Morphology Composition Research Articles

Effects of surface morphology and chemical composition on friction properties of Xenopeltis hainanensis scales

The scales of Xenopeltis hainanensis, a snake that can crawl in fields, valleys, and other places, can serve as inspiration for the design of scale-like bionic materials. We present a systematic morphological, microstructural, chemical, and mechanical analysis, including elastic modulus, hardness, and wear morphology of the scales to understand the friction basis for achieving the reptile requirements. At the surface level, a comb-like arrangement of microstructures on the ventral scales provides more surface area and reduces pressure. The separation of microstructures, along with the bending and delamination of collagen fibrils could contribute to energy dissipation, which helps prevent catastrophic failure at deeper structural levels. At the cross-sectional level, a greater thickness provides more distribution of stresses over a larger volume, reducing local deformation and increasing the resistance to damage. At the material level, the ventral scales show higher modulus (E= 384.65 ± 19.03 MPa, H= 58.67 ± 6.15 MPa) than other regions of snake scales, which is attributed to the increased thickness of the scales and the higher concentration of sulfur (S). The experimental results, combined with Energy-dispersive X-ray spectroscopy and SEM characterization, provide a complete picture of the fiction properties influenced by surface morphology and chemical composition during scratch extension of the Xenopeltis hainanensis scales.

Silver Doped Polypyrrole Nanocomposite-based Gas sensor for Enhanced Ammonia Gas Sensing Performance at Room Temperature

Nanocomposite, which comprise organic and inorganic materials have gained increasing interest in the application for enhanced sensing response to both reducing and oxidation gases. In this study, a nanocomposite is chemical polymerization synthesized by reinforcing Ag nanoparticles with different concentration doped into the matrix of Polypyrrole (PPy). This nanocomposite is used as a sensing platform for ammonia detection with different concentration (ppm). The homogeneous distribution of Ag nanoparticles onto the PPy matrix provides a smooth and dense surface area, further accelerating the transmission of electrons. The synergistic effect of PPy@Ag matrix is responsible for the outstanding conductivity, compatibility and catalytic power of the proposed gas sensor. The structure, morphology, and surface composition of as-synthesized samples were respectively, examined via X-ray diffraction, field emission scanning electron microscopy, Ultraviolet-visible spectroscopy, Thermogravimetric analysis and Fourier transform infrared spectroscopy. The results indicated that sensor based on the PPy@Ag5 (2 gm) nanocomposite showed the highest response toward ammonia as compare to pure PPy at room temperature with a response value is 58 % to 100 ppm. Overall, the obtained findings demonstrated that the PPy@Ag nanocomposite are promising materials for gas sensing applications in environmental monitoring.

Exploring the role of edges in surface functionalization and stability of plasma-modified carbon materials: Experimental and DFT insights

Effective surface functionalization of carbon nanomaterials plays a crucial role in various applications. We investigated the impact of edges on surface functionalization and stability of oxygen-modified carbon materials using a combination of experimental techniques and Density Functional Theory (DFT) insights. Graphenic paper, highly oriented pyrolytic graphite (HOPG), and graphenic flakes were employed as model systems, with oxygen plasma treatment (generator power 100 W, oxygen pressure 0.2 mbar, exposure time 6 – 300 s) serving as the modification method. Surface morphology and chemical composition were characterized using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The results revealed the introduction of oxygen functional groups on the investigated carbon surfaces (up to 20 at % by XPS) whereas; the structural integrity of the materials remained intact upon plasma modification (SEM, Raman). Work function was used as a sensitive parameter for monitoring the surface changes (increase by ∼1.4 eV, 1.3 eV, and 1 eV for graphenic paper, HOPG, and graphenic flakes, respectively) while time-dependent measurements revealed distinct kinetic processes governing the decay of functionalization, highlighting the role of surface defects in post-plasma processes. DFT calculations provided molecular-level insights into the surface processes, elucidating the mechanisms underlying the diffusion of hydroxyls, their recombination, and water desorption. Since the calculated activation barrier for recombination on basal graphenic planes (∼1.0 eV) and edges (∼5.5 eV) are distinctly different, it can be thus concluded that the persistent functionalization is due to the surface edges. Our findings contribute to a deeper understanding of surface modification processes of carbon materials and offer rationales for the design of advanced functional nanomaterials with tailored surface properties.

Organoclays from acid-base activated vermiculites for oil-water mixture separations

Oily wastewater discharge causes severe environmental pollution and resource waste, requiring the development of low-cost adsorbents with good hydrophobicity. This study presents the preparation and use of a novel highly hydrophobic adsorbent based on natural vermiculite clay minerals to separate free/emulsified oil-water mixtures. Vermiculite was first activated with sulfuric acid and potassium hydroxide to increase its adsorption capacity and surface area. The sample was then modified with cetyltrimethylammonium bromide (CTAB) to change the wetting properties from hydrophilic to hydrophobic and increase oil adsorption. XRD, XRF, FESEM, BET, FTIR, and zeta potential analyses were carried out to determine changes in texture, morphology, and chemical composition of vermiculite affected by acid, base and acid-base activation. According to the results, the acid-base activation process was selected for vermiculite treatment before CTAB modification, which demonstrated a high oil adsorption selectivity (1910.6 %) compared to raw vermiculite (44.14 %). Effect of CTAB concentration on vermiculite's wetting properties was studied. The results confirmed that the acid-base activated sample modified at 0.9 mmol.L−1 near the critical micelle concentration of CTAB exhibited highly hydrophobic properties (water contact angle of 148° ± 1°). For oil-in-water emulsions, the treated adsorbent demonstrated a high oil removal efficiency of 96.4 %. Additionally, a packed layer of highly hydrophobic vermiculite was applied for free heavy/light oil-water mixture and water-in-oil emulsion separation. The performance test for separation of free oil-water mixture and water-in-oil emulsion showed high separation efficiency (all above 90 %). The reusability of highly hydrophobic vermiculite as well as the effect of oil type, the thickness of the adsorbent layer, and the height of the water phase on separation performance were also investigated.

Green superhydrophobic surface engineering of PET fabric for advanced water-solvent separation

This paper presents the preparation of the PET membrane for effective organic solvent separation achieved through an advanced superhydrophobic surface engineering of PET fabric utilizing biomimicry and a green chemistry approach. The superhydrophobicity of the PET surface was reached through a hierarchical nanocomposite coating that involved the integration of biomimetic polydopamine (PDA) coating, green-synthesized zinc oxide (ZnO) nanoparticles (NPs), and non-fluorinated quaternary ammonium cation silane (Si-QAC) coverage. The morphology and surface chemical composition of the resultant Si-QAC/ZnO/PDA@PET membrane were characterized by SEM, EDS, FT-IR, XRD, and AFM analysis. The surface topography and water contact angle were also correlated with surface roughness and its superhydrophobicity. The resulting Si-QAC/ZnO/PDA@PET membrane exhibited promising superhydrophobic properties, characterized by a water contact angle ranging from 150° to 160° and a roll-off angle between 5° and 2° as well as stability against severe conditions, including acidic and alkaline exposure, mechanical abrasion, and UV radiations. Moreover, the Si-QAC/ZnO/PDA@PET membrane exhibited bacterial repulsive properties against E. coli and Staphylococcus sp. The separation efficiency of various aliphatic and aromatic organic solvents (n-hexane, toluene, chloroform, and petroleum ether) from water higher than 90 % was also observed, making the membrane a potential candidate for different industrial applications, particularly for the separation of organic solvents from water.

ZnO/Zn3(PO4)2/CeO2 photocatalysts formed on zinc by plasma electrolytic oxidation

ZnO/Zn3(PO4)2 coatings doped with CeO2 particles for use in photocatalytic degradation of methyl orange (MO) were created by plasma electrolytic oxidation of zinc in a phosphate alkaline electrolyte (PAE) with CeO2 particle concentrations of up to 1.5 g/L. The CeO2 particle content in ZnO/Zn3(PO4)2 coatings was determined by the concentration of CeO2 particles in the PAE. Extensive research was conducted on coating morphology, chemical and phase compositions, and light-harvesting properties. The photocatalytic activity (PA) of ZnO/Zn3(PO4)2/CeO2 coatings was higher than ZnO/Zn3(PO4)2. The PA of ZnO/Zn3(PO4)2/CeO2 coatings strongly depends on the amount of CeO2 particles in PAE, and the highest PA was observed for ZnO/Zn3(PO4)2/CeO2 coating formed in PAE by adding 0.75 g/L of CeO2 particles. The higher PA of ZnO/Zn3(PO4)2/CeO2 compared to ZnO/Zn3(PO4)2 is due to a lower photogenerated electron/hole recombination. The photocatalytic degradation of MO followed a pseudo-first order kinetic model and the reaction constant of the most photoactive ZnO/Zn3(PO4)2/CeO2 coating was increased about twofold compared to the ZnO/Zn3(PO4)2 coating. After 6 hours of irradiation, the PA for ZnO/Zn3(PO4)2 and the most photocatalytically active ZnO/Zn3(PO4)2/CeO2 was about 70% and 98%, respectively. A mechanism for the photodegradation of MO with the ZnO/Zn3(PO4)2/CeO2 photocatalyst was also proposed.

Biosynthesis; Characterization; and Antibacterial, Antioxidant, and Docking Potentials of Doped Silver Nanoparticles Synthesized from Pine Needle Leaf Extract

The current study focused on the synthesis of doped silver nanoparticles (doped AgNPs) with yttrium (Y), gadolinium (Gd), and chromium (Cr) from pine needle leaf extract (PNLE). X-ray diffraction (XRD) was performed to assess the phase formation, detecting 61.83% from Ag and 38.17% for secondary phases of AgCl, AgO, Y, Cr-, and Gd phases. The size and shape of the NPs were determined by transmission electron microscopy (TEM), showing a spherical shape with an average particle size of 26.43 nm. X-ray photoelectron spectroscopy (XPS) detected the oxidation state of the presented elements. The scanning electron microscope (SEM) and the energy-dispersive X-ray analysis (EDX) determined the morphology and elemental composition of the NPs, respectively. Fourier transform infrared spectroscopy (FTIR) determined the different functional groups indicating the presence of Ag, Y, Gd, Cr, and other groups. Photoluminescence (PL) spectroscopy showed the optical properties of the NPs. A vibrating sample magnetometer (VSM) revealed the ferromagnetic behavior of the doped AgNPs. The antibacterial activity of the doped AgNPs was tested against six uro-pathogenic bacteria (Staphylococcus aureus, Staphylococcus haemolyticus, Enterococcus faecalis, Escherichia coli, Klebsiella pneumonia, and Pseudomonas aeruginosa) using the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) microdilution assays, agar well diffusion assay, time–kill test, and antibiofilm screening assays, revealing significant activity, with MICs ranging between 0.0625 and 0.5 mg/mL and antibiofilm activity between 40 and 85%. The antioxidant activity was determined by the 1,1, diphenyl 1-2 picrylhydrazyl (DPPH) radical scavenging assay with a potential of 61.3%. The docking studies showed that the doped AgNPs had the potential to predict the inhibition of crucial enzymes such as penicillin-binding proteins, LasR-binding proteins, carbapenemase, DNA gyrase, and dihydropteroate synthase. The results suggest that the doped AgNPs can be applied in different medical domains.

Investigation of the Influence of Structure, Stoichiometry, and Synthesis Temperature on the Optical Properties of CdTe Nanoplatelets

Colloidal cadmium telluride (CdTe) nanoplatelets (NPLs) are promising materials for optoelectronic applications, such as photovoltaics and light-emitting diodes, due to their unique optical and electronic properties. However, controlling their growth, thickness, and stoichiometry remains challenging. This study explores the effect of synthesis temperature on the structural, optical, and stoichiometric properties of CdTe NPLs. CdTe NPLs were synthesized at temperatures of 170 °C, 180 °C, 190 °C, and 200 °C using colloidal methods. The resulting NPLs were characterized by UV–Vis absorption spectroscopy, photoluminescence (PL) spectroscopy, transmission electron microscopy (TEM), and total reflection X-ray fluorescence (TXRF) to assess their morphology, structure, and elemental composition. The results showed that the synthesis temperature significantly affected the NPL’s morphology and stoichiometry. Optimal stoichiometry was achieved at 180 °C and 190 °C, with the crystal structure transitioning from zinc blende at lower temperatures to wurtzite at higher temperatures. Optical properties, including luminescence intensity and emission peaks, also varied with temperature. The synthesis temperature is an important parameter in controlling the structural and optical properties of CdTe NPLs. The optimal conditions for obtaining NPLs with the best characteristics were identified at 190 °C, presenting important findings for further optimization of CdTe NPL synthesis for optoelectronic applications.

Water desalination using atmospheric pressure plasma combined with thermal treatment

AbstractHerein, a novel method is presented for enhancing the thermal desalination process of saline water and seawater using atmospheric pressure plasma (APP). The effect of APP treatment combined with thermal heating (APP-TH) on the energy consumption, conductivity, and pH of seawater and saline water is investigated. Utilizing scanning electron microscopy and X-ray diffractometry, the evolution of the morphology, structure, and chemical composition of precipitated crystals is characterized. The APP-TH method reduces the energy consumption for desalination by 40.5% for saline water and by 52.82% for seawater when compared to the TH-only method. The pH value remains approximately unchanged, decreasing slightly for the saline water from 7.1 for untreated saline water to 7.05 after APP-TH treatment. However, after APP-TH treatment, the pH value of the seawater increased slightly, from 7 to 7.8. The total dissolved salts decreased after APP-TH treatment, lowering the conductivity of the saline water from 65,000 µS/cm to 160 µS/cm and the conductivity of the seawater from 58,200 µS/cm to 243 µS/cm. Moreover, the size of precipitated crystals from saline water is 31.47 nm after APP-TH treatment, compared to 55.59 nm after TH-only treatment. They also dropped from 41 nm to 39.5 nm for seawater. Compared with traditional approaches, this research proposes an optimistic solution to address global potable water scarcity issues.

Solvothermal Synthesis of Medium-Entropy Oxide Spheres for Thermocatalytic Conversion of CO2 to Methanol.

New chemical compositions and structures for medium- and high-entropy oxides (HEOs) currently represent a promising new avenue in materials research for a wide range of applications including catalysis, energy storage, and ceramics. To speed up further development, synthesis methods for multicationic oxides are needed for controlling features like morphology, porosity, and chemical compositions. In this work, mesoporous spinel oxide spheres with five cations are synthesized using solvothermal synthesis techniques. The targeted chemistry included Co, Al, Fe, and Cr as the first four cations, where the fifth cation was varied by increasing cation radii (Ga, In, Yb, Ho, or Ce). After calcination, all as-synthesized precursors led to mesoporous oxide spheres with spinel oxide structures. In order to demonstrate an example of applicability for targeting different M3+ cations, the sample containing Co, Al, Fe, Cr, and In was tested in a model reaction of thermocatalytic CO2 hydrogenation and is shown to be active with a preference to methanol formation (58% selectivity, 7.8% conversion at 300 °C). The synthesis of multicationic mesoporous spheres appears to be quite flexible in terms of possible M3+ cations compositions and is a potential material to combine targeted chemistry for applications like catalysis.

Effect of annealing conditions on resistive switching in hafnium oxide-based MIM devices for low-power RRAM

Abstract This work presents resistive switching (RS) behaviour in HfO2-based low-power resistive random-access memory (RRAM) devices. A metal-insulator-metal (MIM) structure (Au/HfO2/Pt) was fabricated by sandwiching a thin insulating layer of HfO2 between Pt and Au electrodes. HfO2 films deposited by RF sputtering at room temperature were rapid thermally annealed in N2 ambient at 400 °C and 500 °C. Grazing angle x-ray diffraction (GIXRD), Field emission gun-scanning electron microscopy (FEG-SEM), atomic force microscopy (AFM), and x-ray photoelectron spectroscopy (XPS) were employed to analyse the phase, crystal structure, morphology, surface roughness and chemical composition of the HfO2 films. The bipolar RS could be observed in both as-deposited and annealed HfO2 film-based devices from I–V characteristics measured using a source meter. We have investigated the effect of annealing temperature and annealing ambient on the phase formation of HfO2 as well as the RS characteristics and compared with as-deposited film-based device. Annealed HfO2 film-based devices exhibited improved electrical characteristics, including stable and repeatable RS at significantly lower switching voltages (<1 V) which indicates low power consumption in these devices. The relatively lower processing temperature of the HfO2 films and that too in the films deposited by physical vapor deposition (PVD) technique-RF magnetron sputtering makes this study significantly useful for resistive switching based non-volatile memories.

Adsorption of Arsenic and Cadmium on Biodegradable and Non-Biodegradable Microplastics in Soil: Comparison Based on Batch Experiment

In the present study, the adsorption of arsenic(V) and cadmium(II) onto microplastics from poly(butylene succinate-co-butylene adipate) (PBSA) and low-density polyethylene (LDPE) plastic mulch films was investigated through batch experiment. The surface morphology and elemental composition of soil and microplastics were analyzed with scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy (SEM-EDX) and Fourier-transform infrared (FTIR) spectroscopy. The results show that the adsorption of As(V) and Cd(II) on microplastics led to surfaces with coarseness and more cracks, and many small particles. Under the conditions added with 100 pieces of microplastic, PBSA enhanced the adsorption capacity of As(V) (from 0.43 to 0.49 mg/g), and LDPE increased the adsorption of Cd(II) (from 0.174 to 0.176 mg/g) due to the “superimposed effect” caused by hydrogen bonds. Conversely, LDPE reduced the adsorption of As(V) (from 0.44 to 0.40 mg/g) due to a “dilution effect” of PE. Particularly, PBSA exhibited an insignificant effect on the adsorption of Cd(II) in soil during the present study. Overall, our findings provide new insights into the impacts of microplastics on the fate and behavior of heavy metals in the soil system.

Effect of agitation during the early-age hydration on thixotropy and morphology of cement paste

AbstractThe effect of agitation during the early-age hydration on thixotropy and morphology of cement paste prepared with and without superplasticizers (SP) is investigated by applying penetration test, small amplitude oscillatory shear sweep test (SAOS), isothermal calorimetric test, scanning electron microscopy (SEM) and energy dispersive X-ray analyses (EDX). The results show that the agitation of cement paste during the induction period increases the heat flow rate and destroys existing structures of samples without changing the mineral composition of samples. Yet, if the agitation is applied during the acceleration period, the heat flow rate is significantly lowered and the morphology and mineral composition of samples undergo irreversible change, freshly formed syngenite is destroyed and no longer restored. The penetration force and the static yield stress grow linearly during the induction period and exponentially during the acceleration period. Agitation during the induction period destroys the structure, which causes the static yield stress and the penetration force values becoming nearly equal to zero. However, during the acceleration period, even after agitation the static yield stress and the penetration force exhibit high residual values, which indicates the impact of hydration to the structural build-up.

Morphological and agronomic evaluation of short-cycle native maize varieties (Zea mays L.)

Objective: The objective of this study was to analyze the morphological composition and agronomic behavior of five varieties of Zea mays L. Two Zapalote Chico, two Zapalote Grande and an improved variety (V-424) which are characterized by having a short vegetative cycle Desing/methodology/approach: The maize varieties evaluated were sourced from various locations within the municipality, with explicit consent from the producers, who provided the seeds for the study. Four native cultivars (treatments) were selected from the Zapalote Chico and Zapalote Grande races and one improved and open-pollinated maize variety (V-424 or Tuxpeño Precoz) as a control, released by INIFAP. The local farmers assigned the common names to the evaluated maize varieties, except for V-424. The varieties were distributed in a randomized block design with four replications, resulting in a total of 20 experimental units. Each unit consisted of four furrows, each measuring 4 meters in length. Results: The findings of this study on native short-cycle maize varieties in Chiapas have significant implications at the genetic, social, cultural, economic, and environmental levels. Each of these aspects provides crucial guidance for decision-making related to the utilization, management, and conservation of local maize varieties. A key outcome of this study is the recognition of native maize as a repository of essential genes for food security in rural areas. Short-cycle landraces exhibit unique genetic adaptations that enable them to thrive under the specific agroclimatic conditions of the Frailesca region in Chiapas. Limitations on study/implications: none Findings/conclusions: The native maize varieties exhibited significant genetic variability across the variables under consideration. The Zapalote Chico race is characterized by its favourable characteristics, as recognized by farmers, including early maturity, drought resistance, lodging resistance, and resistance to the fall armyworm. These qualities make it a promising candidate for future research and for inclusion in genetic improvement programs, whether conventional or participatory. It is crucial to continue promoting agroecological inputs with the goal of fostering the development of resilient agroecosystems and, consequently, enhancing the well-being of farmers and the conservation of native maize reservoirs.

Study on morphology, biological activities, and chemical compositions of Oenanthe javanica (Blume) DC. essential oil

Study on morphology, biological activities, and chemical compositions of Oenanthe javanica (Blume) DC. essential oil

NGC 6826- Integrated Study of the Planetary Nebula and Central Star Properties

This study provides a comprehensive analysis of NGC 6826, focusing on the structural, kinematic, and spectroscopic properties of its planetary nebula and the characteristics of its central star. By integrating multi- wavelength observational data, we examine the nebular morphology, ionization structure, and chemical composition, which reveal insights into the evolutionary processes shaping the nebula. Additionally, we analyze the central star’s luminosity, temperature, and spectral features to understand its role in driving the observed nebular dynamics. Our findings contribute to the broader understanding of planetary nebula formation, central star evolution, and the interaction mechanisms at play. This integrated approach underscores the importance of studying planetary nebulae in a holistic context to unravel the complexities of stellar evolution. Keywords: NGC 6826, planetary nebula, central star, kinematics, stellar evolution, spectroscopy

Synthesis and Characterization of Thymol Carbon Nanodot Functionalized Silver Nanoparticles (ThCND-AgNPs) and Evaluation of Their Antiproliferative, Anti-Invasive, and Apoptotic Effects on OVCAR-3 Ovarian Cancer Cells.

Ovarian cancer belongs to the category of gynecological malignancies and unfortunately holds the distinction of being the most aggressive among them. It is ranked as the fifth highest cause of cancer-related deaths in women worldwide. The utilization of metal nanoparticles (NPs) linked with natural herbal molecules in biomedical applications has been on the rise. Thymol carbon nanodot functionalized silver nanoparticles (ThCND-AgNPs) were synthesized in an original manner and subjected to thorough characterization, including analysis of their size, morphology, and elemental composition. The aim of this study is to investigate the effects of the ThCND-AgNPs on cell proliferation, invasion, and apoptotic gene expressions in OVCAR-3 ovarian cancer cells. The effect of ThCND-AgNPs on cell viability in OVCAR cells was determined in a dose- and time-dependent manner using the XTT method. The effect on the expression changes of apoptotic-related genes was assessed through the Real-time PCR method, while the anti-invasive activity was measured using the matrigel invasion chamber assay. The ThCND-AgNP molecule exhibited a dose- and time-dependent reduction in cell proliferation in OVCAR-3 cells. The IC50 values were determined to be 388.53 μg/mL at 24 h and 145.683 μg/mL at 48 h. Furthermore, the molecule was found to reduce cell invasion by 51.12% compared with the control group in OVCAR-3 cells. In terms of apoptotic-related genes, Bcl-2 expression was downregulated, while BAX, CASPASE-3, -8, and -9 expressions were unregulated. In conclusion, the obtained data reveal the potential antiproliferative, apoptotic, and anti-invasive effects of our original ThCND-AgNP molecule in ovarian cancer. While these results need further confirmation through more detailed experiments, they will provide insights for future studies.

Characterization of Chemical Information and Content Prediction of Dendrobium officinale Based on ATR‐FTIR

ABSTRACTDendrobium officinale is a medicinal and food plant with high commercial and medicinal value. Yunnan is known as China's “plant kingdom,” and although the climatic conditions are favorable, the large vertical climatic differences have led to a large difference in the quality of dendrobium from different origins. The analysis of quality differences between several origins with large ecological advantages has not been reported yet. Therefore, the aim of this study is to compare these regions in terms of both morphology and chemical composition and to analyze the variation of their chemical composition in spectral information. The PLS‐DA, SVM, and PLSR models were developed to qualitatively and quantitatively evaluate Dendrobium from different production areas. The results show that the Menghai production area was superior to other production areas in terms of phenotypic morphology, quality, and yield. Within the appropriate range, the higher the specific absorbance, the higher the quercetin content.

Observing super-coarse carbonaceous aerosol particles containing chloride in a tropical savanna climate at an agro-forest site in Thailand.

Coarse aerosol particles containing chloride in tropical forests are significant for understanding biogeochemical cycles and atmospheric processes, with implications for environmental health and climate change mitigation. This study explored the sources of super-coarse carbonaceous aerosol particles containing chloride in a tropical savanna climate. Aerosol samples were collected from an agro-forest site in Thailand during the dry season and analyzed using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and Fourier-transform infrared (FTIR) spectroscopy. By examining the morphology and elemental compositions of individual aerosol particles, along with employing Positive Matrix Factorization (PMF) and backward trajectory analysis, potential sources were identified. The findings revealed two primary sources for the super-coarse aerosol particles: a mixture of biomass burning smoke and inorganic salts (likely from saline soil and sea salt), as well as halophilic fungal spores. FTIR analysis indicated the presence of compounds linked to biomass burning and clay minerals, influenced by prevailing northeast and southeast winds. Recommendations for future research include continued monitoring, correlation with meteorological parameters, and the application of transmission electron microscopy (TEM) for more detailed visualization and confirmation of aerosol sources.

Analyzing Morphology and Composition of Coarse Aerosol Particles in Bangkok, Thailand: Implications to Sources and Impacts of Aged Aerosols on Ecosystem Health and Climate Dynamics

AbstractDuring dry seasons, elevated aerosol levels across Thailand pose nationwide problems. Understanding and addressing this issue is challenging due to the dynamic nature of aerosol modification and generation during transport. This study investigates the morphology and elemental compositions of coarse aerosol particles in Bangkok, Thailand, during the dry seasons of 2020/21. Through scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectrometry (EDS), the study reveals a complex mixture of anthropogenic, mineral, biogenic, and marine aerosols. Anthropogenic sources, including biomass burning, vehicular emissions, and industrial activities, contribute to carbonaceous particles like soot aggregates and tar balls. Mineral dust particles, predominantly calcium-rich and aluminosilicate, originate from various sources including construction, industry, and natural processes. Aging processes alter the composition and properties of both carbonaceous and mineral particles, influencing nutrient deposition, carbon sequestration, cloud condensation nuclei formation, and light scattering. These processes have multifaceted impacts on ecosystem health and climate dynamics, highlighting the need for further research and mitigation strategies to address the environmental consequences of aged aerosol particles in urban environments like Bangkok.