Particle Chemical Composition Research Articles

Airborne metal nanoparticles released by azides detonation: determination and potential public exposure

Metal azides are highly energetic materials that release a large amount of gas upon detonation. They also release metal particles, generating an aerosol. The most common azide is sodium azide (NaN3), which is used nowadays in car airbags. If the decomposition is not complete, harmful azide particles might be inhaled. Heavy metal azides find application as a primary explosive (primer) in ammunition. Public health officials have raised concerns about heavy metal particles released during training in shooting ranges. We identify a lack of knowledge on airborne metal particles properties released from azide detonation and on the analytical methods applied to characterize them. As a case study, we detonated milligram amounts of silver azide, copper azide, and a mixture of them in a glove box. We then analyse the airborne particles with an ensemble analytical setup, able to measure real-time their particle size distribution and chemical composition. We detected spherical metal nanoparticles in the range of 2–500 nm. These findings and the developed analytical tools may allow identifying airborne nanoparticles the passenger compartments of vehicles after airbag activation as well as in indoor shooting ranges, contributing to the evaluation of public health risks.

Anthropogenic and biogenic pollutants in a forested environment: SPRUCE-22 campaign overview

The SPRUCE-22 field campaign was conducted during July 2022 on a remote mountainous forested site in Greece to assess interactions of biogenic and anthropogenic pollutants in the Eastern Mediterranean. Particle chemical composition and size distributions along with concentrations of organic and inorganic gases were measured at high temporal resolution, while samples were collected and analyzed off-line. PM1 had a surprisingly high average concentration of 13 μg m−3 consisting primarily of organics (57%), followed by sulfate (30%), ammonium (9%), and black carbon (2%). Nitrates (both inorganic and organic) were less than 1% of the PM1 despite the relatively high NOx emissions in the Balkans. The PM2.5 concentrations at this remote site were similar and even higher than those in major cities across Greece including Athens, indicating the importance of regional transport for summertime pollution in the Eastern Mediterranean. The relatively constant average diurnal profiles of major anthropogenic pollutants are consistent with only minimal effects from local sources. Sulfates are not any more the dominant component of fine PM in Greece due to the reduction of SO2 emissions of coal-burning powerplants. The organic aerosol (OA) was quite oxidized with an average oxygen to carbon ratio (O:C) equal to 0.83. The average concentration of isoprene was 0.6 ppb, of monoterpenes 0.5 ppb, while the biogenic secondary organic aerosol factor (obtained through source apportionment analysis) was estimated to contribute 22% of the OA. Additional biogenic secondary organic aerosol (SOA) may be part of the two oxygenated OA (OOA) factors that were also identified. Radiocarbon analysis indicated that the non-fossil carbon was approximately equal to the sum of the biogenic and the more oxidized oxygenated OA, implying that the less oxidized OOA in this study was mostly associated to anthropogenic fossil fuel combustion. The biogenic SOA was quite aged (O:C equal to 0.63) and was also mostly transported to the site. Nearby new particle formation events occurred during 20 % of the days, with an average SO2 concentration of 0.3 ppb. The oxidative potential of the PM per unit of mass was quite high. The source attribution of the fine PM and the interactions among its anthropogenic and biogenic components are also discussed.

Soil Carbon Fractions under Vetiver Grass in Australia and Ethiopia Relative to other Land Uses

AbstractThe allocation of soil organic carbon (SOC) to its component fractions can indicate the vulnerability of organic carbon stocks to change. The impact of vetiver on the composition and distribution of SOC can provide a complete assessment of its potential to sequester carbon in soil.Purpose: This study quantified the distribution and impact of SOC under vetiver and the allocation of SOC to particulate (POC), humus (HOC) and resistant (ROC) fractions differentiated based on particle size and chemical composition under vetiver grass compared with other plant types.Methods: Carbon fractions were measured on soil samples collected from Australia and Ethiopia to a depth of 1.0 m under three plant communities (vetiver, coffee, and Australian native pastures). We used the MIR/PLSR spectra to estimate SOC fractions based on fractionated, and NMR measured values.Results: The stocks of SOC fractions indicated significant differences in the proportion of labile POC to HOC across sites and vegetation types. The dominant carbon fraction was HOC (71%) for all vegetation types. The average carbon sequestration rate under vetiver for OC was − 2.64 to + 7.69 Mg C ha− 1 yr− 1, while for the POC, HOC and ROC was 0.04 to + 1.17, -3.36 to + 4.64 and − 0.35 to + 1.51 Mg C ha− 1 yr− 1, respectively.Conclusion: Growing vetiver and undisturbed native pastures has on average a high accumulation rate of a more stable carbon (HOC) which is less vulnerable to change, and change was largely driven by the HOC fraction. We, therefore, recommend the use and promotion of perennial tropical grasses like vetiver and similar grasses and undisturbed native pastures as potential options to facilitate soil carbon sequestration.

Hierarchically, Low Band Gap Nanohybrid InVO4-CdS Heterojunction for Visible Light-Driven Toxic Organic Dye Degradations.

The synthesis of InVO4-CdS heterojunction photocatalysts has been achieved by a novel two-step approach, including a microwave-assisted technique, followed by a moderate hydrothermal method, marking the first successful instance of such a synthesis. X-ray diffraction, field-emission scanning electron microscopy, elemental color mapping, high-resolution transmission electron microscopy, UV-vis diffuse reflectance spectroscopy, Raman analysis, photoluminescence, X-ray photoelectron spectroscopy, and Brunauer-Emmett-Teller were employed to investigate the crystal structures, surface morphologies and particle sizes, chemical compositions, and optical characteristics of the as-synthesized materials. The research results indicated that the heterojunction InVO4-CdS, as synthesized, consisted of InVO4 microrods with an average size of around 15 nm and cadmium sulfide (CdS) microflowers with a diameter of 1.5 μm. Furthermore, all of the heterojunctions had favorable photoabsorption properties throughout the visible-light spectrum. The photocatalytic efficiency of the samples obtained was thoroughly assessed by the degradation of acid violet 7 (AV 7) under visible light irradiation with a wavelength greater than 420 nm. The photocatalytic efficiency for the decomposition of AV 7 was greatly enhanced in the InVO4-CdS (IVCS) heterojunctions when compared to prepared bare InVO4 and CdS. Additionally, it was observed that the composite material consisting of IVCS 3 wt % InVO4 combined with CdS exhibited the most significant enhancement in catalytic effectiveness for the photodegradation of AV 7 dye. Specifically, the catalytic performance of this composite material was found to be around 69.4 and 76.2 times greater than that of pure InVO4 and CdS, respectively. Furthermore, the experimental procedure including active species trapping provided evidence that h+ and •O2- radicals were the primary active species involved in the photocatalytic reaction process. Additionally, a potential explanation for the improved photocatalytic activity of the InVO4-CdS heterojunction was presented, taking into account the determination of band positions.

Recycling kaolin from paper waste and assessment of its application for paper coating

In the cellulose industry, the paper coating process plays an essential role in reducing manufacturing costs while increasing the quality of the products. Given that cellulose products are being used increasingly, the ability to recycle and reuse these materials might be highly beneficial in this industry. Thus, kaolin—one of the most commonly utilized ingredients in the cellulose industry that has a major impact on the final quality—was recycled from paper waste for this study. Then, to confirm the successful recycling process, the particle distribution, morphology, and chemical composition of recycled kaolin were analyzed by DLS, SEM/EDS, FTIR, XRF, and XRD. The related results verified the recycled kaolin's high purity and crystallinity. Subsequently, coatings with thicknesses of 30, 60, 90, and 120 μm were applied to paper using a suspension of recycled kaolin. Their mechanical properties (burst strength and tensile strength), permeability (air passage, the amount of which indicates the porosity of the paper structure), wettability (the contact angle can reveal the wetting ability of the paper), and water absorbance (the Cobb test) were then assessed. The pertinent findings demonstrated that applying a coating considerably improves paper quality. So, a coating with a thickness of 30 µm is superior to uncoated paper. In addition, among all the coating thicknesses, the treatment with the best mechanical strength, permeability, contact angle, and Cob value values had a coating thickness of 120 µm. The corresponding values for the tensile index, burst index, air passage amount, and contact angle are 70 kNm/kgr, 3.61kPa m2/gr, 680 ml/min, and 46֯ ±2. Consequently, the 120 µm-thickness treatment was determined to be the most effective one in this investigation.

A Systematic Genotoxicity Assessment of a Suite of Metal Oxide Nanoparticles Reveals Their DNA Damaging and Clastogenic Potential.

Metal oxide nanoparticles (MONP/s) induce DNA damage, which is influenced by their physicochemical properties. In this study, the high-throughput CometChip and micronucleus (MicroFlow) assays were used to investigate DNA and chromosomal damage in mouse lung epithelial cells induced by nano and bulk sizes of zinc oxide, copper oxide, manganese oxide, nickel oxide, aluminum oxide, cerium oxide, titanium dioxide, and iron oxide. Ionic forms of MONPs were also included. The study evaluated the impact of solubility, surface coating, and particle size on response. Correlation analysis showed that solubility in the cell culture medium was positively associated with response in both assays, with the nano form showing the same or higher response than larger particles. A subtle reduction in DNA damage response was observed post-exposure to some surface-coated MONPs. The observed difference in genotoxicity highlighted the mechanistic differences in the MONP-induced response, possibly influenced by both particle stability and chemical composition. The results highlight that combinations of properties influence response to MONPs and that solubility alone, while playing an important role, is not enough to explain the observed toxicity. The results have implications on the potential application of read-across strategies in support of human health risk assessment of MONPs.

Improving Aerosol Characterization Using an Optical Particle Counter Coupled with a Quartz Crystal Microbalance with an Integrated Microheater.

Aerosols, as well as suspended particulate matter, impact atmospheric pollution, the climate, and human health, directly or indirectly. Particle size, chemical composition, and other aerosol characteristics are determinant factors for atmospheric pollution dynamics and more. In the last decade, low-cost devices have been widely used in instrumentation to measure aerosols. However, they present some issues, such as the problem of discriminating whether the aerosol is composed of liquid particles or solid. This issue could lead to errors in the estimation of mass concentration in monitoring environments where there is fog. In this study, we investigate the use of an optical particle counter (OPC) coupled to a quartz crystal microbalance with an integrated microheater (H-QCM) to enhance measurement performances. The H-QCM was used not only to measure the collected mass on its surface but also, by using the integrated microheater, it was able to heat the collected mass by performing heating cycles. In particular, we tested the developed system with aerosolized saline solutions of sodium chloride (NaCl), with three decreasing concentrations of salt and three electronic cigarette solutions (e-liquid), with different concentrations of propylene glycol and glycerin mixtures. The results showed that the OPC coherently counted the salt dilution effects, and the H-QCM output confirmed the presence of liquid and solid particles in the aerosols. In the case of e-liquid aerosols, the OPC counted the particles, and the HQCM output highlighted that in the aerosol, there were no solid particles but a liquid phase only. These findings contribute to the refinement of aerosol measurement methodologies by low-cost sensors, fostering a more comprehensive understanding.

Measurement report: Bio-physicochemistry of tropical clouds at Maïdo (Réunion, Indian Ocean): overview of results from the BIO-MAÏDO campaign

Abstract. The BIO-MAÏDO (Bio-physicochemistry of tropical clouds at Maïdo: processes and impacts on secondary organic aerosols formation) campaign was conducted from 13 March to 4 April 2019 on the tropical island of Réunion. The main objective of the project was to improve understanding of cloud impacts on the formation of secondary organic aerosols (SOA) from biogenic volatile organic compound (BVOC) precursors in a tropical environment. Instruments were deployed at five sites: a receptor site, Maïdo Observatory (MO) at 2165 m a.s.l. and four sites along the slope of the Maïdo mountain. Observations include measurements of volatile organic compounds (VOCs) and characterization of the physical, chemical and biological (bacterial diversity and culture-based approaches) properties of aerosols and cloud water. Turbulent parameters of the boundary layer, radiative fluxes and emissions fluxes of BVOCs from the surrounding vegetation were measured to help interpret observed chemical concentrations in the different phases. Dynamical analyses showed two preferred trajectory routes for air masses arriving at MO during the daytime. Both trajectories correspond to return branches of the trade winds associated with upslope thermal breezes, where air masses likely encountered cloud processing. The highest mixing ratios of oxygenated VOCs (OVOCs) were measured above the site located in the endemic forest and the highest contribution of OVOCs to total VOCs at MO. Chemical compositions of particles during daytime showed higher concentrations of oxalic acid, a tracer of cloud processing and photochemical aging, and a more oxidized organic aerosol at MO than at other sites. Approximately 20 % of the dissolved organic compounds were analyzed. Additional analyses by ultra-high-resolution mass spectrometry will explore the complexity of the missing cloud organic matter.

Performance Analysis of Ferronickel Slag-Ordinary Portland Cement Pervious Concrete.

It is unknown whether Ferronickel slag (FNS)-ordinary Portland cement (OPC)-based pervious concrete (FOPC) is feasible. To this end, a feasibility study was conducted on FOPC. Firstly, a detailed microscopic examination of the FNS powder was conducted, encompassing analyses of its particle size distribution, SEM, EDS, and chemical composition. These analyses aimed to establish the suitability of a composite of FNS and OPC as a composite cementitious material. Subsequent experimentation focused on evaluating the compressive strength of the composite paste material with varying mixed proportions, revealing a slight reduction in strength as the FNS substitution rate increased. Furthermore, the study designed eighteen different mix proportions of FOPC to investigate the key physical properties, including porosity, density, compressive strength, and the coefficient of permeability. Findings indicated that increases in the cementitious material proportion correlate with enhanced concrete strength, where the ratio of cementitious to aggregate increased by 6.7% and 16.5%, and the strength of FOPC increased by 10-13% and 30-50%, respectively. Conversely, a rise in the FNS substitution rate led to a reduction in compressive strength across different mix ratios. Additionally, the ratio of paste material to aggregate was found to significantly influence the permeability coefficient. These comprehensive performance evaluations suggest that incorporating FNS into OPC for pervious concrete applications is a feasible approach, offering valuable insights for the promotion of waste reuse and the advancement of energy conservation and emissions reduction efforts.

Authigenic Barite in Tailing Dumps: Mineralogical and Geochemical Data and Results of Physico-Chemical Modeling

On the example of the Novo-Ursk tailing dump (Salair Ridge), the typomorphic characteristics of barite are considered. It was found that in the dumps, in addition to residual barite from pyrite-polymetallic ores, there are its authigenic varieties. Ore barite grains are found in the form of fragments of irregular shapes, less often grains of a tabular habit, have a dimension of 50–400 microns, Sr up to 1.41 wt.%. Newly formed barite occurs as single grains or clusters of round and elongated shapes or acicular crystals, ranging in size from 1–2 µm to larger aggregates that form veinlets or clusters in the siliceous matrix in association with jarosite and/or anhydrite. Among the impurities, Pb up to 6.33 wt.% was noted, less often Fe up to 0.73 wt.%, Sr up to 0.94 wt.%. It was shown by using thermodynamic modeling that the concentrations of Ba, SO4, Fe and Ca in solution vary within several orders of magnitude when the mineral composition of the tailings mound zones changes depending on the Eh–pH conditions of their formation. It has been suggested that the formation of barite along with pyrite may occur as a result of the action of a reductive biogeochemical barrier or a sulfate concentration barrier in the deeper parts of the section where supersaturation is achieved.The most informative typomorphic feature proving that barite was formed under tailings conditions is particle morphology, mineral association and chemical composition.

Abstract 2070: Engineered Inhalation nanoparticle formulation for lung cancer

Abstract Background: Lung cancer is a predominant cause of cancer-related morbidity and mortality across the world including in the United States. Treatment modalities for lung cancer include surgery, chemotherapy, radiotherapy, and/or targeted therapies depending on the cancer stage. Despite the survival benefits of chemotherapy, its value is offset by severe systemic side effects such as renal and/or hepatic toxicity or insufficient amounts of drug reaching to the target site. Such pitfalls can be handled by inhalable therapy which avoids first-pass metabolism and increases patients' compliance. In this study, we have investigated the inhalable therapy of cross-linked tannic acid-based nanoparticles (CTA NPs) into cancer cells and determined the synergistic effect of gambogic acid (GA) and gemcitabine (Gem). Methods: The CTA NPs formulations were characterized for particle size, chemical composition, and drug loading efficiency using various physicochemical methods (FT-IR, DSC, SEM, and TGA). Cellular uptake of CTA NPs was evaluated in lung cancer cell lines (A549 and NCI-H1299) using fluorescence microscopy and flow cytometry analysis. Further, the therapeutic efficacy of GA-Gem encapsulated CTA NPs (G-G CTA NPs) formulation was determined by various in vitro assays (CCK-8, mucoadhesion Boyden chamber, and apoptosis assays). The molecular effects of G-G CTA NPs formulation were also observed in lung cancer cell lines. Results: Our novel CTA NPs formulation provided an average size of 110 nm in dynamic light scattering with a sustained release of the drug(s). CTA NPs formulation showed a remarkable mucoadhesion and mucopenetration penetration potential in-vitro model(s). Cellular uptake studies show that CTA NPs formulation allows for effective endosomal release into the cytosol. Additionally, the G-G CTA NPs formulation showed superior in vitro anti-cancer activity in lung cancer cells (A549 and NCI-H1299) compared to free drugs. Conclusions: Taken together, our results demonstrate that G-G CTA NPs formulation exhibits superior anti-cancer potential than free drug against lung cancer and could be a novel therapeutic modality for the management of lung cancer. Citation Format: Rahul Tiwari, Eswara N. Ghali, Neeraj Chauhan, Vivek Kashyap, Subhash C. Chauhan, Murali M. Yallapu. Engineered Inhalation nanoparticle formulation for lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2070.

Effects of volatile organic compounds and new particle formation on real-time hygroscopicity of PM2.5 particles in Seosan, Republic of Korea

The hygroscopicity of PM2.5 particles plays an important role in PM2.5 haze in Northeast Asian countries by influencing particle growth and chemical composition. New particle formation (NPF) and atmospheric volatile organic compounds (VOCs) are factors that influence particle hygroscopicity. However, the lack of real-time hygroscopicity measurements has deterred the understanding of their effects on particle hygroscopicity. In this study, two intensive monitoring campaigns were conducted during the summer of 2021 and spring of 2022 using real-time aerosol instruments, including a humidified tandem differential mobility analyzer (HTDMA), in Seosan, Republic of Korea. The hygroscopicity parameter κ was calculated from the real-time HTDMA measurement data (κGf). The diurnal variations in κGf exhibited strong inverse linear correlations with the total concentration of VOCs (CTVOC) during the two campaigns. The higher atmospheric CTVOC in summer increased the growth rate of the particle diameter from 10 to 40 nm (6 nm/h) compared with that in spring (2.7 nm/h), resulting in a faster change in κGf for 40-nm particles in summer than in spring because of the increase in organic matter in the chemical compositions of particles. In addition, NPF events introduced additional tiny fresh particles into the atmosphere, which reduced the κGf of 40-nm particles and increased the intensity of the less hygroscopic peaks (κGf < 0.1) of κ-probability density functions (κ-PDF) in NPF days. However, 100-nm particles exhibited fewer changes in κGf than 40-nm particles, resulting in additional dominant hygroscopic peaks (κ ∼ 0.2) of κ-PDFs in both NPF and non-NPF days. When κGf values measured in Seosan were compared with those in other Northeast Asian countries in the literature, the κ values for 40-nm particles were lower than those (κ > 0.2) measured in Beijing and Guangzhou, but those for 100-nm particles were close to those measured in the two cities.

Investigation of Icelandic Dust Presence in the Aerosols Collected at Hornsund (Svalbard, Norwegian Arctic) in Spring 2019

Investigation of Icelandic Dust Presence in the Aerosols Collected at Hornsund (Svalbard, Norwegian Arctic) in Spring 2019

Source-specified atmospheric age distribution of black carbon and its impact on optical properties over the Yangtze River Delta

Black carbon (BC) exerts a profound and intricate impact on both air quality and climate due to its high light absorption. However, the uncertainty in representing the absorption enhancement of BC in climate models leads to an increased range in the modeled aerosol climate effects. Changes in BC optical properties could result either from atmospheric aging processes or from variations in its sources. In this study, a source-age model for identifying emission sources and aging states presented by University of California at Davis/California Institute of Technology (UCD/CIT) was used to simulate the atmospheric age distribution of BC from different sources and to quantify its impact on the optical properties of BC-containing particles. The results indicate that regions with greater aged BC concentrations do not correspond to regions with higher BC emissions due to atmospheric transport. High concentrations of aged BC are found in northern Yangtze River Delta (YRD) regions during summer. The chemical compositions of particles from different sources and with different atmospheric ages differ significantly. BC and primary organic aerosols (POA) are dominating in Traffic-dominated source while other components dominate in Industry-dominated source. As the atmospheric age increases, the mass fraction of secondary inorganic aerosols rises. Compared to the original model, the simulated mass absorption cross section of BC particles in the source-age model decreases while the single scattering albedo increases. This compensates for ~11 % of the overestimation of the simulated BC direct radiative forcing. Our study highlights that incorporating atmospheric age and source information into models can greatly improve the estimation of optical properties of BC-containing particles and deepen our understanding of their climate effects.

Techno-economic feasibility and life cycle assessment analysis for a developed novel biosorbent-based arsenic bio-filter system.

Significant aquifers around the world is contaminated by arsenic (As), that is regarded as a serious inorganic pollution. In this study, a biosorbent-based bio-filter column has been developed using two different plant biomasses (Colocasia esculenta stems and Artocarpus heterophyllus seeds) to remove total As from the aqueous system. Due to its natural origin, affordability, adaptability, removal effectiveness, and possibility for integration with existing systems, the biosorbent-based bio-filter column presents an alluring and promising method. It offers a practical and eco-friendly way to lessen the damaging impacts of heavy metal contamination on ecosystems and public health. In this system, As (III) is oxidized to As (V) using chlorine as an oxidant, after this post-oxidized As-contaminated water is passed through the bio-filter column to receive As-free water (or below World Health Organization permissible limit for As in drinking water). Optimization of inlet flow rate, interference of co-existing anions and cations, and life cycle of the column were studied. The maximum removal percent of As was identified to be 500µgL-1 of initial concentration at a flow rate of 1.5 L h-1. Furthermore, the specifications of the biosorbent material was studied using elemental analysis and Zeta potential. The particle size distribution, morphological structures, and chemical composition before and after binding with As were studied using dynamic light scattering (DLS), scanning electron microscope-energy dispersive X-Ray spectroscopy (SEM-EDX), and fourier's transform infrared spectroscopy (FTIR) analysis, respectively. SuperPro 10 software was used to analyze the techno-economic viability of the complete unit and determine its ideal demand and potential. Life cycle assessment was studied to interpret the environmental impacts associated alongside the process system. Therefore, this bio-filtration system could have a potential application in rural, urban, and industrial sectors.

Characterization of Bulgarian Copper Mine Tailing as a Precursor for Obtaining Geopolymers.

Valorization of high-volume mine tailings could be achieved by the development of new geopolymers with a low CO2 footprint. Materials rich in aluminum and silicon with appropriate solubility in an alkaline medium can be used to obtain a geopolymer. This paper presents a study of copper mine tailings from Bulgaria as precursors for geopolymers. Particle size distribution, chemical and mineralogical composition, as well as alkaline reactivity, acidity and electroconductivity of aqueous slurry are studied. The heavy metal content and their mobility are studied by leaching tests. Sequential extraction was applied to determine the geochemical phase distribution of heavy metals. The studied samples were characterized by high alkalinity, which could favor the geopolymerization process. The water-soluble sulphates were less than 4%. The Si/Al ratio in mine tailing was found to be 3. The alkaline reactivity depended more so on the time of extraction than on the concentration of NaOH solution. The main part of the heavy metals was found in the residual fraction; hence, in high alkaline medium during the geopolymerization process, they will stay fixed. Thus, the obtained geopolymers could be expected to exert low environmental impact. The presented results revealed that studied copper mine tailing is a suitable precursor for geopolymerization.

Effect of Al–Fe–Mn–Si particle characteristics on the growth morphology and corrosion resistance of anodic oxide film on AA 3003 aluminium alloy

This study examines the impact of Al–Fe–Mn–Si particle characteristics in AA3003 alloy on the morphology and resistance of anodic oxide films against corrosion. The results show that low-silicon-content Al–Fe–Mn–Si particles oxidise simultaneously with the matrix to form a discontinuous porous oxide film, and complex small pores are formed in the porous layer; although high-silicon-content Al–Fe–Mn–Si particles have the same oxidation rate as the alloy matrix, the growth of the oxide film is hindered by unoxidised particles in the porous layer due to the influence of particle size and chemical composition, resulting in uneven growth of the oxide film and ultimately causing defects such as enlarged pores and cracks. A mechanism model for Al–Fe–Mn–Si particles affecting the morphology of oxide film growth was established. Electrochemical test results show that compared with the oxide film of the high-silicon-content alloy, the oxide film of the low-silicon-content alloy has better corrosion resistance performance, with a corrosion potential of −0.512V (compared with −0.836V for the high-silicon alloy) and a corrosion current density of 3.34 × 10−8A/cm2 (compared with 9.614 × 10−7 A/cm2 for high-silicon alloy). The barrier layer attained an elevated impedance value and exhibited self-repairing capabilities.

Production of filter material from various natural fibers

In this study, a composite filter paper was fabricated using cellulose derived from Flax and cotton linters, along with the incorporation of basalt fiber. The aim was to develop a filter paper with enhanced filtration performance and mechanical strength.The composition and properties of the mineral filler employed in the preparation of the filter paper were thoroughly investigated. The mineral filler, which played a crucial role in influencing the properties of the composite, was carefully selected and characterized. Its particle size, surface area, and chemical composition were analyzed to understand its impact on the filtration efficiency and mechanical integrity of the filter paper.To evaluate the performance of the composite filter paper, comprehensive testing methods were employed. The filtration efficiency, pressure drop across the filter, and mechanical strength properties such as tensile strength and burst strength were assessed. These tests provided quantitative data to determine the effectiveness of the composite filter paper in capturing particles of varying sizes and its structural stability during the experimental investigation were presented in graphical form to provide a clear visual representation of the data. These graphs allowed for easy interpretation and comparison of the properties and performance of the composite filter paper under different conditions.

Determination of composite fuel parameters in the operation of technogenic deposits of coal mining enterprises

The research provides the determining of the parameters for composite fuel in the operation of technogenic deposits at coal mining enterprises. The qualitative characteristics of technogenic raw materials are determined, and the parameters of technological processes to produce composite fuel are established: preparation (screening or grinding), physical and chemical influence on the state of raw materials, mixing, production, and drying (if necessary) to obtain suitable fuel. Based on the particle size distribution (as well as sedimentation analysis for waste fractions up to 50 μm) and chemical composition (with the determination of moisture, volatile matter, ash, and sulphur content) it was found that the physicochemical parameters for each type of industrial waste, when preparing them for use in the production of composite fuels, have been established. A technological classification of technogenic materials has been developed, which makes it possible to systematize technical issues in the implementation of preparation processes, physical and chemical influences, mixing, production, and drying to obtain suitable fuel.

A novel process for ultra-low emission of flue gas by adding waste heat steam

This work offers a new process for removing fine particles from converters by adding steam from a waste heat boiler. The fine particles were enlarged using the pre-technique of water vapor condensation which was initially validated its available in a lab-scale experimental system. Following the steam was introduced into the secondary scrubber system to reform converter dust removal system, the mass concentration of the dust at the stack outflow decreased from approximately 30 ∼ 40 mg/m3 to 6 mg/m3. The morphology and elemental content of the fine particles released from the chimney vents, with and without steam injection, were analyzed by SEM and EDS, respectively, to further investigate the particle size range and chemical composition of the fine particles eradicated by steam injection. It was discovered that the growth and removal of the 200–300 nm iron–rich fine particles can be facilitated by vapor condensation. This work provides a new idea for achieving ultra-low emission transformation of the converter wet dust removal process.