IR@CIMFR - Central Institute of Mining and Fuel Research (CSIR)
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Innovative InAg–carbon nanocomposites: mesoporous design for OER enhancement
No full textTo produce clean and sustainable hydrogen energy through water electrolysis, the sluggish oxygen evolution reaction (OER) needs to be accelerated sustainably by using stable and highly effective electrocatalysts. Bimetallic nanocomposites have been recently recognized as an interesting class of electrocatalysts because of their synergistic behaviour, tunable morphology, and high catalytic efficiency. Herein, InC, AgC, and InAgC nanocomposites were synthesised via a hydrothermal method using a mesoporous carbon support derived from the carbonisation of giant cane. The structural characterisation revealed that the InC composite has tetragonal In with a minor presence of cubic In2O3, whereas AgC and InAgC are well aligned with cubic Ag and tetragonal In. Electron microscopy revealed that InC has a 3D plate-like structure, while InAgC exhibits a spherical shape and is uniformly dispersed across the carbon surface. InAgC showed excellent activity and durability for the OER, with a notably low overpotential of 480 mV at a current density of 100 mA cm−2, a Tafel slope of 97 mV dec−1, and an oxygen production turnover frequency of 10.19 s−1. The chronoamperometric (i–t) study of InAgC at 1.58 V vs. RHE for 20 h in 1 M KOH indicates that the catalyst is highly stable for the OER in alkaline electrolytes. The electrochemical double-layer capacitance (Cdl) value in the non-faradaic potential region of InAgC is greater (52.14 mF cm−2) than those of mesoporous carbon (16.54 mF cm−2), AgC (33.10 mF cm−2), and InC (48.77 mF cm−2), which is attributed to InAgC having more accessible active sites for the OER. This work presents numerous possibilities for developing effective nanocomposites using giant cane as a natural carbon source
Enhancing NiS performance: Na-doping for advanced photocatalytic and electrocatalytic applications
No full textAlkali metal doping is a new and promising approach to enhance the photo/electrocatalytic activity of NiS-based catalyst systems. This work investigates the impact of sodium on the structural, electronic, and catalytic properties of NiS. Comprehensive characterization techniques demonstrate that Na-doping causes significant changes in the NiS lattice and surface chemistry translating into a larger bandgap than NiS. Photocatalytic experiments demonstrate 98.5% degradation of 2,4-DCP under visible light, attributing it to improved light absorption and charge separation by Na–NiS nanoparticles. The effect of pH and pKa on the degradation of 2,4-DCP has also been studied and reported. Additionally, electrochemical measurements of Na–NiS indicate overpotentials of 336 mV towards hydrogen evolution reaction (HER) and 350 mV towards oxygen evolution reaction (OER). The material's overall water splitting is found to be 2.61 V at a current density of 10 mA cm−2. The results highlight the potential of Na–NiS as a versatile catalyst for environmental remediation and clean energy applications, paving the way for further exploration and optimization of doped transition metal sulfides
Emergence of Fluorescent Glycodots for Biomedical Applications
No full textCarbohydrate-functionalized quantum dots exhibit excellent physical characteristics and enhance the steric interaction with biological cells and tissues. Glycoconjugation of quantum dots promotes aqueous solubility, stability, and reduced immunogenicity. Carbohydrate–protein interactions are involved in various vital processes and provide insight into cellular recognition, cell-to-cell communication, pathogenicity, antigen–antibody recognition, and enzymatic action. Quantum dots are fluorescent materials with rich quantum mechanical and unique optical properties, making them valuable for biomedical applications. Recent advancements in quantum dot materials as biomedical tools have led to the development of carbohydrate-conjugated glyco-functionalized quantum dots. These innovations promise application as nanocarriers, imaging agents, fluorescent probes, and theranostics. This review provides an overview of glyco nanotechnology, emphasizing carbohydrate-conjugated metal-, silicon-, and carbon-based quantum dots as glyco dots and their potential biomedical uses. We hope that this study will address the gap in this field and provide a more precise understanding of the subject
Pore Structural Complexities and Gas Storage Capacity of Indian Coals with Various Thermal Maturities
No full textUnderstanding pore structural complexities of coal is essential in coalbed methane (CBM) enhanced recovery and optimization of CO2 sequestration strategies. Coal’s micropores play a pivotal role in gas adsorption, while its mesopores and macropores facilitate gas migration and recovery. This study investigates the relationship between thermal maturity, maceral composition, and pore structural attributes in five coal samples with progressing thermal maturity from the Raniganj and Jharia Basins, India, using low-pressure nitrogen (N2) and carbon dioxide (CO2) adsorption techniques. A key focus is to derive fractal dimensions from CO2 adsorption data, which effectively captures micropore complexity and heterogeneity, offering critical insights into the coal’s gas storage potential. The results reveal that thermal maturity significantly impacts pore development, with postmature coals exhibiting greater micropore volumes and higher fractal dimensions, indicating higher complexity of the pore surface area and gas storage capacity. The analysis of the CO2 adsorption data proved superior to the N2 ones in characterizing micropores, which contribute significantly in estimating the maximum gas adsorption potential of coal. This study highlights strong correlations between fractal dimensions, maceral composition, and thermal maturity markers obtained from programmed pyrolysis. This work highlights that CO2-derived fractal dimension analysis coupled with organic petrography and the Rock-Eval thermal maturity parameter can be an effective way to understand the surface heterogeneity of micropores in coals and its implications for gas storage
Development of cost-effective fluorescent carbon nanoparticles as security ink for anticounterfeiting and fingerprint visualization
No full textAnticounterfeiting and latent fingerprinting have become ever-growing global demands, impacting national
economies, defence and various technological fields. This has led to an increasing need for
photoluminescent materials that are nontoxic, highly luminous, photostable, more sensitive and low-
cost. However, there is a lack of research reports that offer a detailed exploration of photoluminescent
materials for both anticounterfeiting and latent fingerprinting. Thus, we explored waste pistachio shell
biomass-derived tunable fluorescent carbon nanoparticles as an invisible/security ink for latent
fingerprint visualization and anticounterfeiting labels. Three levels of security characteristics for
fingerprint analysis were investigated to enable a more comprehensive exploration of the synthesised
fluorescent carbon nanoparticles. The invisible distinctive impression of the ridges, grooves, and furrows
of the fingers was visible on the thin layer chromatographic plate after fluorescent carbon nanoparticle-
based ink was applied to the finger under UV-light excitation. The anticounterfeiting study was
performed after labelling the prepared ink on Whatman filter paper, TLC plates, PVA films and Indian
currency to investigate its diversified applications. This study provides a new prospect for low-cost and
non-toxic photoluminescent carbon nanoparticles as invisible ink for security, encryption, and label
Major ion and stable isotope geochemistry of coalmine water of Talcher coalfield, Mahanadi Basin, India: implication to solute acquisition process and elemental flux
No full textThe major ion and stable isotope geochemistry of coalmine water of Talcher coalfield was investigated to identify prominent hydrogeochemical processes controlling mine water composition and estimate annual elemental flux. Mine water samples from opencast and underground coalmines were analysed for EC, pH, TDS, TH, major ions and stable isotopes i.e. δ18O and δ2H. Coalmine water exhibited a wide range of pH values, from highly acidic to alkaline, and were dominated by SO42− and Ca2+ in their total anionic (TZ−) and cationic (TZ+) composition respectively. Ca-Mg-SO4 was the most dominant hydrochemical facies. High contribution of Ca2+and Mg2+ and SO42− towards the TZ+ and TZ− and low HCO3−/(HCO3−+SO42−) ratio suggested a major role of sulphide oxidation in determining coalmine water chemistry. A slight deviation in the regression line towards right side of the Global Meteoric Water Line and Local Meteoric Water Line in the bivariate plot of δ18O vs δ2H implied that water experienced evaporation to some extent and originated mainly from atmospheric precipitation. Most of the mine water were undersaturated with respect to carbonate and sulphide phases. Talcher coal mines annually delivered 47.06 × 106 m3 mine water and 28.481 × 103 tonnes of solute loads into nearby drainage
Fluid Flow Analysis of a Mine Ventilation Axial Fan Using CFD Techniques
No full textVentilation is an essential component of underground mining, as it helps maintain the safety and health of miners. Consequently production and work efficiency can be enhanced. The principal purpose of the ventilation system is to regulate the quantity and quality of fresh air while eliminating hazardous gases. With the intention of increasing the energy efficacy of an axial flow fan, this study investigates the design aspects of mine ventilation fans. A three-dimensional model of the fan was developed based on the dimensions of the fan were estimated using a one-dimensional technique. A 3D model of an axial fan and a CFD analysis of its performance are investigated for underground mining ventilation application. Several cases have been studied, leading to the conclusion that the forced axial ventilation fan case, characterized by a Solidity value of 1.6, is deemed suitable for further investigation. The CFD analysis demonstrates that the forced axial flow mining fan has been designed to effectively discharge a volumetric flow rate of 47.13 m3/s of air, while operating at a rotational speed of 600 revolutions per minute. It achieves a significant static pressure rise of 838 Pascals across the rotor while consuming 48 kW of power
Pore structure evolution of Jharia coal for potential underground coal thermal treatment and associated CO2 sequestration
No full textUnderground coal thermal treatment (UCTT) is an emerging technique for clean energy extraction from coal, which also creates a unique CO2 sink environment in the form of pyrolytic char. In this study, a pathway for cleaner and efficient extraction of energy from coal is proposed. Early coalbed methane (CBM) extraction, application of UCTT followed by CO2 sequestration in pyrolytic char formed during UCTT presents an opportunity to maximize the utility of coal in new energy scenarios. To characterize Jharia coal in terms of its pore size distribution (PSD), pore surface area, pore volume, thermal evolution, CO2 adsorption attributes at low P/T (low-pressure and low-temperature), and surface morphology at different temperatures (30, 150, 300, 450, and 600 °C), a variety of analytical techniques such as low-pressure gas adsorption (LPGA), small angle X-ray scattering (SAXS), mercury intrusion porosimetry (MIP), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) were employed. The results show that the quantity of adsorbed CO2 (at low P/T) increased by 138 % for coal subjected to the maximum pyrolysis temperature of 600 °C. The PSD showed significant variations at different pyrolytic temperatures. While the pores did not show large variations when coal was heated up to 300 °C, the micropores increased sharply, while the mesopores and small macropores reduced when heated further. The elevated pyrolytic temperatures resulted in the enlargement and merging of mesopores and small macropores, along with the formation of new pores due to thermal decomposition and release of volatiles. Consequently, this contributed to a significant increase in the volume of macropores, and overall porosity. The increase in the accessibility of pores under the UCTT environment could significantly boost the CO2 storage capacity in coal
Global distribution and sources of uranium and fluoride in groundwater: A comprehensive review
No full textContamination of elements in water due to geogenic and anthropogenic activities is common around the world. Intake of contaminated water causes severe health hazards to the living community. To avoid the health hazards, World Health Organisation (WHO) has specified certain limit of the level of elements as well as ions present in the water for drinking purpose. Some common chemical contaminates in the groundwater are Uranium (U) and Fluoride (Fˉ). The intake of groundwater which is having excess amount of Uranium (U) and Fluoride (Fˉ) may lead to serious health issues. The permissible level of Uranium in water as is 30 ppb as per WHO, but in some regions due to the rock type, mining activity, chemical waste; the level of U present in water might be higher than the prescribed limit and its consumption may cause carcinogenic and non-carcinogenic diseases. As like Uranium, Fluoride has certain limit fixed by WHO that is 1.5 ppm. If the level of Fˉ is higher than 1.5 ppm it may cause dental fluorosis and skeletal fluorosis. To reduce the health risks due to intake of the elements or ions, the contaminated groundwater needs to be monitored and treated by means of constructing artificial recharge structures and other rainwater harvesting methods. However, certain ex-situ processes like membrane method, ion exchange, adsorption, and precipitation may be adopted to reduce or remove the contaminated elements/ions in the groundwater
Effect of depth and particle size on spontaneous combustion of coal in deep underground mines of Jharia coalfield
No full textSince their inception, the deep mines have faced the challenges of spontaneous heating and fire. The study examines the impact of coal seam depth and particle size on the spontaneous combustion of coal. A spontaneous heating study of seven coal samples shows moisture, volatile matter, and ash do not exhibit any clear trend except for fixed carbon, which shows a direct relationship. However, crossing point temperature (CPT) and thermo-gravimetric (TGignition) temperature reveal an inverse relationship between spontaneous combustion and the depth of the coal seam. Five size ranges: < 106, 106–212, 212–425, 425–2000, and 0–212 µm are studied, which displayed an increase in mean specific surface area (SSA) by 87% and a decrease in mean D90 value by 93%, with a decrease in particle size from 2000 to 106 µm. The reduction in particle size increases the spontaneous heating tendency by nearly 12–14%. The results show that external factors like coal seam depth, particle size, specific surface area (SSA), mining methods, and others influence spontaneous heating and fire in the Jharia coalfield. Additionally, we develop three mathematical models to forecast spontaneous heating in deep underground coal mines, considering CPT, TGignition, particle size (D90), SSA, and coal seam depth