Scanning Electron Microscopy With Energy Dispersive X-ray Research Articles

Characterization of Respirable Coal Mine Dust Recovered from Fibrous Polyvinyl Chloride Filters by Scanning Electron Microscopy

AbstractThe characterization of respirable dust on the basis of constituent fractions and particle sizes is increasingly of concern for evaluating exposure hazards. For high-resolution particle analysis, scanning electron microscopy with energy dispersive X-ray (SEM-EDX) can be an effective tool. However, it requires particles to be deposited on a smooth, uniform substrate such as a polycarbonate (PC) filter for optimal results. While direct sampling onto PC is possible, this is not the standard approach in many situations. For example, in coal mines, respirable dust samples have typically been collected onto polyvinyl chloride (PVC) filters because they are intended for gravimetric and/or infrared spectroscopy analysis. Such fibrous substrates are not ideal for SEM-EDX (or other microscopy), but an effective method to recover and redeposit the dust particles could render such samples suitable for the additional analysis. Here, we present a simple method and compare SEM-EDX results for paired samples analyzed directly on PC and following recovery from PVC and redeposition on PC. Both laboratory-generated dust samples (n = 10 pairs) and field samples of respirable coal mine dust (n = 44 pairs) are included in this study. Although some changes in particle size distributions were observed between samples analyzed directly and those that were recovered and redeposited prior to analysis, the results indicate the dust recovery method generally yields a representative sample in terms of mineral constituents. That said, results also highlighted the effects of high particle loading density on individual particle analysis. Considering all sample pairs, those with similar loading density between the directly analyzed and recovered sample tended to exhibit similar mineralogy distributions. This was generally the case for the lab-generated sample pairs, and the Freeman-Halton exact test of independence indicated that the samples in just three (of 10) pairs were in disagreement in terms of their mineralogy distributions. On the other hand, for the field samples, the directly analyzed sample often had higher loading density than the recovered sample; and the Freeman-Halton test showed that 25 (of 44) pairs were in disagreement. However, the effect of possible particle agglomeration on the directly analyzed samples cannot be ruled out—and exploration of this factor was beyond the scope of the current study.

Consecutive high-performance removal of Cu2+ metal ions and Deltamethrin using multifunctional pyrolysis cuttlebone/cotton fabric nanocomposite

A simple technique was developed for the modification of cotton materials that is inexpensive, environmentally friendly, and very effective. Waste Cotton fabrics (WCFs) are loaded with propolis extract (PE) for Cu2+ removal. Then, Cu2+ underwent a pyrolysis process with modified cuttlebone (CB) at 900 °C for 5 h. The surface of the prepared materials was characterized using X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray (SEM-EDX), Fourier transform infrared (FTIR), BET, particle sizes, thermogravimetric analysis (TGA) and zeta potential analysis. The Cu2+ metal ions from an aqueous solution were removed using WCFs/PE, and DLM was subsequently removed using pyro WCFs/PE/Cu/CB. The as-prepared NPs exhibited the face-centered cubic structure of WCFs/PE/Cu/CB with crystallite sizes ranging from 386.70 to 653.10 nm. FTIR spectra revealed that CB was present on the surface of the resulting WCFs/PE/Cu. SEM revealed the dispersion of a uniformly flower-like morphology over a large area. Sorption studies were performed based on parameters that included pH, dose, contact time, and initial concentration. The adsorption isotherm and the kinetic studies of the DLM adsorption process were applied at a pH of 5.0 and a temperature of 25 °C using several isotherms and kinetic models. The results revealed qmax (20.51 mg/g) with R2 = 0.97, the Langmuir isotherm that best matches the experimental data. Hence, the Langmuir isotherm suggests that it is the model that best describes sorption on homogenous surfaces or surface-supporting sites with various affinities. The correlation coefficient R2, χ2, adjusted correlation coefficient, and error functions like root mean square (RMSE), normalized root mean square error (NRMES), and mean absolute error (MAE) were used to evaluate the best-fit models to the experimental adsorption data. Moreover, cost estimation for the prepared adsorbent WCFs/PE/Cu showed that it costs approximately 3 USD/g, which is a cheap adsorbent compared to other similar adsorbents reported in the literature. The examined WCFs/PE have significant applicability potential for Cu2+-laden wastewater treatment due to their superior Cu2+ metal ions adsorption capability and reusability.The cytotoxicity and safety study showed that at higher concentrations, it resulted in much less cell viability. Additionally, the removal efficiency of Cu2+ metal ions from synthetic, realistic industrial wastewater using WCFs/PE reached up to 96.29 %, demonstrating good adsorption capability. Thus, there is a huge possibility of accomplishing this and performing well. This study paves the way for the reuse and valorization of selected adsorbents following circular economy principles.Two green metrics were applied, the Analytical Eco-scale and the Analytical GREEnness Calculator (AGREE).

Colorimetric Barium Detection of Gunshot Residues on Cadaveric Human Skin: A Pilot Application for Forensic Purposes.

In this study we microscopically investigated, for the first time ever, the colorimetric detectability of barium of gunshot residues (GSR) on cadaveric human skin with gunshot wounds. For this purpose we used two different colorimetric techniques known in the literature, namely 0.2% sodium rhodizonate (Na-R-Ba 0.2%) and sodium rhodizonate in alcoholic environment (Na-R-Ba OH 0.2%). At the same time, we have also coupled it with scanning electron microscopy with energy dispersive X-ray (SEM/EDX) analysis and the colorimetric study for the detection of lead of GSR. These techniques were applied to 16 victims who died from gunshot injuries, as well as to a control group. SEM/EDX demonstrated the presence of lead in all cases and barium in 11 of the 16 cases. The subsequent colorimetric technique with Na-R-Ba 0.2% did not show the barium of GSR in any case, unlike the Na-R-Ba OH 0.2% technique. This latter, in fact, has demonstrated the presence of this metal in 2 cases (18%). No microscopic case of false positive was recorded. The evidence obtained with Na-R-Ba OH 0.2% makes this method, applied here for the first time ever, worthy of further study. Meanwhile, although this technique can certainly be applied, it cannot be separated from the contextual colorimetric investigation for lead and the use of more sophisticated techniques.

Photodegradation of Phenol under Visible Light Irradiation Using Cu-N-codoped ZrTiO<sub>4</sub> Composite as a High-Performance Photocatalyst

Codoping of nitrogen and copper into zirconium titanate composite (Cu-N-codoped ZrTiO4) was carried out through a sol-gel process. This study aimed to investigate the effect of copper and nitrogen dopants on the photocatalytic activity of ZrTiO4 composite in degrading phenol. To prepare the composite, an aqueous suspension of zirconia (ZrO2) alongside a fixed amount of urea and various amount of copper sulfate was added dropwise into diluted titanium(IV) tetraisopropoxide (TTIP) in ethanol. The composites were calcined at temperatures of 500, 700, and 900 °C. Fourier-transform infrared spectrophotometry (FTIR), X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray (SEM-EDX) mapping, and specular reflectance UV-visible spectrophotometry (SR UV-vis) were used for their characterization of composite. The photocatalytic activity was evaluated by adding the composite into a 10 mg L−1 phenol solution for various irradiation time spans. The remaining concentration of phenol solution was determined by absorption at 269 nm. Cu-N-codoped ZrTiO4 composite containing 5% Cu calcined at 500 °C demonstrated the highest observed rate constant and a significant band gap decrease from 3.13 to 2.68 eV.

Mechanical Behavior and Microstructure Evaluation of Quicklime-Activated Cement Kiln Dust-Slag Binder Pastes.

Cement kiln dust (CKD) is a by-product of cement production, which has the shortcomings of low utilization and high-temperature activation. This study combined CKD and slag as precursors for preparing pastes through quicklime activation under ambient conditions. The effects of quicklime and CKD content on the workability (flowability and setting time), macro-mechanical properties, and micro-structure of the CKD-slag binders were analyzed. The experimental results showed that the rapid precipitation of Ca2+, Si4+, and Al3+ ions from the CKD provided more nucleation sites for the formation of calcium aluminosilicate hydrate (C-(A)-S-H) gel and enhanced the reactivity of the binder system under the influence of the activator (CaO). The specimens had the highest unconfined compressive strength (UCS) (24.6 MPa) after 28 days with 10% quicklime content and 60% CKD content; scanning electron microscopy with energy-dispersive X-ray (SEM-EDX) analysis showed that the Ca/Si ratio of the C-(A)-S-H gel was minimized, leading to a denser microstructure and better binding ability under this mixing proportion. Therefore, this study may provide novel binder materials with a high proportion of CKD under ambient conditions.

Electrocatalytic performance of Shape-Controlled synthesized PdNi-rGO nano Cube on sodium borohydride and methanol electrooxidation

In recent years, increasing climate change, environmental pollution and water problems have increased the need for sustainable and environmentally friendly solutions in energy production. In this context, renewable energy sources, especially fuel cells, have become an important focus. In this study, the synthesis and characterization of the shape-controlled synthesized PdNi-rGO Cube electrocatalyst was carried out. X-ray diffraction (XRD), scanning electron microscopy with energy dispersive x-ray (SEM-EDX), and transmission electron microscope (TEM) characterization experiments were performed to examine the shape of the particles. TEM analysis revealed the formation of nanostructures with a size of 19.18 nm in the cubic structure of the PdNi-rGO. Furthermore, cyclic voltammetry (CV) measurements evaluated the usability of this electrocatalyst in the electrooxidation of sodium borohydride (NaBH4), and methanol (CH3OH). In this context, the anodic peak current density values were 77.34 mA/cm2 and 13.47 mA/cm2, for electrooxidation of sodium borohydride (NaBH4), and methanol (CH3OH), respectively. This study demonstrates that PdNi-rGO cube contains shape-controlled nanostructure, and these structures can play an important role in future renewable energy sources. It can also be considered an important step forward in the development of nanomaterial-based electrocatalysts capable of efficient energy conversion.

Characterisation of Water Treatment Sludge (WTS) at a Water Treatment Plant in Melaka

Water treatment sludge (WTS) is a by-product produced in the process of water treatment plants (WTP). It is estimated that an ordinary WTP produces over 10,000 tonnes of WTS per day, which has become a major concern in the management of WTS. Numerous previous studies have been accomplished to determine a safe disposal method and the potential reuse of WTS. In most investigations, material characterisation was the adopted method. It is known that each WTP produces different chemical composition of WTS according to raw water intake and the treatment process. The aim of this paper is to examine the chemical composition of WTS in the WTP at Melaka. The WTS sample is collected from WTP after the pressing process, where large amounts of water have been removed. The sample is tested using the Scanning Electron Microscopy with energy dispersive X-ray (SEM-EDX) and X-ray Diffraction (XRD). The SEM-EDX results revealed that by weight percentage (%), WTS contains zirconium (Zr) (28 to 46%), oxygen (28 to 40%) and carbon (7 to 26%). Aluminium and silicon have weight percentages ranging from 7 to 8%. The outcomes are then confirmed by XRD, which showed the high intensity of Zr and α-Zr at approximately 35.3 and 36.1. of 2θ. Based on these findings, the suitable and potential reuse of WTS would be the extraction of Zr. However, further research is required to verify the consistency of Zr in WTS.

Identification and analysis of gemstone binding materials on imperial rank belts excavated from the tomb of Murongzhi

AbstractThis paper analyzes and identifies the binders used in the jewel settings of the Baodian and Diexie belts excavated from the tomb of Murongzhi in Wuwei, Gansu, China. Fourier transform infrared spectroscopy (FTIR) indicated the presence of protein in the binder samples. The result of gas chromatography–mass spectrometry (GC‐MS) shows that samples from both contained hydroxyproline, a characteristic amino acid for animal glue. Principal component analysis was performed on one of the samples, and it was concluded that the binder was a mixture of hide glue and egg glue. Further analysis using scanning electron microscopy with energy‐dispersive X‐ray (SEM‐EDX) and laser Raman spectroscopy (Raman) found that a red particulate matter visually identified in the binder was cinnabar, which was apparently added to binder in order to modify the color of the jewels. This study provides a basis for the conservation and restoration of future finds of elite jewelry. It also shows how imperial jewelry was made during the Tang Dynasty. Finally, the analysis of these heraldic belts provides a key insight the life and role of an exiled prince in the Tang court.

Characterization of sago tree parts from Sentani, Papua, Indonesia for biomass energy utilization

Biomass derived from organic waste in industrial processes is an effective method to mitigate the negative impacts of agricultural waste materials. In Sentani, Papua, one such potential biomass source is sago tree waste. This study characterized the waste from the bark, middle, and inner parts of the sago tree to evaluate its biomass energy potential. Scanning electron microscopy with energy-dispersive X-ray (SEM-EDX) analysis of the complete sample revealed that oxygen, carbon, and silicon were the primary elements, with carbon content ranging from 30.75 % to 38.87 %. This indicates that all parts of the sago plant have the potential to be used as biomass fuel. Thermogravimetric analysis (TGA) results showed that the inner section of the sago had the lowest moisture content at approximately 13.3 %, followed by the outer part at 42 % and the bark at 55 %. The inner section had the highest lignin content, approximately 37 %, and exhibited the slowest thermal degradation in the differential thermal analysis (DTA) profile. The outer and bark parts of the sago were more reactive in stage II of the DTA profile, suggesting a higher concentration of cellulose and hemicellulose compared to lignin, making them suitable for gasification and pyrolysis. The heating value of sago bark was determined to be 12.85 MJ/kg (adb). These findings underscore the potential of sago waste as a renewable energy source, particularly in remote areas.

Preparation of magnetic surface molecularly imprinting polymers based on glycidyl methacrylate as selective sorbents for aniline removal from aqueous medium

In this paper, two molecularly imprinted polymers (MIPs) based on glycidyl methacrylate were synthesized by radical suspension polymerization and surface imprinting method in the presence of silica-coated magnetic nanoparticles. Ethylenediamine (eda) and triethylentetramine (teta) were used for surface imprinting. The samples were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), and mercury porosimetry. The sorption and desorption behaviors of two MIPs as an aniline sorbent from aqueous solutions were evaluated. Sorption studies were carried out in the pH range of 2.0 - 10.0, and maximum sorption capacities were attained at pH 6.0. Also, the effect of different desorption agents were examined and acetonitrile was chosen as the best desorbing eluent for aniline. The obtained MIPs were regenerated in four sorption/desorption cycles, and the results show that these two MIPs could be reusable as sorbents for removing aniline from polluted wastewater.

Performance Evaluation of Various Filter Media for Multi-Functional Purposes to Urban Constructed Wetlands

The escalating demand for innovative solutions is driven by the challenges posed by water quality degradation and the pervasive impacts of climate change. As such, this study evaluated the performance of filter media to mitigate these challenges through multi-functional applications in urban constructed wetlands (UCWs). Column testing of organic filter media, including biochar (BC), woodchip (WC), anthracite (AT), and activated carbon (AC), as well as inorganic filter media, such as ceramic balls (CB), basalt (BS), and porous sand (PS), with synthetic stormwater runoff influent was conducted to assess their performance through water quality parameters and Scanning Electron Microscopy with Energy Dispersive X-ray (SEM-EDX) analysis for carbon storage potential. Among the media tested, AC exhibited high pollutant removal efficiencies amounting to 84%, 54%, 56%, and 44% for total suspended solids (TSS), chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP), respectively. For inorganic media, PS had the highest TSS and TN removal, whereas BS exhibited the highest COD and TP removal. Overall performance rating revealed that AC and BS, despite their efficient pollutant removal, are associated with higher costs, resulting in a lower ranking compared to AT and PS. SEM-EDX analysis identified PS and AC as standout media for potential carbon storage, attributed to their extensive surface areas and pore structures providing abundant adsorption sites. The results from this study highlighted the potential applications of various filter media in UCW designs with the aim of achieving carbon neutrality and sustainable urban development.

Response surface methodology optimization of electrode modification parameters toward hydrazine electrooxidation on Pd/MWCNT/GCE

In this study, MWCNT supported Pd (Pd/MWCNT) was synthesized by NaBH4 reduction method as catalyst for hydrazine electrooxidation reaction (HEOR). Characterization methods namely inductively coupled plasma mass spectrometry (ICP-MS), elemental mapping, and scanning electron microscopy with energy dispersive X-ray (SEM-EDX) were used to analyze the surface morphology and metal composition of the catalysts. The Pd/MWCNT catalyst's average particle size is estimated to be 6.35 nm based on SEM images. Glassy carbon electrode (GCE) modification parameters namely the amount of catalyst ink transferred to the GCE surface (Vs), ultrasonication time of the catalyst ink (tu), and the drying time of the Pd/MWCNT/GCE (td) were optimized by using response surface methodology as 4.92 μL, 1 min and 19.52 min, respectively. Experimental specific activity value for HEOR was obtained as 7.13 mA cm-2 with 2.59% deviation under optimum conditions. Optimization of electrode preparation conditions is an inexpensive and facile method that could be used to improve the performance of anode catalysts for fuel cells.

A MULTI-ANALYTICAL STUDY OF BUILDING MATERIALS AND DETERIORATION PRODUCTS OF THE ROYAL TOMBS TO TANIS (SAN EL- HAGAR)

The city of Tanis is one of the most important cities in ancient Egypt. It was the northern capital of Egypt and the royal headquarters of the kings of the twenty -first and twenty -two dynasty. It is in the east of the Delta, about 150 km northeast of Cairo, on the ancient Tanis branch of the Nile. The Royal tombs of Tanis was discovered by the French archaeological Pierre Monte in 1999. The material building materials are currently suffering due to many aspects and factors of physical, chemical, biological, and human damage, such as the deterioration and loss of many stone blocks, binding mortar, and decorative units, accumulation of dusts and cracks that are varied in shapes and sizes in the painting, crystallization of salts on the surface and between layers, which led to the separation, fragmentation and peeling of the stone surface and the disappearance of many decorative elements, scenery and colored relives. Therefore, the research aims to study the materials for building tombs to find out the most important physical and chemical changes that occurred to them and led to their deterioration in preparation for the development of a scientific plan for the restoration and conservation of these tombs and their decorative elements. The components of the tombs were studied through investigation and using various analysis methods such as X-Ray Diffraction (XRD), Scanning Electron Microscope with Energy Dispersive X-ray (SEM-EDX) analysis of elements, Polarizing Microscope (PM). physical and mechanical properties of the stones used in the construction of graves were carried out. The results The results indicated that, the tombs were constructed using blocks of restricted limestone and were linked with a mortar of Gypsum, sand and stone powder and used some granite pieces in the doorstep over the entrances, and the main reason for the damage of building materials is a group of natural factors, the most important of which is rain water, the ground water and the various salts it contains due to the low location of the tombs within the archaeological hill and the proximity of the archaeological hill to the salty water sources represented in Lake Manzala, agricultural lands, waterways and agricultural banks.

Colloidal and Thermal Stability of Three-Component Hybrid Materials Containing Clay Mineral, Polysaccharide and Surfactant.

The paper presents the colloidal and thermal stability of the three-component hybrid materials containing halloysite, polysaccharides (alginic acid, cationic cellulose and hydroxyethyl cellulose) and Tritons. TX-100, TX-165 and TX-405 were used as non-ionic surfactants. Stability and other properties of the hybrid materials were tested by the following methods: UV-Vis, TGA (thermogravimetric analysis) and DSC (differential scanning calorimetry), CHN (elemental analysis), SEM-EDX (scanning electron microscopy with energy dispersive X-ray spectroscopy) and tensiometry. According to the results with the increasing polymer concentration the colloidal stability of the tested systems also increases. Moreover, the addition of the surfactants causes the increase of polysaccharide adsorption but the colloidal stability of the tested systems decreases due to large weights of formed aggregates. As follows from the thermal analysis, the comparison of the TG/DTG-DSC curves obtained for the investigated polymers confirms that their thermal decomposition courses have some common features. The obtained results have the application potential in the formation of the materials for the pollutants removal from water and sewages.

Twin-screw extrusion of vitamin D3/iron-blend granules in corn and lentil composite flours: Stability, microstructure, and interaction of vitamin D3 with human osteoblast cells.

Vitamin D3 (VD3) and iron-blend granules were blended with corn and lentil composite flour (75/25, w/w) and fed into a pilot-scale twin-screw extruder to produce ready-to-eat snacks. The morphology and microstructure of extruded snacks were examined using scanning electron microscopy with energy-dispersive X-ray (SEM-EDX), X-ray powder diffraction, and FT-IR. Differential scanning calorimetry and thermogravimetric analysis measured the melting temperature and thermal stability of the extrudates. SEM and FT-IR analysis demonstrate that micronutrients are mixed well in formulations used in extrudates at high shear and high temperatures. The SEM-EDX exhibited the presence of iron, whereas high performance liquid chromatography measurements confirmed the significant retention of VD3 in the extruded snacks. The interaction between VD3 and human osteoblast cells was studied using live imaging and the MMT assay. Overall, for the first time, VD3 and Fe2+ blend granules have been used in an extrusion platform, which has significant potential for the intervention of VD3 and iron deficiencies. PRACTICAL APPLICATION: For the first time, we reported the use of VD3/iron-blend granules in extruded products. The findings of this work demonstrated the thermal stability and capability of providing adequate quantities of VD3 and iron in corn flour/lentil flour/VD3-iron blend extruded snacks. Furthermore, the interaction of VD3 with osteoblast cells highlights the potential health benefits of the extrudates.

An experimental study on the adsorption behavior of gold glycinate complex on graphene oxide

Graphene oxide (GO) has recently gained plenty of attention as an effective adsorbent for gold recovery from leaching solutions, primarily due to its larger surface area compared to activated carbon (AC). In this study, the adsorption behavior of gold glycinate complex (Augly2−) on GO surface was investigated using equilibrium isotherm and kinetic studies for the first time. The optimal conditions for adsorption were determined using an experimental design software (DX-13) based on the response surface method (RSM). These conditions were found to be a pH of 10.5, GO dosage of 0.6 g L−1, gold concentration of 6 mg L−1, and contact time of 10 h, resulting in the adsorption percentage of 74.2% and adsorption capacity of 7.4 mg g−1. The equilibrium isotherm studies indicated that the adsorption process adhered to the Freundlich isotherm model. Additionally, the results of the kinetic study revealed that the pseudo-second-order model exhibited a stronger correlation with the experimental data compared to other kinetic models. Surface analysis studies using Fourier transform infrared (FTIR) spectrometer, X-ray diffraction (XRD), and scanning electron microscope with energy dispersive X-ray (SEM-EDX) spectroscopy demonstrated that the remarkable recovery of Augly2− was mainly attributed to the presence of oxygen containing functional groups on the GO surface.

Exploring the Potential of Polypropylene Fibers and Bacterial Co-Culture in Repairing and Strengthening Geopolymer-Based Construction Materials

This study explored self-healing in geopolymer mortar cured at ambient temperature using polypropylene fibers and bacterial co-cultures of Bacillus subtilis and Bacillus megaterium. Damage degree, compressive strength, ultrasonic pulse velocity (UPV), strength-regain percentage, and self-healing percentage were evaluated. A full factorial design was used, which resulted in an eight-run complete factorial design with four levels in the first factor (polypropylene content: 0%, 0.25%, 0.5%, and 0.75%) and two levels in the second factor (bacteria concentration: 0 (without) and 1 (with)). The results indicate that increasing the polypropylene fiber content enhanced strength regains up to 199.97% with 0.75% fibers and bacteria. The bacteria alone improved strength-regain percentages by 11.22% through mineral precipitation. The analysis of variance (ANOVA) showed no interaction between fibers and bacteria, but both independently improved the compressive strength. Only bacterial samples exhibited positive self-healing, ranging from 16.77 to 147.18%. The analysis using a scanning electron microscope with energy dispersive X-ray (SEM-EDX) and X-ray fluorescence (XRF) also revealed greater calcite crystal formation in bacterial samples, increasing the strength-regain and self-healing percentages. The results demonstrate that polypropylene fibers and bacteria cultures could substantially enhance the strength, durability, and self-healing percentage of geopolymer mortars. The findings present the potential of a bio-based self-healing approach for sustainable construction and repair materials.

Experimental Design and Breakthrough Curve Modeling of Fixed-Bed Columns Utilizing a Novel 3D Coconut-Based Polyurethane-Activated Carbon Composite Adsorbent for Lead Sequestration

This study presents a novel polyurethane-activated carbon composite (PACC) as an effective and sustainable adsorbent for treating lead-ion-contaminated waters. The PACC was characterized using Scanning Electron Microscopy with Energy Dispersive X-ray (SEM-EDX), Fourier Transform Infrared Spectroscopy (FTIR), Brunauer, Emmett, and Teller (BET) surface area analyzer, X-ray Diffraction (XRD), and Thermogravimetric Analyzer (TGA) to evaluate its physicochemical and thermal properties. Furthermore, the PACC was employed in an experimental column adsorption setup to investigate its adsorption performance and to develop a dynamic method suitable for industrial implementation. Parameters such as bed height (50, 100, 150 mm), flow rate (4, 6, 8 mL min−1), pH (2, 4, 6), and initial metal-ion concentrations (10, 50, 100 mg L−1) were examined. The experimental data exhibited strong agreement with the Thomas and Yoon–Nelson models (R2 ≥ 0.96), indicating efficient adsorption mechanisms. Remarkably, the used adsorbent has the potential for facile regeneration without substantial loss in capacity. The PACC demonstrated excellent adsorption performance for lead ions in aqueous solutions in a fixed-bed column system. Thus, the novel PACC material holds the potential for scalable application in industrial settings to address water pollution challenges, especially in regions with uncontrolled effluent discharge.

Ultra-Small Ceria Nanocrystals at Carbon Surface Synthesized by Ultrasound Sonication: A Study of Highly Active Platinum-Cerium Bifunctional Catalysts for Methanol Oxidation and Oxygen Reduction

ABSTRACT Cerium (IV) oxide (called ceria) has gained a lot of interest from researchers due to its high oxygen storage capacity (1) and high tolerance toward CO-like intermediates of methanol oxidation reaction (MOR) (2,3). In our previous study (4), the ceria crystals were synthesized by the modified solvothermal synthesis with urea (5) and grain size of ceria was around 30 µm, even if the crystallite size was only 11 nm. However, even this huge grain-size CeOx particles contributed insignificantly to the catalytic synergetic effect of ceria at the PtCe catalysts toward MOR.The parameters influencing the deposition of Pt nanoparticles (NPs) on the ceria-carbon support by the ethylene glycol (EG) reduction method were investigated in previous study (4). It was found that the influence of energy supply methods on the reaction system needs to be simplified to control the nucleation and growth of Pt NPs better.Although the role of catalytically active components (Pt and CeOx) in catalyst is important, the structure of carbon support affects the catalytic behaviour of the catalyst significantly. The chromium carbide-derived carbon, noted as C(Cr-CDC), synthesized in our previous study (6) is active materials toward oxygen reduction reaction in 0.1 mol dm─3 KOH due to its high number of the active sites at the surface, large specific surface area, and unique micro-mesoporous structure. Therefore, it is a good support material for this study.The purpose of this study was to synthesize a ceria with small grain size, improve the activity of Pt NPs synthesized by tuning the parameters of EG reduction method, and compare the activity of the novel PtCe/C(Cr-CDC) materials and PtCe/C (commercial Ketjenblack carbon) materials.In detail, the ceria-carbon materials were synthesized firstly by ultrasound sonication method in the mixture of EG and sodium hydroxide solutions, called sonochemical method. Later, the Pt NPs were deposited onto the ceria-carbon materials by EG reduction method using the refluxing system. All the materials were characterized with thermal gravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopy with energy dispersive X-ray (SEM-EDX) methods. All the PtCe/C materials were measured in the 3-electrode system in 0.5 mol dm─3 H2SO4 and in a mixture of 0.5 mol dm─3 H2SO4 + 1 mol dm─3 CH3OH to investigate the electrochemical behaviour and MOR activity, respectively.The results of XRD and SEM-EDX revealed that it was possible to synthesize the ultra-small ceria NPs by the sonochemical method. The crystallite size is smaller than 2 nm. EDX confirmed the presence of cerium in measuring areas, however, the grain size of ceria in ceria-carbon was too small to be revealed with SEM. The TGA confirmed that all cerium was deposited onto carbon with approximately 11 wt. % of the total ceria-carbon weight. Besides, XRD and TGA also confirmed the success of Pt deposition method. The electrochemical activity at PtCe/C materials revealed high electrochemically active surface area value (55-80 mPt 2 gPt −1). ACKNOWLEDGEMENT This work was supported by the EU through the European Regional Development Fund TK141 “Advanced materials and high-technology devices for energy recuperation systems” (2014-2020.4.01.15-0011) and Personal Research Grant PRG676. The SEM-EDX measurements were conducted using the NAMUR+ core facility funded by the Estonian Research Council (TT 13). REFERENCES E. Antolini and J. Perez, Int. J. Hydrog. Energy, 36, 15752–15765 (2011).S. Dai, J. Zhang, Y. Fu, and W. Li, New J. Chem., 42, 18159–18165 (2018).D. Y. Chung, K.-J. Lee, and Y.-E. Sung, J. Phys. Chem. C, 120, 9028–9035 (2016).H. Q. V. Nguyen, J. Nerut, H. Kasuk, M. Härmas, P. Valk, T. Romann, M. Koppel, P. Teppor, J. Aruväli, O. Korjus, O. Volobujeva, and E. Lust, J. Solid State Electrochem. (2022).S. B. Atla, M.-N. Wu, W. Pan, Y. T. Hsiao, A.-C. Sun, M.-J. Tseng, Y.-J. Chen, and C.-Y. Chen, Mater. Charact., 98, 202–208 (2014).H. Q. V. Nguyen, J. Nerut, H. Kasuk, V. Grozovski, T. Thomberg, I. Tallo, R. Palm, M. Koppel, T. Romann, R. Härmas, J. Aruväli, M. Külaviir, and E. Lust, Russ. J. Electrochem., 58, 781–797 (2022).

Physicochemical characterization of free troposphere and marine boundary layer ice-nucleating particles collected by aircraft in the eastern North Atlantic

Abstract. Atmospheric ice nucleation impacts the hydrological cycle and climate by modifying the radiative properties of clouds. To improve our predictive understanding of ice formation, ambient ice-nucleating particles (INPs) need to be collected and characterized. Measurements of INPs at lower latitudes in a remote marine region are scarce. The Aerosol and Cloud Experiments in the Eastern North Atlantic (ACE-ENA) campaign, in the region of the Azores islands, provided the opportunity to collect particles in the marine boundary layer (MBL) and free troposphere (FT) by aircraft during the campaign's summer and winter intensive operation period. The particle population in samples collected was examined by scanning transmission X-ray microscopy with near-edge X-ray absorption fine structure spectroscopy. The identified INPs were analyzed by scanning electron microscopy with energy-dispersive X-ray analysis. We observed differences in the particle population characteristics in terms of particle diversity, mixing state, and organic volume fraction between seasons, mostly due to dry intrusion events during winter, as well as between the sampling locations of the MBL and FT. These differences are also reflected in the temperature and humidity conditions under which water uptake, immersion freezing (IMF), and deposition ice nucleation (DIN) proceed. Identified INPs reflect typical particle types within the particle population on the samples and include sea salt, sea salt with sulfates, and mineral dust, all associated with organic matter, as well as carbonaceous particles. IMF and DIN kinetics are analyzed with respect to heterogeneous ice nucleation rate coefficients, Jhet, and ice nucleation active site density, ns, as a function of the water criterion Δaw. DIN is also analyzed in terms of contact angles following classical nucleation theory. Derived MBL IMF kinetics agree with previous ACE-ENA ground-site INP measurements. FT particle samples show greater ice nucleation propensity compared to MBL particle samples. This study emphasizes that the types of INPs can vary seasonally and with altitude depending on sampling location, thereby showing different ice nucleation propensities, which is crucial information when representing mixed-phase cloud and cirrus cloud microphysics in models.