Carbon Soot Research Articles

Enhancing the summer efficiency of solar ponds through integration of paraffin wax and carbon soot nanoparticles

Enhancing the summer efficiency of solar ponds through integration of paraffin wax and carbon soot nanoparticles

PVDF‐based nanocomposite coatings with superhydrophobic and antibacterial properties on stainless steel surfaces

AbstractIn this study, using a spray‐coating technique, stainless steel surfaces were coated with polyvinylidene fluoride (PVDF) and carbon soot nanoparticles. We imparted various surface properties onto the coatings' surfaces by varying the nanoparticle content and the preparation method. The main aim was to develop antibacterial surfaces by inducing superhydrophobic properties in stainless steel surfaces. In a one‐step preparation method, 5% and 10% of nanoparticles were insufficient to achieve superhydrophobicity, whereas 20% significantly increased the water contact angle to 153°. Morphological evaluations revealed the formation of a nano‐scale structure, which also led to a staggering antibacterial rate of 99.5% against Listeria monocytogenes. Using a two‐step preparation, soot nanoparticles were localized at the coating's top layer, which led to superhydrophobicity at a lower nanoparticle content (10%). However, the bacterial adhesion study showed a lower antibacterial rate (~93%). The difference in bacterial adhesion results was explained by various roughness structures according to the atomic force microscopy results. The developed system has a promising potential to be used as self‐cleaning and antibacterial coatings in the medical and food industries.Highlights Stainless steel surfaces were coated with PVDF and carbon soot nanoparticles Imparted various surface properties onto the coatings' surfaces Developed antibacterial surfaces by inducing superhydrophobic properties Using a two‐step, soot nanoparticles were localized at the coating's top layer Bacterial adhesion study showed a lower antibacterial rate (~93%).

Green carbon nanospheres for integrated photo-supercapacitors device with improved efficiency

Achieving a low-cost, high-yield, and environmentally acceptable synthesis of graphene is a significant problem in nanomaterials research. Hence, carbon nanospheres are receiving an increased attention. We have developed a unique and cost-effective method of producing carbon nanospheres from carbon soot. Carbon nanospheres were created using castor oil and virgin green leaf (Anisomeles Malabarica) and then thoroughly examined. When applied to dye-sensitised solar cells and the integrated photo-supercapacitor, the produced soot exhibited the same behavior as reduced graphene oxide. Photoconversion efficiency was 8.47 % in the dye-sensitised solar cells application and in the symmetric supercapacitor device application, it exhibited 11.83 mWh/cm2 of energy density and 0.3 mW/cm2 of power density which illuminated an LED bulb up to 60 s. The capacitive retention of 85.2 % was achieved after 3000 cycles. Finally, the integrated photo-supercapacitor performed about 3.3 % of the overall efficiency and 38 % of the storage efficiency.

Understanding photo-thermal and melting mechanisms in optical charging of nano and micro particles laden organic PCMs

Engineering efficient optical charging process necessitates efficient photo-thermal energy conversion, transfer, as well as storage of the incident solar radiant energy. The present work is a determining step in deciphering, quantifying, and understanding the aforementioned steps involved in the optical charging of PCMs. Herein, the effect of particle size, concentration and thermochromism have been critically investigated. In particular, detailed optical characterization and photo-thermal experimentation pertinent to non-thermochromic nanoparticles laden PCM (referred to as NP-PCM) and thermochromic micro capsules laden PCM (referred to as TMCP-PCM) has been undertaken. Detailed optical analysis points out that opposed to NP-PCM, TMCP-PCM significantly scatter the incident radiations – the diffuse transmittance (at room temperature) in the two cases being approximately 2 % and 39 % respectively. Furthermore, whereas, optical properties of non-thermochromic nanoparticles are nearly invariant to temperature changes; in the case of thermochromic microcapsules, the magnitude of scattering further increases and diffuse transmittance reaches as high as 51 % at elevated temperatures. Although, thermochromism helps in enhancing the penetration depth at elevated temperatures, but, due to significant fraction of scattering, the photo-thermal energy conversion is not that effective. In terms of temperature field, spatial-temporal temperature distribution curves reveal that temperature spread (in the liquid phase) in case of optical charging of non-thermochromic particles (carbon soot nanoparticles) laden PCMs is significantly high (as high as approximately 24 °C) relative to that observed in case of thermochromic particles (microcapsules) laden PCMs (approximately, 4 °C). The magnitude of the temperature spread (being representative of the deviation from thermostatic optical charging) clearly points out that opposed to non-thermochromic laden PCMs, nearly thermostatic optical charging can be achieved in case of thermochromic particles laden PCMs.Furthermore, in case of optical charging without thermochromic assistance, the temperature spread, peak temperatures and the melting rates increase with increase in particles concentration. Whereas, in the latter case, although the temperature spread and peak temperatures are nearly independent; the melting rates do depend on the particles’ concentration. Overall, the present work is a significant step towards accelerated-thermostatic thermal energy storage.

A Carbon Capture and Utilization Process for the Production of Solid Carbon Materials from Atmospheric CO2 - Part 2: Carbon Characterization.

This article is the second part of a study reporting the results of a novel carbon capture and utilization (CCU) process, which converts atmospheric CO2 into solid carbon materials. The CCU process combines direct air capture (DAC) with catalytic methanation, which is then followed by methane pyrolysis in a reactor filled with liquid tin. While Part 1 discussed the performance of the overall process and individual process steps regarding conversions and yields, Part 2 characterizes the solid carbon products obtained under various synthesis conditions. The effects of the pyrolysis temperature and the composition of the gas mixture from the methanation step on the solid carbon product are analyzed. Carbon powder is synthesized from methane with either H2 or CO2 as most important impurity. Carbon samples are characterized using SEM, TEM, Raman spectroscopy, XPS and XRD analysis. Very thin, disordered carbon flakes, soot aggregates and large carbon onions are identified as the main solid products of the process. Their formation mechanisms in the liquid metal-filled pyrolysis reactor are discussed.

Assessment of the public health risk caused by exposure to atmospheric emissions from an aluminum plant

Introduction. Aluminum production is accompanied by emissions of pollutants that can negatively affect the environment and public health. The study aims to determine the impact of atmospheric emissions from an aluminum plant on the health of the population of the city of Novokuznetsk based on a risk assessment. Materials and methods. The volume of maximum permissible emissions of the Novokuznetsk Aluminum Plant was used in the work. Experts calculated the maximum and average concentrations of substances at 40 exposure points. The maximum permissible concentrations of substances were determined in accordance with SanPiN 1.2.3685-21. The authors calculated the carcinogenic risk and the risk of non-carcinogenic effects in accordance with the Guidelines 2.1.10.1920-04. They carried out the classification of risk levels based on methodological recommendations 2.1.10.0156-19. 2.1.10. Results. The authors have selected pollutants were for risk assessment: inorganic dust with a SiO2 content of <20%, sulfur dioxide, benz(a)pyrene, hydrogen fluoride, carbon monoxide, nitrogen dioxide, suspended solids, nitrogen oxide, carbon (soot). The maximum concentrations were 0.1–3.77 MPC for inorganic dust (SiO2<20%), 0.1–2.64 MPC for hydrogen fluoride and 0.05–1.74 MPC for sulfur dioxide; average concentrations were up to 9.16 MPC for benz(a)pyrene. The hazard indices for acute exposure are at an acceptable level; For chronic exposures, they correspond to alarming and high levels, reaching the highest value (13.469) at a point located closer to the sources of emissions. Hazard indices for critical organs and systems in acute exposures are at acceptable or minimum (target) levels, in chronic exposures they correspond to alarming and high-risk levels. The respiratory and immune systems are most affected. The total individual carcinogenic risk ranges from 4×10–7 to 8×10–6, without exceeding the upper limit of the permissible risk. Residents of the Kuznetsk district of the city are most affected by emissions. Limitations. The main limitation in the work carried out was the use of calculated concentrations of pollutants for risk assessment without the use of in-kind indicators. Conclusion. Elevated concentrations of pollutants were detected in the atmospheric air of residential areas adjacent to the territory of the aluminum plant, which determine alarming and high levels of non-carcinogenic risk to public health. Ethics. This study did not require the conclusion of the Ethics Committee.

Assessment of the risk to the health of the population living in the zone influenced by atmospheric emissions from the engineering industry

Introduction. During operation, machine-building enterprises emit pollutants that can negatively affect the health of the population. The study aims to determine the impact of emissions from a machine–building plant, as well as background atmospheric pollution, on the health risk of the population of Novokuznetsk. Materials and methods. The work used data from the volume of maximum permissible emissions of a machine-building plant. The researchers calculated the maximum and average concentrations of pollutants using the "ECOcenter – Standard" program at 36 exposure points selected on the city map. Experts determined the maximum permissible concentrations of pollutants in the atmosphere in accordance with SanPiN 1.2.3685-21. The authors calculated the risks to public health in accordance with the Guidelines R 2.1.10.1920-04. The classification of risk levels was carried out on the basis of MP 2.1.10.0156-19. 2.1.10. Scientists also made a risk assessment considering background atmospheric pollution. Results. Specialists carried out a risk assessment from exposure to nitrogen dioxide, carbon monoxide, sulfur dioxide, carbon (soot), inorganic dust, hexavalent chromium. The maximum and average concentrations of pollutants, as well as the maximum concentrations calculated taking into account background pollution, did not exceed the maximum permissible level. The average concentrations of nitrogen dioxide and hexavalent chromium, taking into account the background, exceeded the hygienic standard. The values of the hazard indices for acute and chronic exposures without taking into account the background, as well as for acute exposures taking into account the background, corresponded to the minimum (target) risk level. The values of the hazard indices for chronic inhalation effects, considering the background, corresponded to the alarming risk level at five points, amounting to 3.084–3.800. With chronic exposure, taking into account the background, an alarming level of risk was revealed for the effect on the respiratory organs (at four points the hazard index was 3.117 to 3.616) and blood (at three points the hazard index was in the range from 3.090 to 3.433). The total individual carcinogenic risk, excluding background, did not exceed the permissible level, ranging from 1.08×10–8 to 2.43×10–7 at different points, taking into account the background, amounted to 1.79×10–4–2.26×10–4, which corresponds to an alarming level. Hexavalent chromium makes the main contribution to the formation of carcinogenic risk. Limitations. Calculated concentrations of pollutants were used to assess the risks. Conclusion. The risks from exposure to atmospheric emissions from the machine-building plant correspond to the minimum (target) level. Background concentrations of toxic substances in chronic inhalation exposures determine an alarming level of non-carcinogenic risk at five points, as well as an alarming level of carcinogenic risk at all points of exposure. Ethics. This study did not require the conclusion of the Ethics Committee.

Effective methane decomposition using spark discharge assisted laser-induced plasma: An approach based on Fourier transform infrared (FTIR) spectroscopy

The widespread utilization of fossil fuels cause to significantly elevate greenhouse gas emissions. Consequently, the developments of the innovative methods are essential to convert methane into the green energy. Recently, significant effort is made to enhance the performance of the plasma-based conversion technologies. Here, the dissociation rate of methane into heavier hydrocarbon compounds are carefully determined by making use of a hybrid laser-induced plasma (LIP) and spark discharge (SD). Fourier-transform infrared (FTIR) spectroscopy reveals a couple of characteristic peaks after laser triggering, whose intensities notably increase at higher applied voltages. The corresponding peaks indicate the formation of heavier compounds including sp and sp2 C–H stretching bonds. The findings elucidate that the methane decomposition rate notably elevates in favor of hybrid SD-LIP against that of traditional LIP. It is worth noting that the simultaneous ablative effect of the catalyst surface to remove the carbon soot by the successive laser shots could prevent the catalytic deactivation leading to the sustained performance.

Valorization of carbon soot ash for the selective capture of lead ions from industrial waste water–A waste to resource approach

Landfills are struggling to accommodate the increasing amounts of carbon soot ash waste from oil refineries. Due to extensive industrial productions, large quantities of lead ions are released into the environment, which not only pollutes the environment but also affects flora and fauna. In this work, these urgent environmental issues will be tackled by studying the use of modified carbon soot ash for specific heavy metal adsorption. Carbon soot ash modified with chemical leaching and physical ball-milling was loaded onto the surface of graphene oxide. This adsorbent was found to selectively adsorb and remove toxic lead ions (>99%) from a mixed heavy metal solution. The adsorption efficiency was found to increase with temperature (20–60 °C) and pH (2–8). Langmuir isotherm and pseudo-second order kinetics were found to fit the adsorption process through curve fitting, where the adsorbent reached a maximum capacity of 194.55 mg/g. Potential mechanisms for lead adsorption and metal specificity are also discussed here. This work aligns with the waste-to-resource pathway, where waste carbon soot ash is diverted from landfilling and is formulated as a specific heavy metal adsorbent, that shows promise for environmental remediation.

Experimental study on the effects of n-butanol and n-propanol on the spray and combustion characteristics of diesel/biodiesel blends in a constant volume combustion chamber

The depletion of fossil fuel resources and the escalating environmental impact of greenhouse gas emissions have intensified the global exploration of renewable and sustainable energy sources. Biodiesel produced from vegetable oils and animal fats has become a promising alternative to conventional diesel fuel due to its renewability and lower carbon emission. This study investigates the differences in spray, combustion and flame characteristics between soybean-based biodiesel blended with propanol and butanol at various ratios. The results indicate that the liquid spray penetration length of biodiesel mixed with propanol and butanol exceeds that of soybean-based biodiesel. And the increase of spray penetration is accompanied by a longer flame lift-off length, which indicates the improvement of spray characteristics. Regarding combustion, alcohol-fuel blends exhibit a reduction in peak combustion pressure but an increase in peak apparent heat release rate. Additionally, these fuels show a shorter ignition delay and combustion duration. The peak natural flame luminosity is lower for alcohol fuels, suggesting their potential to reduce carbon soot production and support low-carbon combustion. These experimental results contribute to advancing research on cleaner, more efficient and renewable fuels, thereby reducing reliance on conventional fossil fuels.

Activating agent-driven hierarchical nano-porous structure in mustard oil-derived carbon soot for supercapacitive application.

In the present paper, activated nano-carbon soot is derived from atmospheric flame combustion of thymol-mustard oil followed by activation with potassium hydroxide (KOH) to produce micro- and mesoporous interiors. Different forms of activated nano-carbon soot are produced by using different weight percentage ratios 1:1, 1:3, and 1:5 of precursor carbon soot (CS) to KOH and named CS11, CS13, and CS15, respectively. An increase in specific surface area and average pore volume is observed with an increase in the amount of KOH with the hierarchical network having balanced micropores as well as mesopores in CS15. The electrochemical performance of prepared activated nano-carbon soot is further investigated by the fabrication of a symmetric electric double-layer solid-state supercapacitor (SC) device utilizing a 6M KOH electrolyte. The CS15-based device displays the highest specific capacitance (Csp) of 226.20 F/g at a current density of 0.5 A/g with energy density (Ed) 31.42 Wh/kg at a power density (Pd) of 250 W/kg. The Csp, Ed, and Pd are found to be higher than activated nano-carbon soot reported in the literature. Further, three-coin cells are fabricated using CS15 which are tested in series combination with yellow light emitting diode (LED) and are found to be able to glow LED for ~ 5min 25s.

Computational fluid dynamic analysis of the effect of inlet valve closing timing on common rail diesel engines fueled with butanol–diesel blends

The inlet valve closing (IVC) timing plays a crucial role in engine combustion, which impacts engine performance and emissions. This study attempts to measure the potential to use n-butanol (Bu) and its blends with the neat diesel in a common rail direct injection (CRDI) engine. The computational fluid dynamics (CFD) simulation is carried out to estimate the performance, combustion, and exhaust emission characteristics of n-butanol–diesel blends (0%–30% by volume) for variable valve timings. An experimental study is carried out using standard valve timing and blends to validate the CFD model (ESE AVL FIRE). After validation, the CFD model is employed to study the effect of variable valve timings for different n-butanol–diesel blends. Extended coherent flame model-3 zone (ECFM-3Z) is implemented to conduct combustion analysis, and the kappa–zeta–f (k–ζ–f) model is employed for turbulence modeling. The inlet valve closing (IVC) time is varied (advanced and retarded) from standard conditions, and optimized valve timing is obtained. Advancing IVC time leads to lower cylinder pressure during compression due to reduced trapped air mass. The brake thermal efficiency (BTE) is increased by 4.5%, 6%, and 8% for Bu10, Bu20, and Bu30, respectively, compared to Bu0. Based on BTE, optimum injection timings are obtained at 12° before the top dead center (BTDC) for Bu0 and 15° BTDC for Bu10, Bu20, and Bu30. Nitrogen oxide (NOx) emissions increase due to complete combustion. Due to IVC timing, further carbon monoxide and soot formation decreased with blends and had an insignificant effect.

Optical investigation on lubricant combustion characteristics under the ammonia-methane premixed environment

The combustion process is an indispensable energy conversion step in modern industry and energy production. Especially in high-performance engines and energy conversion systems, understanding and controlling the combustion process is critical to improving efficiency and reducing environmental pollution. As a key component of mechanical systems, the combustion characteristics of lubricants at high temperatures and pressures have a direct impact on system performance and emissions. This study investigated the combustion characteristics of lubricant films in an ammonia-methane premixed environment using Planar Laser-Induced Fluorescence (PLIF) and Planar Laser-Induced Incandescence (PLII). It focused on the effects of varying ammonia concentrations on the emission of soot and polycyclic aromatic hydrocarbons (PAHs) in the constant volume combustion vessel. Experiments varied the ammonia-to-methane molar ratios, initial oil film thickness, and base oil type to study their influence on the lubricant combustion characteristics. Results indicated that ammonia significantly reduced soot formation by altering the dynamics of NH* and OH* and impacting PAH distribution. For the lubricating oil soot formation factors, the increase of the initial mean oil film thickness was more obvious for the promotion of soot formation, the increase of the unsaturated hydrocarbon content in the oil film also promoted the generation of carbon soot to a certain extent, and the initial flame energy ratio had the least influence on the promotion of soot formation. Overall, the study contributed to the understanding of the formation mechanism of soot caused by lubricating oil in zero-carbon and low-carbon blended atmospheres and provided a new insight into the interaction between nitrogen-containing zero-carbon fuels and large-carbon-number hydrocarbons, which is of great significance for controlling soot emissions from engines under zero-carbon fuel blending.

A review on waste carbon soot as a functional material for water remediation

A review on waste carbon soot as a functional material for water remediation

Electrochemical performance of MXene/Fe3O4 composite derived from recycled carbon for vanadium redox flow battery

MXenes are emerging 2D materials that have demonstrated excellent combined metallic electrical conductivity and hydrophilicity. They have been extensively studied in applications like energy storage, catalysis, optoelectronics, and so on. In this work, the carbon sourced from carbon soot extracted from fossil fuel combustion wastes was used to produce Ti3C2Tx MXene for the first time. The recyclable carbon-derived MXene/iron oxide (Fe3O4) composites with different concentrations of Fe3O4 were synthesized via a hydrothermal route. The successful synthesis of the MXene/Fe3O4 composites was confirmed by the SEM, HRTEM, EDX, UV–Vis, XRD, FTIR, and XPS analyses. Electron images morphologically revealed the existence of Fe3O4 within the as-synthesized composites, while UV–Vis spectra detected the surface plasmon resonance peaks of MXene and Fe3O4, respectively. The XRD spectra identified the crystalline structure of MXene at 5.7° (002) and 25.3° (006), as well as the magnetite Fe3O4 at 18.2° (111) and 38.2° (311), which aligned well with the presence of Ti-O and Fe-O bands observed in the FTIR data. The XPS study also confirmed the presence of the Fe element within the composites. The electrochemical performance of composite as electrode material towards the cathode VO2+/VO2+ redox reaction was investigated. The synergistic effect of both MXene and metal oxide improved the electrode kinetic activity towards the redox reaction, as evidenced by the voltage peak separation (ΔE) and the ratio of peak currents (IO/IR) values determined in cyclic voltammetry (CV), and the charge transfer process probed by electrochemical impedance spectroscopy (EIS). The specific capacity of the battery with the composites was increased along with the improvement of retention strength. The MXene/Fe3O4 5 wt% composite displayed the highest electrochemical catalytic activity with the lowest ΔE (124 mV), IO/IR of about 1, producing specific capacities of 10.2 Ah L-1 and energy efficiency of 70.1 %. The nature of MXene and Fe3O4, morphological features, and higher surface area of composites increased the kinetic activity of the electrode, enabling the composites to be potentially applied in the vanadium redox flow battery (VRFB) system.

Optical characterization of black carbon-derived DOM: Implication for the fluorescence detection of fuel combustion products in marine waters

Among pollutants released from shipping, black carbon (BC), also known as soot carbon, is of great interest due to its impacts on climate, air quality, human health and ecosystems. BC emitted from ships may enter marine waters and partially transfer to the seawater dissolved phase. In this study, we investigated the optical properties (absorbance and fluorescence) of dissolved organic matter (DOM) derived from BC particles (DOMBC) emitted by ships, which were compared to those of DOMBC of other origins (diesel-powered industrial machine, biomass burning, urban dust), and to terrestrial and marine DOM (DOMTER, DOMMAR). Ship and diesel DOMBC displayed higher ratios of fluorescence maximum intensity to dissolved organic carbon concentration (Fmax/DOC), higher specific UV absorbance at 254 nm (SUVA254), and lower fluorescence emission wavelengths than the other tested materials. The parallel factor analysis (PARAFAC)-derived fluorophores of the ship and diesel DOMBC exhibited significant correlations with the concentration of dissolved black carbon (DBC), determined using the benzenepolycarboxylic acid (BPCA) method. Based on these results, we propose the Combustion indeX (COX), to help detecting and tracking ship/fuel combustion pollutions in marine waters.

Structural and optical studies of cost-effective ZnO/CCS nanocomposites

Traditionally, candle carbon soot (CCS) considered an undesired cause of air pollution, has been technologically utilized by new advanced techniques. Among carbon family, CCS is an environmentally friendly and cost-effective material. It has potential applications in various research areas such as gas sensors, solar cells and water/oil separation. In the present work, we have synthesized ZnO/CCS nanocomposite by the simple chemical method. This nanocomposite was characterized by X-ray diffraction (XRD), UV-Vis, FE-SEM/EDX, Raman and Photo luminance spectroscopy. It was found that CCS incorporation in ZnO effectively improved their structural, optical and photochemical properties. The incorporation of CCS within the ZnO accounts for the improved light-absorption capacity, extended light-response range and better photocatalytic activity. The reported CCS-ZnO composite has potential application as a photocatalyst.

Spatial heterogeneity, sediment-water exchange, and diffusion mechanisms of organophosphate esters from river to coastal aquatic system in a typical economic circle of northern China

Organophosphate esters (OPEs) have proven to be pervasive in aquatic environments globally. However, understanding their partitioning behavior and mechanisms at the sediment-water interface remains limited. This study elucidated the spatial heterogeneity, interfacial exchange, and diffusion mechanisms of 14 OPEs (∑14OPEs) from river to coastal aquatic system. The transport tendencies of OPEs at the sediment-water interface were quantitatively assessed using fugacity methods. The total ∑14OPEs concentrations in water and sediments ranged from 154 ng/L to 528 ng/L and 2.41 ng/g dry weight (dw) to 230 ng/g dw, respectively. This result indicated a descending spatial tendency with moderate variability. OPE distribution was primarily influenced by temperature, pH, and dissolved oxygen levels. As the carbon atom number increased, alkyl and chlorinated OPEs transitioned from diffusion towards the aqueous phase to equilibrium. In contrast, aryl OPEs and triphenylphosphine oxide, which had equivalent carbon atom counts, maintained equilibrium throughout. Diffusion trends of individual OPE congener at the sediment-water interface varied at the same total organic carbon contents (foc). As the foc increased, the fugacity fraction values for all OPE homologs showed a declining trend. The distinct molecular structure of each OPE monomer might lead to unique diffusive behaviors at the sediment-water interface. Higher soot carbon content had a more pronounced effect on the distribution patterns of OPEs. The sediment-water distribution of OPEs was primarily influenced by total organic carbon, sediment particle size, dry density, and moisture content. OPEs displayed the highest sensitivity to fluctuations in ammonium and dissolved organic carbon. This study holds significant scientific and theoretical implications for elucidating the interfacial transport and driving forces of OPEs and comprehending their fate and endogenous release in aquatic ecosystems.

Diesel soot as a cost effective and efficient adsorbent of hazardous Methylene Blue-An environmental benign approach

Diesel soot - a byproduct formed by combustion of hydrocarbons is a threat to the health of society and environment. Herein, it is attempted to convert it into a resource material by utilizing it as an efficient adsorbent of dyes such as methylene blue aiming at industrial waste water treatment. The diesel soot is collected from an engine exhaust, washed with ethanol and dried. It is characterized for its chemical nature, crystallinity, surface area and morphology through Raman spectroscopy, XRD, BET, SEM and TEM techniques. Adsorption of methylene blue molecules by this soot carbon nanoparticles is studied as a function of sorbent dosage, dye concentration, pH and contact time. The diesel soot carbon nanoparticles were found to have an adsorption efficiency of 98.5 % with 26.6 mg/g adsorption capacity and requires very less contact time. Column operations with the carbon soot shows the possible industrial application in removal of dye contaminants in large quantities of water without any reduction in efficiency upto eight cycles.

Badanie efektu dławienia w pożarze tunelu

As per the emergency ventilation strategy, air velocity of 3 m/s in case of the longitudinal ventilation is sufficient for smoke control in all fire conditions. Numerical experiments were carried out with FDS software to estimate the numerical value of the critical velocity. Numerical models were realized in 0-6% slope tunnels with a 1% step for 5, 10, 20, 30 and 50 MW fires for four types of fuel: gasoline, diesel fuel, oil and firewood. The paper notes that the dynamic pressure induced by a strong fire is much higher than the static pressure of tunnel jet fans. As a result, following the algebraic summation of positively-directed ventilation flows and the negatively-directed flows induced by fire, an intense back layering occurs, which casts doubt on the suitability of the specified emergency ventilation strategy when designing the fire ventilation. The critical ventilation speed of 3 m/s cannot cope with the traction caused by fire, expressed by the ascending movement of the high-temperature and low-density combustion products. The paper discusses the numerical modelling results with an adiabatic underground heat exchange model and presents typical tunnel fire modelling plans, which correspond to an inclined tunnel for ascending and descending ventilation flows as well as a horizontal tunnel. The article gives the regularities obtained by the numerical models of changes in the variables of average air temperature and density, average carbon monoxide, average carbon dioxide and soot concentrations. According to the emergency ventilation strategy, critical velocity is an important value and a major determinant of back layering prevention in sloping tunnels. Although many papers have been devoted to this problem, the obtained results differ much. The present paper shows that strong fires induce much greater dynamic pressures than the static pressures of the tunnel jet fans are. Consequently, the flows caused by these forces, as they move in different directions, following their algebraic summation, cause a strong back-layering in case of positive ventilation flows, i.e., when the ventilation flow is descending and the fire seat is found at a lower point compared to the air supply portal. The new results can be used to develop fire ventilation plans as well as life-saving and emergency control solutions in the operating tunnels for personnel and rescuers.