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Porous potassium tantalate-reduced graphene oxide nano cube architecture for high performance hybrid supercapacitors
No full textEnergy storage has always been a major concern in the present-day situation. Advanced energy storage devices are batteries, supercapacitor and solar cells. However, advancements have been noteworthy in the field of high-performance hybrid supercapacitors. On this note, we have fabricated a hybrid supercapacitor electrode material Potassium tantalate nano cube (KT NCs) and its reduced graphene oxide composite (KT-rGO NCs) and tested its electrochemical performance. The materials showed high performances with specific capacitance of 565 F/g for KT NCs and 850 F/g for KT-rGO NCs respectively. Energy densities of both KT NCs & KT-rGO NCs are 28.24 Wh/Kg and 29.50 Wh/kg with good retention capacities. Further detailed study of both KT NCs and KT-rGO NCs are carried out with characterization techniques like XRD, FTIR, BET, Raman and HRTEM for structural analysis and electrochemical measurements to analyse various parameters pertaining to its charge storage capacity
High-Speed Motion Analysis-Based Machine Learning Models for Prediction and Simulation of Flyrock in Surface Mines
No full textBlasting is a cost-efficient and effective technique that utilizes explosive chemical energy to generate the necessary pressure for rock fragmentation in surface mines. However, a significant portion of this energy is dissipated in undesirable outcomes such as flyrock, ground vibration, back-break, etc. Among these, flyrock poses the gravest threat to structures, humans, and equipment. Consequently, the precise estimation of flyrock has garnered substantial attention as a prominent research domain. This research introduces an innovative approach for demarcating the hazardous zone for bench blasting through simulation of flyrock trajectories with probable launch conditions. To accomplish this, production blasts at five distinct surface mines in India were monitored using a high-speed video camera and data related to blast design and flyrock launch circumstances including the launch velocity (vf) were gathered by conducting motion analysis. The dataset was then used to develop ten Bayesian optimized machine learning regression models for predicting vf. Among all the models, the Extremely Randomized Trees Regression model (ERTR-BO) demonstrated the best predictive accuracy. Moreover, Shapely Additive Explanation (SHAP) analysis of the ERTR-BO model unveiled bulk density as the most influential input feature in predicting vf, followed by other features. To apply the model in a real-world setting, a user interface was developed to aid in flyrock trajectory simulation during bench blast designing
Characterization of lignite deposits of Barmer Basin, Rajasthan: insights from mineralogical and elemental analysis
No full textThe geochemistry of fly ash produced from the combustion of coal at thermal power plants presents a significant challenge for disposal and environmental impact due to its complex mineralogical and elemental composition. The objective of this study was to investigate the mineralogical and elemental distribution of thirty lignite samples from the Barmer Basin using advanced techniques such as X-ray diffraction (XRD), X-ray fluorescence spectrometry (XRF) and inductively coupled plasma mass spectrometry (ICP-MS). XRD analysis revealed the presence of minerals such as haematite (Fe2O3), nepheline, anhydrite, magnesite, andalusite, spinel and anatase. Other minor minerals included albite, siderite, periclase, calcite, mayenite, hauyne, pyrite, cristobalite, quartz, nosean and kaolinite. XRF analysis demonstrated that the most abundant elements in the Barmer Basin lignite ash were iron oxide (Fe2O3), sulphur oxide (SO3), calcium oxide (CaO), and quartz (SiO2) followed by minor traces of toxic oxides (SrO, V2O5, NiO, Cr2O3, Co2O3, CuO) that are known to have adverse effects on human health and the environment. The rare earth element (REE) composition showed higher concentrations of Tb, Dy, Ho, Er, Tm, Yb, Lu, Y and Sc at the Giral and lower concentrations at Sonari mine. The Barmer lignites recorded higher concentration of trace elements such as V, Cr, Co, Ni, Cu and Sr while lower concentration of Rb, Cs, Ba, Pb, As, Th and U were observed within optimal range. The study findings revealed the predominant mineral concentration, elemental makeup, trace elements and rare earth elements associated with lignite reserves in the Barmer Basin
Development of fluorescent carbon nanoparticles from Madhuca longifolia flower for the sensitive and selective detection of Cr6+: a collective experimental–computational approach
No full textHerein, blue-emitting carbon nanoparticles (CNPs) were synthesized using the Madhuca longifolia flower for the highly selective and sensitive detection of Cr6+ ions in aqueous media using a simple, green, and cost-effective approach, and computational experiments were also performed. The prepared CNPs were well-dispersed in water with an average diameter of 12 nm and functionalized with carbonyl, hydroxyl and carboxylic acid groups. The decrease in the fluorescence intensity of the CNPs with an increase in the content of Cr6+ provided an important signal for the sensitive and selective detection of Cr6+ in aqueous media. The limit of detection for Cr6+ in an aqueous medium was found to be 103 ppb, which is more sensitive in comparison with the previously reported study. Furthermore, the validation of the proposed higher sensing feature and more selective nature of the CNPs towards Cr6+ was also explained using an in silico approach. The results from the theoretical calculations based on the DFT approach demonstrated that the binding energy (BE) of the CNPs with three transition metal (TM) cations (Cr6+, Fe3+, and Hg2+) follows the order of Cr6+ > Fe3+ > Hg2+, where the Cr6+ TM cation associated with the CNPs possesses the highest valence state, showing the highest sensing feature and highest selectivity among the investigated ions, as expected. The metal ions associated with the CNPs having a higher charge and a smaller radius indicated a higher BE and larger degree of deformation of the CNPs. Moreover, to achieve new insights into the structural, stability/energetics, and electronic features, some useful tools, such as NCI-plot, HOMO–LUMO gap, MESP, and QTAIM analysis were employed, which facilitated noteworthy outcomes
Environmental impact and health risk assessment due to coal mining and utilization
No full textCoal has served as a fundamental pillar of global energy production for centuries, fueling industries, households, and economies. Despite its crucial role in meeting energy demands, the mining and utilization of coal have given rise to grave concerns regarding environmental degradation and public health risks. Coal mining and usage significantly contribute to greenhouse gas emissions and air pollution, leading to global climate change and adverse health effects on both nearby communities and the wider population. The environmental consequences of coal extraction, transportation, and combustion are extensive, affecting ecosystems, water resources, and air quality. Hence, it is essential to conduct a comprehensive and rigorous assessment of these impacts to provide valuable insights to policymakers, industries, and communities, enabling them to adopt effective mitigation strategies. The health implications of coal mining and utilization are considerable and diverse. Exposure to particulate matter, heavy metals, and other harmful pollutants from coal-related activities can result in respiratory diseases, cardiovascular issues, and even long-term chronic health conditions. Vulnerable populations, such as children, the elderly, and socioeconomically disadvantaged communities, often bear a disproportionate burden of these health risks. This Special Issue brings together a wide array of research articles, reviews, and case studies from esteemed researchers and experts in the field. Through sharing their findings, insights, and recommendations, this collaborative effort aims to facilitate meaningful dialogue, inspire impactful actions, and contribute to a more comprehensive understanding of coal’s environmental and health implications. We hope that this collection of research not only raises awareness about the challenges associated with coal mining and utilization but also paves the way for sustainable practices, policies, and technologies that prioritize the health of our planet and its inhabitants.
The Special Issue on “Environmental Impact and Health Risk Assessment Due to Coal Mining and Utilization” contains 26 different research papers from all over the world, including India, China, Republic of Korea, UK, Pakistan, Italy, Romania, Ecuador, Bangladesh, Brazil, Saudi Arabia, Turkey, South Africa, and Malaysia (Fig. 1). These papers focus on five different topics: (1) Geology and Geochemistry of Coal, (2) Coal Mining Areas on Groundwater, (3) Human Health Risk Assessment, (4) Heavy Metal and Trace Elements Pollution, and (5) Emission Due to Coal Combustion. This editorial briefly reviews the papers that focused on various topics related to Environmental Impact and Health Risk Assessment Due to Coal Mining and Utilization
A characteristic-based decision tree approach for sustainable energy applications of biomass residues from two major classes
No full textThe characteristic potential of biomass residues from two major classes for sustainable energy applications has
been critically evaluated. These include sheesham wood dust (SWD), sheesham bark (SB), eucalyptus chips
(ECLP), gamhar wood chips (GWC) from wood and woody biomass (WWB) class; and coconut shell (CS), coconut
husk (CH), rice straw (RS), rice husk (RH), wheat husk (WH), bagasse (BGS), tea waste (TW), corn cob (CC), pista
shell (PS), akhrot shell (AS) and mustard stalk (MS) from herbaceous and agricultural biomass (HAB) class.
Overall, biomass residues cover a wide range of acceptable moisture levels for various thermal conversion
processes. Fixed carbon (FC), C, and H content of all the samples showed linearity with calorific value (CV), but
H/C and O/C atomic ratios, besides linearity with cellulose and hemicellulose, have non-linearity with CV and
lignin. Specifically, agricultural wastes (RS, RH, and WH) have relatively less moisture, volatile matter, FC, C,
and CV; and higher ash, H/C, and O/C atomic ratios, N, and S content. WWBs have higher CV than other residues
(particularly agricultural residues), owing to higher lignin content (with higher heat value) than hemicellulose
and cellulose.
Among various ash components, assigning a clear trend is difficult. BGS, PS, and AS indicate extremely-high
slagging and high fouling tendencies, and the remaining 12 samples have low to medium concerns. Amongst
hemicellulose (H), cellulose (C), lignin (L), and extractives (Ext), four structural types (CLHExt > CHLExt >
HCLExt > LExtHC) exist. CLHExt follows in 3WWB and 2HAB; CHLExt in 8 HAB; HCLExt in 1 HAB; LExtHC in 1
WWB sample. Thermal analysis results show that HABs are mostly more reactive and have less activation energy
than WWBs. The observed experimental findings and characteristic associations form a basis for placing these
feedstocks for indicator purposes linked with further advance and sustainable feedstock processing needed for
gasification, combustion, and steelmaking. A novel decision tree approach has been developed for propositions
about characteristic parameters, which provides a systematic means of selecting the feedstocks for sustainable
energy applications
Significance and influence of various promoters on Cu-based catalyst for synthesizing methanol from syngas: A critical review
No full textMethanol synthesis from syngas is an effective method for producing fuel additives, oxygenated fuels, and other chemicals. Several promoted catalytic systems have been tested for the synthesis of methanol. Catalysts based on noble metals are extremely active in generating methanol from syngas. However, sintering, poisoning, and related expenses accounted for the switch to Cu-based catalysts. The promotion of Cu-based catalysts, even with small doses of an effective promoter, resulted in a considerable change in product selectivity. A suitable promoter is required for Cu-based catalysts used in the synthesis of methanol because it significantly impacts the electronic, geometric, or acid/base surface properties, which in turn affect the catalyst's activity and selectivity. It also significantly impacts the interactions between the catalyst's active ingredients. However, the interactions between the active component and the promoter can be adjusted or influenced by appropriate support.
The present paper primarily focuses on several promoters in the copper-based catalyst for synthesizing methanol from syngas. Briefly deliberated on the need for Cu-based catalysts for methanol synthesis, their reaction & mechanism, cause for promoter's addition concerning their role & influence, the importance of CO2 addition in feed synthesis gas & their impact on the catalyst. This paper mainly highlights the selectivity and activity of various promoted Cu-based catalysts, although different parameters for the cause of promotion and inhibitions in the catalyst. The effect of reaction conditions, including pressure, temperature, gas hourly space velocity (GHSV), and syngas composition, is briefly reported. Herein, this paper also comprehensively compares the effects of adding various promoters in small amounts to Cu-based catalysts. This review intends to be illustrative rather than exhaustive
Experimental protocols to determine reliable organic geochemistry and geomechanical screening criteria for shales
No full textUnconventional shale petroleum systems, owing to their petroleum generation and storage properties have gained tremendous exploitation and research interest in recent years. Moreover, their emergence as potential atmospheric carbon dioxide sinks has further warranted a detailed examination of their multiple properties. Laboratory geochemical screening and geomechanical investigations provide valuable information for classifying these reservoirs. Although some guidelines exist for conducting such analyses, the analytical methods and sampling techniques applied do influence the quality of the derived measurements. For laboratory geochemical screening using the Rock-Eval technique, various factors including sample grain size, type of kerogen, sample quantity, and nature of S2 and S4 curves, all substantially influence the quality of the data generated. In this work, we summarize the different factors that influence the data generated from Rock-Eval analysis and recommend a method that involves optimization of sample weight and sizes for the generation of reliable geochemical data. A new emerging technology in the field of organic petrography for the simultaneous characterization of organic and inorganic phases in shales has also been discussed. Once source-rock potential of the shale formation is ascertained, the next step is a selection of suitable target shale reservoir zones, and designing successful hydraulic fracturing programs for the exploitation of the reservoir. For this purpose, detailed knowledge of geomechanical properties is essential. However, the quantity of intact shale-core samples recovered from coring operations is typically insufficient for reliably analyzing geomechanical properties by applying the established standards. A comparison is made between the uniaxial compressive strength and Young's modulus measurements on shale specimens of different length-to-diameter ratios. It reveals that specimens smaller than the recommended standard exhibit unacceptable variations in the values of strength and elastic parameters they generate. To overcome this, it is justified to use alternative techniques suited to the small sample sizes typically recovered in borehole shale cores. For instance, a punching tool and nanoindentation, which require small sample sizes, can both be used to reliably analyze geomechanical properties in circumstances where larger shale samples are not available from borehole zones of interest
Organic Petrological Facets and the Evolution of Paleomire, Matasukh Lignite Deposits, Rajasthan, India
No full textThe present research work attempts to understand the organo-petrological facets of the lignite hosted in the Tertiary successions in Rajasthan. The maceral diversity was analyzed qualitatively and quantitatively which recorded huminite as the dominant microscopic constituent followed by inertinite and liptinite. The rank parameter of coal evaluated through vitrinite reflectance measurement random (VRo) shows the values vary between 0.19 to 0.27% suggesting lignite in rank. The petrographic investigation point towards the primary phase of degradation of organic matter corroborated through the dominance of huminite suggesting frequent flooding and the presence of funginite, demonstrating intense fungal activity in the mire. The paleodepositional model records elevated values of gelification Index (GI) ranging from 1.63 to 3.88 with well-preserved cell structures pointing towards an early phase of coalification. The model and plot of GI and TPI show that the paleomire developed in a limnic setting
Using optical-electron correlative microscopy for shales of contrasting thermal maturity
No full textIdentifying dispersed organic matter (DOM) types present in shales with the help of a standalone scanning electron microscope (SEM) is often difficult to accomplish. Although reflected light microscopes are useful in identifying the organic matter type, they typically achieve magnification of 500× but cannot magnify beyond 2500×. Optical-electron correlative microscopy, a new technique that has recently gained popularity, involves first identifying the type of organic matter under an optical microscope before finding the same particle under SEM for a closer look at its microstructure. In this study, marginally mature in the early oil window (n = 2) and late mature at the boundary of oil window and condensate wet gas window (n = 2) shales from the Rajmahal (RM) and Jharia (Jh) Basins of India, respectively, were compared using the correlative technique. The source rock properties and the mineralogical composition of the shale samples were first evaluated using Rock-Eval 6 and X-ray diffraction (XRD) analysis, respectively. During electron microscopy analysis, SEM parameters such as brightness/contrast levels, acceleration voltage, and working distance were adjusted to make the DOM and mineral matter present in the shale samples clearly distinguishable from one another. At the acceleration voltage of 15 kV under backscattered (BSE)scanning mode and 10 kV under secondary electron (SE2) scanning mode the DOM and mineral matter were clearly discernible in both RM and Jh shale samples. However, without the correlative technique it was challenging to distinguish between the individual maceral types present in the shale samples, as all appear dark under SEM. Mineral matrix characterization using the correlative technique and energy dispersive spectroscopy (EDS) analysis enabled clay minerals in cell lumens of semifusinite to be identified in both RM and Jh shales. Under SEM, pyrite was associated with vitrinite in Jh shales, which was difficult to notice under the optical microscope. The correlative technique enabled the analysis of the organic matter-hosted porosity under SEM at higher magnifications. The sporinite in the RM shale samples was found to have SEM visible pores, whereas no pores were observed to be present within the sporinite in Jh shales. Both vitrinite and inerinite macerals observed in RM and Jh shale samples lacked any SEM-visible pore structure. The pores were found to be more obvious at a 5 kV acceleration voltage than at 10 kV in SE2 scanning mode