IR@CIMFR - Central Institute of Mining and Fuel Research (CSIR)
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Singlet oxygen driven enhanced photocatalytic degradation of 1,3,7-tri�methylpurine-2,6-dione using surfactant mediated PVA-CuO nanocomposites: Combining physical adsorption and photocatalysis
No full textDespite significant progress in the synthesis of metal nanoparticles, repeatability is a major bottleneck. The
difficulty can be attributed to the synthetic methods, precursor materials, and surfactants used for surface
modification. To provide a better understanding of the role of surfactants in materials synthesis, properties, and
applications, this work reports the effect of surface modifiers using three different surfactants: cationic (cetyl
trimethyl ammonium bromide, CTAB), anionic (sodium lauryl sulfate, SLS), and non-ionic (Tween 80, T80). The
effect of these surfactants on the catalytic properties and the degradation efficiency of the polymeric matrix
(CuO/PVA) has been investigated using 1,3,7-Trimethylpurine-2,6-dione (caffeine) as a major pollutant. From
the kinetics studies, R2 = 0.9939 for Freundlich isotherm and 0.9839 for pseudo-first-order kinetics indicate that
the reaction in the dark follows the Freundlich isotherm, whereas the adsorption of the pollutant on the catalyst
surface follows pseudo-first-order kinetics. In addition, the surface modification has a greater impact on the
degradation of caffeine as evident from the 29% higher degradation ability of the CTAB-assisted polymeric CuO
compared to its unmodified counterpart. Surface characterization of the obtained polymeric matrix revealed that the degradation is also affected by the smaller particle size, band gap, and morphology of the catalyst. The
scavenging experiments suggest significant involvement of the singlet oxygen in the degradation of caffeine by
reducing the degradation to 49.8% from 96.5% after the addition of the scavenger. Herein, a simplified view of
the variable catalytic affinity brought about by the surface modifications of the photocatalyst with respect to the
surfactant employed during the synthesis has been presented
Phosphorous concentration in iron-rich rocks of the Chilpi Group, Bastar Craton, India: implications on late Palaeoproterozoic seawater palaeo-productivity
No full textThe concentration of the bio-limiting nutrient element, phosphorus (P), in seawater is important for primary marine productivity and the evolution of life on geological time scales. The molar percentage of P/Fe in banded iron formations (BIF) and iron oxide-rich chemical sediments is a good proxy for the first-order approximation of seawater P concentration. Bio-available concentration of phosphorus in Precambrian, especially during the late Palaeoproterozoic Era (2.0–1.8 Ga), is poorly constrained. We evaluated the P/Fe ratios of iron-rich rocks from the late Palaeoproterozoic Chilpi Group, Bastar Craton, Central India. The bulk rock molar percentage of P/Fe ratios of the Chilpi rocks vary between 0.11 and 1.17 (average 0.51 ± 0.3), and the average of EPMA spot analysis P/Fe molar ratio is 0.32 ± 0.4; both have values similar to Archaean BIFs of the world. The observed low molar ratio is not an artefact of contamination from terrestrial sources, diagenetic alterations or high-temperature hydrothermal inputs; it indicates the deposition from phosphorus-lean seawater. The modelled P/Fe molar ratio in the Chilpi Group suggests that the concentration of phosphorus in the shallow marine environment was less than 0.12 μM. The low level of phosphorus concentration in seawater during the late Palaeoproterozoic Era is interpreted to be a consequence of the low primary production during a period of low atmospheric oxygen content, which might have impeded the evolution of eukaryotes
Metal contamination of groundwater in the mica mining areas of Jharkhand: Assessing seasonal variation, sources and human health risk.
No full textThe concentrations of metals in the groundwater were assessed on a seasonal basis to evaluate the possible risk on the local populace via the drinking water pathway in the mica mining areas of Jharkhand in India. Significant temporal variations were observed in the concentration of metals with the highest values being in the post-monsoon season. Spatial variations were also illustrated with higher metals observed in the areas with mining and vehicular activities. Al, Fe and Mn were the metals of major concern, which surpassed the drinking water quality standards at many locations. Considering all the seasons, Al, Fe and Mn exceeded the standards in 72%, 47% and 33% of samples, respectively. The metal concentrations in groundwater of the area can be ascribed to both natural sources and human activities as is depicted from principal component analysis, which resulted in extraction of four factors explaining 66.6% of data variance. For the evaluation of the non-carcinogenic human health risk, Hazard Quotients (HQ) and Hazard index (HI) were calculated as per United States Environmental Protection Agency methodology. Taking into account the geometric mean of the metal concentration in the groundwater, the hazard quotients did not exceed unity for any metal in any season advocating that the metals individually did not pose risk to the consumers of the groundwater. However, the cumulative risk of all the considered the metals as depicted by the Hazard Index suggests appreciable risk to the child population in the pre-monsoon (HI = 1.17) and post monsoon (HI = 1.18) seasons. The health risk assessment identified the child population being more vulnerable to non-carcinogenic risk as compared to the adults. Also, the risk was highest during the post-monsoon season as weighed against the other two seasons. Location-wise HI suggests the groundwater being unfit for drinking in more than 50% of the locations
Enhanced corrosion protection of Cu & Al in Saline media using a new PEDOT based waterborne polyurethane coating
No full textn the present investigation, a new nanocomposite (PGZ) viz. PEDOT (poly(3,4-ethylenedioxythiophene)/ Graphene oxide (GO)/Zirconia (ZrO 2) has been developed via in-situ chemical oxidative polymerization method. Its electrochemical response as a preventive coating for inflating the corrosion resistance of industrial alloys i.e. copper (Cu) and aluminum (Al) exposed to neutral chloride (3.5% NaCl) environment at room temperature has been analyzed using various electrochemical techniques. Both the substrates along with the nanocomposite material (PGZ) have been characterized by various surface analysis studies viz. FE-SEM, XRD, TGA, TEM, EDAX and FT-IR studies. The SEM studies showed the compact formation of coating on the substrate. Other characterization studies well established the formation of PGZ nanocomposite. The experimental electrochemical investigations on coated substrates demonstrated a significant reduction in the corrosion current density (
) and a fascinating increase in the charge transfer resistance (
) values in comparison to the bare metal specimens
Effect of poly-aniline coated iron ore mining waste (PANI@IOMW) as efficient adsorbent on mitigation of Cr (VI) from aqueous solution: Experimental and statistical investigation
No full textPresent investigation is focused on the synthesis of poly-aniline coated iron ore mining waste (PANI@IOMW) adsorbent and its utilization for remediation of Cr (VI) from water using batch process. The studied adsorbent shows excellent Cr (VI) mitigation properties with highest efficiency of 99% at significantly low dosage of 0.15 g, pH 2.0, 90 min contact time and 50 mgL−1initial concentrations. Non-linear regression analysis shows that Freundlich isotherm is considers as a suitable model for mitigation of Cr (VI) with Qmax of 73.29 mg/g for 50 mgL−1 Cr (VI) concentration. Pseudo second order kinetics model is considered as a best fitted model for the present investigation. Thermodynamic study shows that adsorption is spontaneous and endothermic in nature. The value of mean free energy (0.983 J/mol at 303 K) and activation energy (7.96 kJmol−1 at 303 K) shows that adsorption of Cr (VI) on PANI@IOMW occurs through physisorption. Surface study of PANI@IOMW was done using FESEM, EDX, FTIR, XRD, XRF, XPS, HR-TEM and AFM analysis. The comparison of % efficiency of Cr (VI) removal obtained by response surface methodology (RSM) (99.06%) and experimental studies under the optimum conditions (99%) suggested that quadratic model is suitable model for Cr (VI) adsorption. The adsorbent PANI@IOMW shows regeneration ability up to two cycles without losing its properties. Thus PANI@IOMW adsorbent can be used for treatment of water containing Cr (VI) as good alternative as compared to chemical adsorbents used by the industries
Decoding rate of penetration of tunnel boring machine in Deccan Traps under varied geological and machine variables using response surface analysis
No full textPerformance of TBM is significantly influenced by the ground conditions and machine variables. To achieve an optimum rate of penetration (ROP) during TBM excavation, it is important to assess the interaction between rock mass properties and machine operational/performance variables. This paper presents a systematic analysis of TBM performance based on the data collected from the MetroLine-3 UGC-01 project in Mumbai, India, and proposes a few performance prediction models for the Deccan Traps. The current work attempted to bring out the combined effect of RQD × Js as a single predictor variable while suggesting a reliable RSA modeling technique which considers the simultaneous interaction of variables. The database consisted of engineering-geological and machine variables; the selected variables were analyzed using artificial neural networks (ANN) for identifying the significant variables. Subsequently, multivariate regression (MVRA) and response surface analysis (RSA) were utilized to develop a model for predicting TBM ROP. The first model developed using MVRA as a function of rock mass variables yielded a coefficient of determination (R2) of 0.80, whereas the second composite model developed as a function of geological and machine variables yielded an R2 of 0.85. The third model was developed utilizing RSA which resulted in 2FI (two-factor interaction) model with improved R2 of 0.88. Further, the best-performing RSA model accuracy is compared with the existing models and subsequently validated using new datasets and yielded an R2 of 0.79. The developed model equation indicates that UCS, RQD × Js, and thrust variables show significant influence on the TBM ROP
Advancements in PET Packaging: Driving Sustainable Solutions for Today’s Consumer Demands
No full textThis work provides an overview of the importance of recycling PET waste to reduce the environmental impact of plastic waste, conserve natural resources and energy, and create jobs in the recycling industry. Many countries have implemented regulations and initiatives to promote the recycling of PET waste and reduce plastic pollution, such as extended producer responsibility (EPR) systems, bans on certain single-use plastics, and deposit–return systems for plastic bottles. The article further underscores the versatility of recycled PET, as it can be transformed into various products such as fibers, sheets, film, and strapping. These recycled materials find applications in numerous sectors including clothing, carpets, upholstery, and industrial fibers. Recognizing the importance of collaboration among governments, industries, and individuals, we emphasize the need for sustainable PET waste management practices and the promotion of recycled materials. The article also provides information on India’s experiences with PET waste management and regulations in other countries. It is important to note that the global production and consumption of PET have increased significantly in recent years, with the packaging industry being the largest consumer of PET. This has resulted in a significant increase in the generation of PET waste, which poses a significant environmental and health hazard if not managed properly. PET waste can end up in landfills, where it can take hundreds of years to decompose, or it can end up in the oceans, where it can harm marine life and the environment. Therefore, the proper management and recycling of PET waste are essential to mitigate these negative impacts. In terms of India’s experiences with PET waste management, several initiatives have been implemented to promote the recycling of PET waste. For example, the government has launched the Swachh Bharat Abhiyan campaign, which aims to promote cleanliness and sanitation in the country to promote waste segregation and recycling
Natural sub‑bituminous coal as fller enhances mechanical, insulation and fame retardant properties of coir–polypropylene bio‑composites
No full textAdditives provide substantial improvement in the properties of composites. Although biobased composites are preferred over synthetic polymer and metal-based composites, they do not have
the requisite properties to meet specifc needs. Hence,
organic, inorganic and metallic additives are included
to improve the properties of bio-based composites.
Coal is a readily available resource with high thermal insulation, fame resistance and other properties.
This work demonstrates the addition of 20–30% natural sub-bituminous coal as fller for coir-reinforced polypropylene (PP) composites and exhibits an
increased tensile strength by 66% and fexural
strength by 55% compared to the composites without
any fller. Such composites are intended for insulation
applications and as a replacement for gypsum-based
false ceiling tiles. Various ratios of coal samples
were included in the composites and their efect on
mechanical, acoustic, thermal insulation, fame and
water resistance have been determined. A substantial
improvement in both fexural and tensile properties
has been observed due to the addition of coal. However, a marginal improvement has been observed in
both thermal conductivity (0.65 W/mK) and fame
resistance values due to the presence of coal. Adding
coal increases the intensity of noise absorption, particularly at a higher frequency, whereas water sorption
of the composites tends to decrease with an increase
in the coal content. The addition of coal improves
and adds unique properties to composites, allowing
coir–coal–PP composites to outperform commercially
available gypsum-based insulation panels
Trace element contamination in soils surrounding the open-cast coal mines of eastern Raniganj basin, India
No full textTrace element pollution of soils surrounding coal-mining areas affects the health of local communities. The increasing coal-mining and associated activities in the Raniganj basin (east India) have led to increased soil concentration of certain trace elements. To quantify the elevated trace element (TE) concentrations in the soil surrounding coal-mining areas, 83 surface soil, coal, and shale samples were collected from open-cast mining areas of the eastern Raniganj basin. The soils present are sandy silt, silty sand, and silty in nature, but almost no clay. They are acidic (pH = 4.3) to slightly alkaline (pH = 7.9) with a mean electrical conductivity (EC) of 340.45 µS/cm and a mean total organic carbon (TOC) of 1.80%. The northern and western parts of the study area were found to be highly polluted by certain metallic trace elements. The relevant environmental indices, geoaccumulation index (Igeo), contamination factors (CF), enrichment factors (EF), and pollution load index (PLI) were calculated and assessed. Analysis revealed that Cr was highly enriched in these soil samples, followed by Pb, Co, Cu, Cd, Fe, Ni, Mn, Zn, As, and Al. Geostatistical analyses (correlation coefficients and principal component analysis) indicated that the occurrence of some trace elements (Al, Cd, Co, Cu, Fe, Mn, Ni, and Zn) is most likely linked to the various coal-mining operations in the study area. However, the anomalous Cr and Pb distributions are likely influenced by other anthropogenic, mainly industrial, inputs besides coal mining. These results justify the adoption of rigorous soil monitoring programs in the vicinity of coal-mining areas, to identify pollution hotspots and to develop strategies to reduce or mitigate such environmentally damaging pollution
Significance of temperature and pressure on minimum fluidization velocity in a fluidized bed reactor: An experimental analysis
No full textThis investigation addresses the minimum fluidization velocity (Umf) determination in a refractory insulated fluidized bed reactor (FBR) of 200 mm ID. Umf is determined with respect to different particle sizes and operating parameters like temperature and pressure up to 900 °C and 1 MPa respectively. This study has the main thrust into the establishment of Umf at
elevated temperature and pressure during the thermochemical process, involving uniform mixing of gas-solid by fluidization phenomena at a pilot scale FBR. So, to understand the significance and impact of temperaturealong with pressure on Umf, a set of fluidization experiments have been
demonstrated in FBR. Two waste materials are abundantly available, similar to Geldart’s group-B type bed materials, i.e. Calcined-clay and Coal-ash of an average size of 1.04 and 0.92 mm respectively, and apparent density of 883
and 850 kg/m3 respectively, have been selected as bed material.
Experimental results revealed that Umf directly relates to particle size and
inverse relationship with operating temperature and pressure. Results
revealed that Umf decreases by 59.7% and 59.2% for both bed materials such as Calcined-clay and Coal-ash respectively as the temperature increases from 30 to 900°C at atmospheric pressure. Similarly, Umf also decreases by 63.3% and 66.0% for bed materials such as Calcined-clay and Coal-ash respectively as the pressure increases from atmospheric pressure to 1 MPa at room temperature. An empirical model has been developed for predicting Umf at elevated temperature and pressure during fluidization phenomena. The experimental Remf shows a good agreement with the predicted Remf by using the developed model proving its robustness