is also supported by empirical study. © The National Academy of Sciences, India 2012.
Axial ligand-induced high electrocatalytic hydrogen evolution activity of molecular cobaloximes in homo- and heterogeneous medium
(Royal Society of Chemistry, 2024) Jitendra Kumar Yadav; Baghendra Singh; Anjali Mishra; Sarvesh Kumar Pal; Nanhai Singh; Prem Lama; Arindam Indra; Kamlesh Kumar
Three new molecular cobaloxime complexes with the general formula [ClCo(dpgH)2L] (1-3), where L1 = N-(4-pyridylmethyl)-1,8-naphthalimide, L2 = 4-bromo-N-(4-pyridylmethyl)-1,8-naphthalimide, L3 = 4-piperidin-N-(4-pyridylmethyl)-1,8-naphthalimide, have been synthesized and characterized by UV-Vis, multinuclear NMR, FT-IR and PXRD spectroscopic techniques. The crystal structures of all complexes have also been reported. The electrocatalytic activity of complexes is investigated under two catalysis conditions: (i) homogeneous conditions in acetonitrile using acetic acid (AcOH) as a proton source and (ii) heterogeneous conditions upon immobilization onto the surface of activated carbon cloth (CC). Complex 3 exhibited high electrocatalytic HER activity under both homogeneous and heterogeneous conditions. It catalyses proton reduction to molecular hydrogen in acetonitrile solution at a lower overpotential (640 mV) with a high turnover frequency (TOF) of 524.57 s−1 and demonstrates good stability in acidic conditions. Furthermore, catalytic (working) electrodes are prepared by immobilizing the complexes onto the surface of activated carbon cloth (CC) for electrocatalytic HER under heterogeneous conditions. An impressive HER performance was again obtained with catalytic electrode 3@CC in 1.0 M KOH, achieving a current density of −10 mA cm−2 at an overpotential of 262 mV. Chronoamperometric (CA) studies showed no significant decay of the initial current density for 10 h, indicating the excellent stability of 3@CC. Additionally, UV-Vis and NMR spectral studies of the recovered catalyst after electrocatalysis revealed no structural changes, demonstrating its robustness under reaction conditions. © 2024 The Royal Society of Chemistry.
Boosting photocatalytic hydrogen generation by the combination of tunable cobaloxime and covalent organic framework
(Elsevier Ltd, 2022) Dnyaneshwar Aand; Saddam Sk; Kamlesh Kumar; Ujjwal Pal; Ajay K. Singh
Here, we have investigated the photocatalytic activities of substituted Schiff-based COFs as photosensitizes and molecular cobaloximes as non-noble metal co-catalysts for the hydrogen production from water under visible light irradiation. The steric and electronic properties of the functional group at the backbone of COFs, and cobaloximes, have a pronounced effect on the photocatalytic performance of the photocatalytic system. We established that the methyl-substituted COF (COF-AD1) as a photosensitizer, chloro (p-N,N-dimethylpyridine) cobaloxime (Co-2) as co-catalyst and triethanolamine (TEOA) sacrificial electron donor form a highly active photocatalytic system which exhibited a record hydrogen production rate of 7072 μmolg−1h−1 with a quantum efficiency of 51.4%, TOF of 35.6, TON of 462.4 for 20 h in a 4:1 acetonitrile/water mixture. © 2021 Hydrogen Energy Publications LLC
Chlorocobaloxime containing N-(4-pyridylmethyl)-1,8-naphthalamide peripheral ligands: synthesis, characterization and enhanced electrochemical hydrogen evolution in alkaline medium
(Royal Society of Chemistry, 2022) Jitendra Kumar Yadav; Baghendra Singh; Sarvesh Kumar Pal; Nanhai Singh; Prem Lama; Arindam Indra; Kamlesh Kumar
Two new discrete cobaloxime based complexes with the general formula [ClCo(dioxime)2L] (1 and 2), L1 = N-(4-pyridylmethyl)-1,8-naphthalamide, L2 = 4-bromo-N-(4-pyridylmethyl)-1,8-naphthalamide have been synthesized and characterized by various spectroscopic techniques such as FT-IR, 1H, 13C{1H} NMR and PXRD. The molecular structures of both complexes have also been determined using single crystal X-ray crystallography. The solid state molecular structures revealed distorted octahedral geometry around the Co(iii) central metal ion with two dioximes in the equatorial plane and axial positions are occupied by chloro and pyridine nitrogen of N-(4-pyridylmethyl)-1,8-naphthalamide ligands. Both complexes exhibit weaker non-covalent interactions (C-H⋯O, C-H⋯Cl and C-H⋯π(Centroid) in complex 1 whereas C-H⋯O and C-H⋯Br in complex 2) resulting in the formation of dimeric and 1D supramolecular structures. Furthermore, these complexes are immobilized onto the surface of activated carbon cloth (CC) and their electrocatalytic performance for the hydrogen evolution reaction (HER) has been investigated in alkaline and acidic media as well as buffer solution. In alkaline medium, we found that complex 2 exhibited impressive electrocatalytic HER activity and produced a current density of −10 mA cm−2 at an overpotential of 260 mV, whereas complex 1 produced the same current density at an overpotential of 334 mV. An electrochemical impedance spectroscopy (EIS) spectral study revealed the faster charge transfer kinetics of complex 2 than that of complex 1. Similarly, the low Tafel slope (100 mV dec−1) for the HER with complex 2 indicates faster HER kinetics compared to complex 1. The chronoamperometric study showed that complex 2 is stable under electrocatalytic HER conditions for 5 h without losing the initial current density and it has also been established that the complex structure is retained after electrocatalysis. © 2023 The Royal Society of Chemistry.
COUPLED ROLE OF CLIMATE AND TECTONICS IN THE DEPOSITION OF THE LATE QUATERNARY SEDIMENTARY SEQUENCE IN THE SOUTHERN MARGIN OF THE CENTRAL GANGA PLAIN, INDIA
(SEPM Society for Sedimentary Geology, 2024) Mukesh Yadav; U.K. Shukla; G.P. Gurumurthy; Sajid Ali; Kamlesh Kumar; Anupam Sharma
The Ganga Plain’s sedimentation is primarily controlled by Himalayan tectonics, variations in monsoon intensity, and glacier size. However, the significance of intrabasinal tectonics, which is an interplay of the Himalaya tectonics and basement tectonic configuration of the Ganga Plain, in comprehending the late Quaternary Ganga Plain sedimentation remains unclear. In this study, the sediment provenance and extent of weathering experienced by the sediments are studied using the mineralogical and geochemical (major, trace, and rare earth elements) composition of a sedimentary cliff sequence exposed at the Ramnagar locality near the cratonic peripheral bulge in the southern Ganga Plain. In the Ramnagar cliff sediment section, two sediment packages, designated SP-A and SP-B, are identified based on mineralogy, texture, and geochemistry. These packages of sediments show mild chemical weathering and distinct geochemical compositions. The lower part (SP-A) of the Ramnagar cliff section is characterized by higher contributions from mafic sources (pyroxene, feldspar, and mica as dominant minerals), while the upper part (SP-B) is predominately derived from felsic sources (mica and feldspar as dominant minerals), which are supplied via the peninsular and the Himalayan rivers, respectively. The southern part of the central Ganga Plain shows evidence of a shift in the sediment provenance from mafic to felsic source rock at 40 ka. This study demonstrates how weathering and sedimentation are controlled by both regional tectonics and climate in the southern margin of the central Ganga Plain.; The Director of the BSIP, Lucknow, is thanked by the authors for providing all infrastructural (SAIF) and administrative support to complete the assignment. This work is a part of MY’s doctoral thesis, supported by the funding received from the University Grants Commission (CSIR-UGC JRF fellowship, Roll No. 207693) and recorded as BSIP/RDCC/Publication no. 24/2024-25. The authors also thank Dr. Sheikh Nawaz Ali, Dr. Arvind Kumar Singh, Dr. Naimisha Vanik, Harshita Srivastava, Dr. Masud Kawsar, and Dr. Abhisek Kumar for their constructive suggestions that helped to make the manuscript better. UKS is thankful to the Head of the Department of Geology for providing the working facilities of the Department. We thank editor Dr. Kathleen Marsaglia, Associate Editor Dr. Alberto Resentini, and anonymous reviewers for constructive comments on our manuscript. Ó 2024, SEPM (Society for Sedimentary Geology)
Diagnostic Role of Transvaginal Sonography and Magnetic Resonance Imaging in Adenomyosis of the Uterus and its Correlation with Histopathology
(Wolters Kluwer Medknow Publications, 2023) Shivi Jain; Kamlesh Kumar; Ram Chandra Shukla; Madhu Jain
Background and Objective: The prevalence of adenomyosis of the uterus varies from 5% to 70%, and there is no clear consensus on its imaging diagnostic criteria. The objective of this study was to evaluate the role of transvaginal sonography (TVS), combined TVS and color Doppler (TVS-CD), and magnetic resonance imaging (MRI) in the diagnosis of adenomyosis. Materials and Methods: This was a tertiary care hospital-based prospective study, in which 365 clinically suspected cases of adenomyosis were enrolled. All three types of imaging (TVS, TVS-CD, and MRI) were done in 233/365 patients, followed by hysterectomy in 50. Imaging features were correlated with the histopathological examination (HPE), which was taken as the gold standard for the diagnosis. The diagnostic performance of each imaging modality was assessed. Results: Among patients who underwent hysterectomy, 36/50 (72%) had adenomyosis on HPE, with or without associated benign gynecological abnormalities. Sensitivity, specificity, positive predictive value (PPV), negative PV (NPV), and diagnostic accuracy (DA) of MRI were higher than that of TVS-CD (91.67% vs. 77.78%, 85.71% vs. 78.57%, 94.29% vs. 90.32%, 80% vs. 57.89%, and 90% vs. 78%, respectively). TVS alone had lower diagnostic performance (specificity: 64.29%, PPV 84.85%, NPV 52.94%, and DA74%) than TVS-CD, but equal sensitivity (77.78%). Heterogeneous myometrium was the most sensitive (80.56%), while myometrial cyst was the most specific (92.86%) TVS feature. The maximum junctional zone thickness ≥12 mm was the most sensitive (97.22%), while the hyperintense myometrial focus was the most specific (100%) MRI feature. Conclusion: TVS-CD should be used as an initial diagnostic imaging modality in clinically suspected cases of adenomyosis; however, MRI due to better diagnostic efficacy should be the imaging modality of choice before subjecting such patients to hysterectomy. © 2023 Wolters Kluwer Medknow Publications. All rights reserved.
Effect of Substituents on the Crystal Structures, Optical Properties, and Catalytic Activity of Homoleptic Zn(II) and Cd(II) β-oxodithioester Complexes
(American Chemical Society, 2020) Chote Lal Yadav; Anamika; Gunjan Rajput; Kamlesh Kumar; Michael G. B. Drew; Nanhai Singh
Five novel zinc(II) and cadmium(II) β-oxodithioester complexes, [Zn(L1)2] (1), [Zn(L2)2]n (2), [Zn(L3)2]n (3) [Cd(L1)2]n (4), [Cd(L2)2]n (5), with β-oxodithioester ligands, where L1 = 3-(methylthio)-1-(thiophen-2-yl)-3-thioxoprop-1-en-1-olate, L2 = 3-(methylthio)-1-(pyridin-3-yl)-3-thioxoprop-1-en-1-olate, and L3 = 3-(methylthio)-1-(pyridin-4-yl)-3-thioxoprop-1-en-1-olate, were synthesized and characterized by elemental analysis, IR, UV-vis, and NMR spectroscopy (1H and 13C{1H}). The solid-state structures of all complexes were ascertained by single-crystal X-ray crystallography. The β-oxodithioester ligands are bonded to Zn(II)/Cd(II) metal ions in an OΓS and N chelating/chelating-bridging fashion leading to the formation of 1D (in 2-4) and 2D (in 5) coordination polymeric structures, but complex 1 was obtained as a discrete tetrahedral molecule. Complex 4 crystallizes in the C2 chiral space group and has been studied using circular dichroism (CD) spectroscopy. The multidimensional assemblies in these complexes are stabilized by many important noncovalent C-H···π(ZnOSC3, chelate), π···π, C-H···π, and H···H interactions. The catalytic activities of 1-5 in reactions involving C-C and C-O bond formation have been studied, and the results indicated that complex 3 can be efficiently utilized as a heterogeneous bifunctional catalyst for the Knoevenagel condensation and multicomponent reactions to develop biologically important organic molecules. The luminescent properties of complexes were also studied. Interestingly, zinc complexes 1-3 showed strong lumniscent emission in the solid state, whereas cadmium complexes 4 and 5 exhibited bright luminescent emission in the solution phase. The semiconducting behavior of the complexes was studied by solid-state diffuse reflectance spectra (DRS), which showed optical band gaps in the range of 2.49-2.62 eV. © 2020 American Chemical Society.
Ferrocene-Functionalized Dithiocarbamate Zinc(II) Complexes as Efficient Bifunctional Catalysts for the One-Pot Synthesis of Chromene and Imidazopyrimidine Derivatives via Knoevenagel Condensation Reaction
(American Chemical Society, 2021) Anamika; Chote Lal Yadav; Michael G. B. Drew; Kamlesh Kumar; Nanhai Singh
Four new mononuclear/coordination polymeric (CP) zinc(II) complexes (1-4) of ferrocenyl/pyridyl-functionalized dithiocarbamate ligands, N-ferrocenylmethyl-N-butyl dithiocarbamate (L1), N-ferrocenylmethyl-N-ethylmorpholine dithiocarbamate (L2), N-ferrocenylmethyl-N-2-(diethylamino)ethylamine dithiocarbamate (L3), and N-4-methoxybenzyl-N-3-methylpyridyl dithiocarbamate (L4), have been synthesized and characterized by elemental analyses, IR, UV-vis, and 1H and 13C{1H} NMR spectroscopic techniques. The solid-state structures of complexes 1, 3, and 4 have been determined by single-crystal X-ray crystallography as well as powder X-ray diffraction. Single-crystal X-ray crystallography revealed a monomeric structure for complex 1 but 1D polymeric structures for complexes 3 and 4. In all complexes, dithiocarbamate ligands are bonded to the Zn(II) metal ion in a S^S chelating mode, and in the CPs, N atoms on the 2-(diethylamino)ethylamine and 3-pyridyl functionalities in the ligands on the neighboring molecules are also bonded to metal centers, leading to the formation of either a discrete tetrahedral molecule in 1 or 1D CP structures in 3 and 4. The Zn(II) metal centers in the polymeric structures exhibited either square-pyramidal or octahedral geometries. The supramolecular structures in these complexes are sustained via C-H···π(ZnCS2, chelate; 3 and 4), C-H···π, and H···H interactions. The catalytic performances of complexes have also been assessed in the Knoevenagel condensation and one-pot multicomponent reactions. Catalysis results showed that the CP 3 acts as a heterogeneous bifunctional catalyst with excellent transformation efficiency at low catalyst loading. ©
Functioning of livestock markets and buyers' perspectives on voluntary versus mandatory disclosure of information: Evidence from cattle markets in Uttar Pradesh
(Indian Society of Agricultural Economics, 2014) Rakesh Singh; Tribhuvan Nath; P.K. Singh; Kamlesh Kumar
Using data from buyers and sellers of livestock in three markets in Pratapgarh district of Uttar Pradesh this study examines the functioning of livestock markets with focus on disclosure of information and constraints faced by buyers and sellers. In traditional markets voluntary disclosure has been reported to exist for quite long, but it restricts itself to information on search and experience attributes of the animals which may lead to lack of transparency in the markets. The findings of the study clearly indicate that the livestock market may work well to induce self or voluntary disclosure of information for search and experience attributes, the mandatory disclosure is important for credence attributes of the animal and thereby efficient functioning of markets. The study suggests strengthening of infrastructure in livestock markets.
Generalized chain estimators for the population mean in the presence of non-response
(2011) B.B. Khare; U. Srivastava; Kamlesh Kumar
In this paper, we have proposed two generalized chain estimators for population mean using main and additional auxiliary characters in the presence of non-response and their properties are studied. The proposed estimators have been found to be more efficient than the relevant estimators for fixed values of n' and n, and for fixed cost C
Generalized chain ratio in regression estimators for population mean in the presence of non-response
(University of Salento, 2015) B.B. Khare; Kamlesh Kumar; U. Srivastava
Two generalized chain ratio in regression estimators for population mean using two auxiliary characters in the presence of non-response have been proposed and their properties have been studied. Relative efficiency of the proposed estimators are obtained in the case of fixed first phase sample, second phase sample and sub-sample fraction and also in the case of the fixed cost. Comparison of the proposed estimators has been carried out with the relevant estimators. Expected cost is also obtained in the case of the specified variance. The performance of the proposed estimators in comparison to the relevant estimators has been made with the help of empirical study. © Università del Salento.
Homoleptic Ni(ii) dithiocarbamate complexes as pre-catalysts for the electrocatalytic oxygen evolution reaction
(Royal Society of Chemistry, 2022) Sarvesh Kumar Pal; Baghendra Singh; Jitendra Kumar Yadav; Chote Lal Yadav; Michael G. B. Drew; Nanhai Singh; Arindam Indra; Kamlesh Kumar
Four new functionalized Ni(ii) dithiocarbamate complexes of the formula [Ni(Lx)2] (1-4) (L1 = N-methylthiophene-N-3-pyridylmethyl dithiocarbamate, L2 = N-methylthiophene-N-4-pyridylmethyl dithiocarbamate, L3 = N-benzyl-N-3-pyridylmethyl dithiocarbamate, and L4 = N-benzyl-N-4-pyridylmethyl dithiocarbamate) have been synthesized and characterized by IR, UV-vis, and 1H and 13C{1H} NMR spectroscopic techniques. The solid-state structure of complex 1 has also been determined by single crystal X-ray crystallography. Single crystal X-ray analysis revealed a monomeric centrosymmetric structure for complex 1 in which two dithiocarbamate ligands are bonded to the Ni(ii) metal ion in a S^S chelating mode resulting in a square planar geometry around the nickel center. These complexes are immobilized on activated carbon cloth (CC) and their electrocatalytic performances for the oxygen evolution reaction (OER) have been investigated in aqueous alkaline solution. All the complexes act as pre-catalysts for the OER and undergo electrochemical anodic activation to form Ni(O)OH active catalysts. Spectroscopic and electrochemical characterization revealed the existence of the interface of molecular complex/Ni(O)OH, which acts as the real catalyst for the OER. The active catalyst obtained from complex 2 showed the best OER activity achieving 10 mA cm−2 current density at an overpotential of 330 mV in 1.0 M aqueous KOH solution. © 2022 The Royal Society of Chemistry.
Isonicotinate-Zn(ii)/Cd(ii) bridged dicobaloximes: synthesis, characterization and electrocatalytic proton reduction studies
(Royal Society of Chemistry, 2023) Jitendra Kumar Yadav; Anjali Mishra; Gaurav Kumar Mishra; Sarvesh Kumar Pal; Kedar Umakant Narvekar; Ahibur Rahaman; Nanhai Singh; Prem Lama; Kamlesh Kumar
Herein, we present the synthesis of two new dicobaloxime complexes, [{ClCo(dmgH)2(4-PyCOO)}2Zn(DMF)2] (1) and [{ClCo(dmgH)2(4-PyCOO)}2Cd(H2O)3(DMF)].4H2O (2) bridged by isonicotinate-Zn(ii) and Cd(ii) moieties. These complexes were synthesized upon reaction of a monomeric chlorocobaloxime [ClCo(dmgH)2(4-PyCOOH)] with Zn(NO3)2·6H2O and Cd(OAc)2·2H2O in a methanol/DMF solvent mixture. Both complexes are fully characterized by UV-Visible, FT-IR, and NMR (1H and 13C{1H}) spectral studies. The solid-state structures are also determined by single-crystal X-ray crystallography. In complex 1, Zn (ii) metal ions reside within a four coordinated distorted tetrahedral geometry (ZnO4) formed by two oxygen atoms of isonicotinate connected to cobaloxime units and two oxygen atoms of DMF molecules. In complex 2, the Cd(ii) metal ion exhibited distorted octahedral geometry (CdO6), with two oxygen atoms of isonicotinate that connect to cobaloxime units, one DMF, and three water molecules. The Co(iii) metal center of cobaloxime units in both complexes 1 and 2 displayed distorted octahedral geometry with two dmgH units in the equatorial plane whereas chloride ion (Cl−) and the nitrogen atom of isonicotinate occupy the axial coordination sites. The redox behaviour of both complexes was studied by cyclic voltammetry at variable scan rates in deoxygenated DMF/H2O (95 : 5) solution using 0.1 M TBAPF6 as the supporting electrolyte and a glassy carbon (GC) electrode as the working electrode. Both complexes exhibited similar redox properties and two redox couples CoIII/II and CoII/CoI are observed in the reductive scan. Furthermore, complexes are investigated as electrocatalysts for proton reduction in the presence of acetic acid (AcOH) and complex 1 exhibited impressive electrocatalytic activity compared to complex 2 and monomer. The stability study indicated the retention of molecular structural integrity during HER electrocatalytic experiments. © 2023 The Royal Society of Chemistry.
Legendre collocation method for new generalized fractional advection-diffusion equation
(Taylor and Francis Ltd., 2024) Sandeep Kumar; Kamlesh Kumar; Rajesh K. Pandey; Yufeng Xu
In this paper, the numerical method for solving a class of generalized fractional advection-diffusion equation (GFADE) is considered. The fractional derivative involving scale and weight factors is imposed for the temporal derivative and is analogous to the Caputo fractional derivative following an integration-after-differentiation composition. It covers many popular fractional derivatives by fixing different weights (Formula presented.) and scale functions (Formula presented.) inside. The numerical solution of such GFADE is derived via a collocation method, where conventional Legendre polynomials are implemented. Convergence and error analysis of polynomial expansions are studied theoretically. Numerical examples are considered with different boundary conditions to confirm the theoretical findings. By comparing the above examples with those from existing literature, we find that our proposed numerical method is simple, stable and easy to implement. © 2024 Informa UK Limited, trading as Taylor & Francis Group.
Metal Nanocomposite Synthesis and Its Application in Electrochemical CO2 Reduction
(Springer Nature, 2022) Rishabh Sharma; Pradip Kalbar; Simant Kumar Srivastav; Kamlesh Kumar; Swatantra P. Singh
To address the immoderate emission of carbon dioxide (CO2), the development of earth-excessive metals and non-metals based electrocatalyst is of great importance. The development of an active electrocatalyst with cost-effective, efficient, and easy accessibility for electrochemical-based CO2 reduction (ECR), is a growing field of research. Growing industries and urban populations lead to increased pollution generation, especially air pollution causing serious environmental and health problems and causing deterioration of air quality. Non-conventional energy-based ECR to alternative substitutes with heavy energy densities proves to be an effective route for production and storage of energy and manage the carbon and energy balance. For an efficient yield of chosen products, the modification, outline, technology, and finding of new catalysts are important steps. In the present chapter, we have discussed heterostructures of catalysts, the tunable component for an effective CO2 conversion, and metal/metal oxide hybrids for enhancing CO2 reduction capability, and an alliance between different nanocomposites for efficient reduction processes. The accurate and precise tuning of interlinkage between dissimilar metal and metal oxides will enhance the reaction kinetics, maximize binding between intermediates, and accomplish effective ECR. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
Metal Nanocomposites for Energy and Environmental Applications
(Springer Nature, 2022) Swatantra P. Singh; Simant Kumar Srivastav; Kamlesh Kumar; Avinash Kumar Agarwal
In recent years, metal nanocomposites have shown their potentials for energy and environmental applications. The unsustainable growth of the world economy leading to air, water, and soil pollution. Additionally, high energy demand for economic growth is essential. This book focused on some recent development of metal nanomaterials and nanocomposites for energy and environmental application such as pollution control in water, air, and soil pollution, carbon capture and storage (CCS), and sensing applications. The chapters have been incorporated carbon-based, metal-based and metal–organic framework-based nanomaterials and nanocomposites for emerging contaminants (pharmaceuticals and microplastics) and other traditional pollutants remediation along with energy storage, sensing of air and water polutents and CCS. We hope that the book would be of great interest to the professionals, post-graduate students involved in energy and environmental science and engineering research. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
Metal Organic Frameworks Based Nanomaterial: Synthesis and Applications; Removal of Heavy Metal Ions from Waste Water
(Springer Nature, 2022) Ravindra Singh; Rama Kanwar Khangarot; Ajay Kumar Singh; Kamlesh Kumar
Heavy metals in the water are a global environmental issue. Heavy metals in the wastewater are increasing day by day which is mainly caused by various industrial effluents. Heavy metal ions including, Cadmium (II), Arsenic (III and V), Chromium (III and VI), Copper (II), Lead (II), and Mercury (II) are accumulated readily in the environment. It has been created a lot of serious problem to the human health. Thus, removal of heavy metals from the wastewater is one of the major challenges for the scientific community. Various techniques and materials have been developed for removal of heavy metals from the waste water. Recently, Metal organic frameworks (MOFs) based nanomaterial has been synthesized and used for removal of heavy metal ions from waste water. Electrochemical, photochemical energy conversion and storage, biomedical imaging, drug delivery and catalysis, have been investigated. Its unique characteristic properties are accountable for the waste water treatment like easily synthesizable, various size cavities with different-different functional group, surface functional groups, various functionality where host–guest interaction takes place and high surface area which responsible for high absorption capacity. In this chapter, the attention is given to understand the synthesis, chemistry of MOF based nano-composites and its various applications especially, and removal of heavy metals from waste water has been discussed. It is expected that this chapter can be helpful to understand the synthesis of MOF-based nano-materials and its application towards the elimination of heavy metal ions from waste water. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
Metal Organic Frameworks for Removal of Heavy Metal Cations and Emerging Organic Pollutants
(Springer Nature, 2021) Kamlesh Kumar; Simant Kumar Srivastav; Swatantra P. Singh
The toxicity of wastewater generated from industrial plants is one of the serious environmental issues. The wastewater often contains toxic compounds such as inorganic pollutants (e.g. oxyanions/cations and heavy metal ions) and organic pollutants (e.g. organic dyes, phenols, biphenyls, pesticides, fertilizers, hydrocarbons, plasticizers, detergents, oils, greases, pharmaceuticals, proteins, carbohydrates etc.) which cause severe environmental and health problems. Many organic pollutants are chemically stable and they are not very prone to biodegradable. Hence, their removal from wastewater only by biological processes is challenging. Many physical, chemical and biological techniques have been developed for wastewater treatment and physical adsorption method has been considered the most effective. Thus materials with adsorption properties have gained wide attention in the scientific community. In recent years, metal–organic frameworks (MOFs) have been employed in technologies to bring an inspiring breakthrough for wastewater treatment. The MOF is class of materials with the exceptionally high surface areas and larger porosity, easier in pore structure designing, and structural modifications. This chapter aims to give insight into the latest developments onto the use of MOFs in the removal of inorganic and emerging organic contaminants present in the wastewater. © 2021, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
Microbes-mediated integrated nutrient management for improved rhizo-modulation, pigeonpea productivity, and soil bio-fertility in a semi-arid agro-ecology
(Frontiers Media S.A., 2022) Gaurendra Gupta; Shiva Dhar; Adarsh Kumar; Anil K. Choudhary; Anchal Dass; V.K. Sharma; Livleen Shukla; P.K. Upadhyay; Anup Das; Dinesh Jinger; Sudhir Kumar Rajpoot; Manjanagouda S. Sannagoudar; Amit Kumar; Ingudam Bhupenchandra; Vishal Tyagi; Ekta Joshi; Kamlesh Kumar; Padmanabh Dwivedi; Mahendra Vikram Singh Rajawat
Excessive dependence on chemical fertilizers and ignorance to organic and microbial inputs under intensive cropping systems are the basic components of contemporary agriculture, which evolves several sustainability issues, such as degraded soil health and sub-optimal crop productivity. This scenario urges for integrated nutrient management approaches, such as microbes-mediated integrated plant nutrition for curtailing the high doses as chemical fertilizers. Rationally, experiment has been conducted in pigeonpea at ICAR-IARI, New Delhi, with the aim of identifying the appropriate nutrient management technique involving microbial and organic nutrient sources for improved rhizo-modulation, crop productivity, and soil bio-fertility. The randomized block-designed experiment consisted nine treatments viz. Control, Recommended dose of fertilizers (RDF), RDF+ Microbial inoculants (MI), Vermicompost (VC), Farm Yard Manure (FYM), Leaf Compost (LC), VC + MI, FYM + MI, and LC + MI. Rhizobium spp., Pseudomonas spp., Bacillus spp., and Frateuria aurantia were used as seed-inoculating microbes. The results indicated the significant response of integration following the trend VC + MI > FYM + MI > LC + MI > RDF + MI for various plant shoot-root growth attributes and soil microbial and enzymatic properties. FYM + MI significantly improved the water-stable aggregates (22%), mean weight diameter (1.13 mm), and geometric mean diameter (0.93 mm), soil organic carbon (SOC), SOC stock, and SOC sequestration. The chemical properties viz. available N, P, and K were significantly improved with VC + MI. The study summarizes that FYM + MI could result in better soil physico-chemical and biological properties and shoot-root development; however; VC + MI could improve available nutrients in the soil and may enhance the growth of pigeonpea more effectively. The outcomes of the study are postulated as a viable and alternative solution for excessive chemical fertilizer-based nutrient management and would also promote the microbial consortia and organic manures-based agro-industries. This would add to the goal of sustainable agricultural development by producing quality crop produce, maintaining agro-biodiversity and making the soils fertile and healthy that would be a “gift to the society.” Copyright © 2022 Gupta, Dhar, Kumar, Choudhary, Dass, Sharma, Shukla, Upadhyay, Das, Jinger, Rajpoot, Sannagoudar, Kumar, Bhupenchandra, Tyagi, Joshi, Kumar, Dwivedi and Rajawat.
Monsoon-influenced variations in productivity and lithogenic flux along offshore Saurashtra, NE Arabian Sea during the Holocene and Younger Dryas: A multi-proxy approach
(Elsevier B.V., 2017) Syed Azharuddin; Pawan Govil; A.D. Singh; Ravi Mishra; Shailesh Agrawal; A.K. Tiwari; Kamlesh Kumar
A sediment core from NE Arabian Sea was studied to reveal the variations in shelf environment of western continental margin of India. A multi-proxy analysis based on planktonic foraminifera abundance (PFA), benthic foraminifera abundance (BFA), planktonic-benthic foraminiferal ratio (P/B), CaCO3 percentage (wt%), Oxygen (δ18OG. ruber) and Carbon (δ18OG. ruber) isotopes of foraminifera as well as sediment X-ray studies were carried out on 3.4 m long core SK-240/485 recovered from offshore Saurashtra, NE Arabian Sea. The study aims to understand the monsoon variability in the NE Arabian Sea offshore Saurashtra since the late Pleistocene-Holocene transition and how monsoon climate coupled with sea-level change influenced paleo-productivity pattern. Six AMS radiocarbon dates place the core in the time interval 12–1 Ka. Our study reveals that there have been three periods of major changes in the monsoonal climate, productivity and sea level; viz. 12–8 Ka (Younger Dryas and early Holocene); 8–4 Ka (middle Holocene) and 4–1 Ka (late Holocene). The studied time period was also marked by weakened south west monsoon (SWM) during the cold events such as Younger Dryas (YD), Abrupt Event (AE) centring around 9.8 Ka as well as 8.2 and 4 Ka cold events. The Younger Dryas and early Holocene shows the low sea level stand and less Indus river discharge. Thereafter during middle and late Holocene the monsoon strengthened which resulted in raised sea level and increased Indus river discharge. The proxy records broadly suggest relatively low foraminiferal productivity at the core location during the Younger Dryas and early Holocene. We record a moderate foraminiferal productivity during the middle Holocene between 8 and 4 Ka, which suggest the mesotrophic condition. The foraminiferal productivity however was relatively high since 4 Ka suggesting the eutrophic conditions at the core site. © 2016 Elsevier B.V.