Nitrate Solution Research Articles

Влияние загрязнения таллием на активность ферментов циклов углерода, азота и фосфора в почвах разной буферности

The influence of thallium (Tl) pollution on the activity of enzymes of carbon, nitrogen and phosphorus cycles in ordinary chernozem, brown forest soil and seropeski was studied. Thallium was introduced into the soil in the form of oxide (Tl2O3) and a solution of thallium nitrate (Tl(NO3)3) in 0.5, 1, 3, 10, 30 conditionally permissible concentrations. Incubation was carried out for 10 days. As a result of the study, it was found that contamination of the studied soils with Tl compounds leads to a decrease in the activity of enzymes involved in the carbon, nitrogen and phosphorus cycles. The change in enzyme activity depends on the chemical form (oxide or nitrate) of Tl and the concentration of the element in the soil. Phosphatase activity has the greatest sensitivity to contamination by thallium compounds. Ordinary chernozem showed the greatest resistance to thallium contamination, and seropeski showed the least.

Green synthesis of size-controlled silver nan particles and their anti-cancer potentiality

Silver nanoparticles (Ag-NPs) are now well recognized as one of the most prevalent kinds of materials that are put to use in a wide variety of biomedical applications, most notably as an anti-cancer agent. In the current investigation, Ag-NPs were effectively produced by reducing silver ions by employing the leaf extract of Artocarpus heterophyllus as a source of reducing and capping agents. By altering the quantity of the silver nitrate solution, we successfully synthesized three distinct kinds of Ag-nanoparticles that were mediated by Artocarpus heterophyllus leaf extract. The X-ray diffraction (XRD) analysis first confirmed the formation of metallic silver, where peaks were found at fixed angles. XRD method was also used to validate the crystal geometry of the Ag-NPs, revealing that the Ag-NPs had a face-cantered cubic structure. The calculated average crystallite sizes of Sample-1 Ag-NPs, Sample-2 Ag-NPs, and Sample-3 Ag-NPs were 20.34 nm, 16.99 nm, and 18.88 nm, respectively. Ag-NPs were also confirmed from EDX analysis and firm Ag peaks, including several organic compound peaks. The nanoparticle’s range was between 120 nm and 220 nm, and the average particle size was near 170 nm, as found in the SEM image, and accumulation was observed in the SEM image. Using Fourier Transform Infrared (FT-IR) spectroscopy, we determined the functional groups of organic compounds that might be responsible for reducing agents and the presence of capping agents on the surface of Ag-NPs. The cell viability test was used to assess the cytotoxicity using the HeLa cell, a human carcinoma cell. The results revealed that the produced Ag-NPs demonstrated toxicity against carcinoma cells.

Silver-Matrix Composite with Fullerene Soot Nanoparticles Produced by Electrodeposition

The presented work demonstrates the capability of obtaining composite powder, silver-fullerene soot, by the electrolytic deposition of silver from an aqueous solution of silver nitrate. The morphology of particles was studied as a function of fullerene soot concentration and current density. The microstructure of compact materials obtained by hot pressing was investigated. The hardness of the compact material increased up to 30% and the same corrosion properties relative to pure silver were obtained using a similar technology.

Dark-Field Microscopy of Au@Ag Core Shell Nanoparticles during Electrochemical Conversion Reactions

Nanoparticles (NPs), which can nowadays be synthesized in various shapes and compositions, provide special physical properties that can strongly differ from their respective macroscopic counterparts. In particular due to the highly increased surface-to-volume ratios, NPs are frequently used as catalyst material.(1) Furthermore, metal NPs exhibit adjustable spectral properties arising from the interaction of the conduction band electrons with electromagnetic radiation, called localized surface plasmon resonance (LSPR).(2) The NPs appear colorful, where spectra of single NPs contain fundamental information about the size, shape and composition of the NP. Using Dark-Field Microscopy (DFM), the LSPR spectra of individual NPs can be precisely detected by hyperspectral imaging and CCD imaging. Combining this method with electrochemistry allows the monitoring of electrochemical processes on a single NP level.(3) In our work we focus on Au@Ag Core Shell NPs which are a promising candidate for catalytic applications. The LSPR spectra of the core shell NPs were herein tracked during the electrochemically induced dissolution of the Ag shell in nitrate solution exhibiting a “naked” Au core with possibly increased catalytic activities. With this spectro-electrochemical approach, an intensity decrease accompanied by a spectral red-shift was found during the dissolution of the Ag, which correlated with the simultaneously obtained current responses.Figure 1: Left: DFM CCD images of core shell NPs before and after linear sweep voltammetry (LSV) are displayed (-0.2 to 0.6 V vs Pt, 5 mV/s), center: LSPR intensity gradient of > 600 core shell NPs which were individually tracked during the LSV (black) including the current response (red), right: LSPR spectra of a representative core shell NP before and after the LSV.References(1) Ealia S. A. M.; Saravanakumar M. P. IOP Conf. Ser.: Mater. Sci. Eng. 2017, 263, 032019.(2) Sambur J. B.; Chen P. Annu Rev Phys Chem 65, 395–422.(3) K. Wonner et al. J. Am. Chem. Soc. 2018, 140, 12658–12661. Figure 1

Eggshell-Mediated Hematite Nanoparticles: Synthesis and Their Biomedical, Mineralization, and Biodegradation Applications

The present study demonstrates the synthesis of phase pure hematite (α-Fe2O3) nanoparticles (NPs) using collagen protein and calcium carbonate extracted from eggshell membranes and eggshells, respectively, as organic additives. To test the influence of organic additives on the quality of the resulting NPs, the amount of eggshell powder was varied between 1 to 5 g in aqueous iron nitrate solution. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and RAMAN analysis confirmed the formation of hematite NPs without any impurities. FTIR spectra revealed the presence of polyphenolic constituents on the surface of the resulting NPs as stabilizers, which may potentially be responsible for the observed antioxidant and antibacterial properties. Furthermore, the stable phase and the presence of low defects divulged the high hardness value (~983 HV) and fracture toughness (8.59 MPa m1/2), which can be exploited for bone implantation. The FE-SEM results demonstrate the formation of spherical particles, which are well-separated NPs. The results of a biodegradation study which was carried out in phosphate-buffered saline (PBS) revealed that the as-prepared NPs retained their hardness even after 72 h of soaking. These prepared NPs showed 95% radical scavenging activity (RSA) and were good carriers against S. aureus bacteria. Moreover, the SEM images of the mineralization of iron oxide NPs confirmed the formation of new bone. After 5 weeks, all pores were filled, and the minerals were deposited on the surfaces of the scaffolds.

Liquid plasma spraying of NiO-YSZ anode layers applicable for SOFC

Plasma spraying (PS) from liquid feedstocks is a promising alternative for fabricating the NiO-YSZ anodes for Solid Oxide Fuel Cell (SOFC). However, despite the inherent advantages of the PS process, the plasma sprayed anodes are still inferior to the conventional ones prepared by wet-ceramic techniques due to the difficulty of achieving the optimal porosity level. This study shows that due to recent development, the NiO-YSZ anode layers with desirable porosity and microstructure can now be effectively fabricated in a one-step process using PS equipment with a water-argon stabilized plasma torch. As a liquid feedstock, we utilized Ni nitrate (hexahydrate) solutions and YSZ suspensions with different ratios, using ethanol or water as solvents. We show that the ethanol-based feedstock provides a favorable microstructure and porosity of the resulted layers over the water-based one. In addition, apart from NiO and YSZ phases, the layers deposited with ethanol solvent contained even metallic Ni. Different ratios of Ni nitrate to YSZ in ethanol-based feedstocks greatly affected the layer’s characteristics; when the content of Ni nitrate was high, the resulting layers had a non-uniform morphology with a very porous microstructure. On the contrary, the equal contents of Ni nitrate and YSZ in the feedstock resulted in the most optimal layer's microstructure, chemical composition, and thus sufficient electrical resistance, making such material potentially useful as anode for SOFC.

IMPROVED SORPTION OF PRASEODYMIUM IONS FROM NITRATE SOLUTIONS BY ACTIVATED ION EXCHANGERS

In this research, we investigated the praseodymium ions sorption by the ion exchangers KU-2-8 (H+form) and AV-17-8 (OH-form) as an interpolymer system called "KU-2-8:AV-17-8" (X:Y) with the molar ratio of ionic groups X:Y (6:0, 5:1, 4:2, 3:3, 2:4, 1:5, and 0:6) in praseodymium nitrate solution. To be clear, two cross-linked polymers having active functional groups that are in the same solution but not in direct contact form an interpolymer system. The purposeof our research to demonstrate how activating ion exchangers as functional polymers by remote contact in an aqueous medium enhances the sorption of a variety of valuable metals and their compounds from industrial waste solutions, including praseodymium. Objects.Ion exchangers that are mutually activated in an aqueous medium undergo conformational and electrochemical changes that lead to a shift in their state from neutral to highly ionized and an increase in their sorption activity toward target metal ions. Results.The experimental findings showed that the sorption activity of the interpolymer system KU-2-8:AV-17-8 (5:1) increased significantly when compared to praseodymium ions (43 %), but the sorption activity of the raw KU-2-8 (6:0) and raw AV-17-8 (0:6) had the same values of 25 % and 5 %, respectively. Conclusion. This research sheds light on a novel and promising approach to improve the efficiency of ion exchangers, opening possibilities for the effective recovery and removal of valuable metals from complex solutions. Additionally, it holds practical implications for sustainable waste management and resource recycling, contributing to the advancement of environmental protection and resource conservation in various industrial sectors. Further investigations and optimization of the interpolymer system could yield substantial benefits for greener and more resource-efficient future sorption technologies.

Analysis of sorption/desorption of cadmium and lead in the legal amazon soils

Sorption and desorption tests were carried out for competitive and non-competitive systems with isotherms to verify the presence of Cd and Pb in soils. The soils investigated were: (i) with natural content of organic matter and (ii) with residual content of organic matter. Hydrated nitrate salts of Cd and Pb diluted in 0.01 M calcium nitrate solution in six concentrations were used for the Cd solutions and, for the solutions of Pb, five concentrations. For multielement solutions, mixtures of the simple Cd and Pb solutions in a 1:1 ratio were used. The results of the first stage tests (i) showed good adjustments of the experimental data to the isotherms of Langmuir, Freundlich and Linear, which did not occur for the tests in stage (ii). According to the tests (i), the organic matter was the soil attribute of dominant influence in the sorting mechanisms. The parameters Qo and Kd were adequate to evaluate the adsorption of the studied metals, especially Cd. In step (ii), there was a significant increase in metal retention, especially for element Pb in the samples of Haplic Cambisol (AM) and Red-Yellow Latosol1 (RO), justified by the combined action of (1) increasing the surface area of the mineral fraction, previously covered by organic matter; and (2) increase in soil pH. The Cd element was more bioavailable in relation to the Pb. This was confirmed by the high desorption values observed for Cd. The samples of Haplic Cambisol and Red-Yellow Latosol demonstrated greater capacity to retain Cd and Pb.

The effect of pressing parameters and hardener content on the properties of plywood bonded with propylamine-UF adhesive

ABSTRACT Research on reducing the formaldehyde emission from wood-based materials bonded with urea-formaldehyde (UF) resin has attracted the attention of scientists for years. Many studies investigated the possibility of using amines for this purpose; however, the outcomes of the vast majority of them have shown that the limiting factor is reduced resin reactivity and consequently, deterioration of the strength of the resultant materials as well. Therefore, the aim of this research work was to investigate and evaluate the effect of the pressing protocol applied (pressing temperature and time), and hardener content (20% ammonium nitrate solution) on the properties of plywood bonded with UF adhesive system modified with 1% of propylamine. Manufactured plywood was tested in terms of shear strength (in dry and wet conditions) and formaldehyde emission (measured initially and after 4 weeks). Based on the results, it was found that it is possible to produce plywood with equally good characteristics as the reference, non-modified variant by increasing hardener content from 3% to 7%, increasing pressing temperature from 120°C to 150°C, and extending the pressing time from 240 to 300 s. Markedly, the implementation of these adjustments also contributed to a further decrease in formaldehyde emission.

Preparation and Properties of Temperature-Sensitive Silver-Loaded Antibacterial Sericin/poly (N-isopropylacrylamide) Hydrogel

In this paper the silver ions in a silver nitrate solution were reduced to the Ag element by silk sericin (SS); then, N-isopropylacrylamide (NIPAAm) was added into the mixed solution of SS and silver nitrate to form the bifunctional SS/NIPAAm-Ag3 hydrogel with interpenetrating network structure with N,N-methylenebisacrylamide (BIS) as a cross-linking agent, ammonium persulfate (APS) as a initiator and N, N, N’, N-tetramethylethylenediamine (TEMED) as a co-initiator. SEM showed that the SS/NIPAAm-Ag3 hydrogel had a regular honeycomb structure and high porosity. It was confirmed by DSC that the SS/NIPAAm-Ag3 hydrogel exhibited temperature sensitivity, and its Lower Critical Solution Temperature (LCST) was about 35 °C. The swelling degree of the SS/NIPAAm-Ag3 hydrogel was obviously higher than that of SS/NIPAAm hydrogel at 25 °C and 37 °C. The time required for deswelling equilibrium was shortened by 2 h compared with SS/NIPAAm hydrogel, showing that the introduction of a certain amount of nano-Ag could give hydrogel excellent swelling and deswelling properties. The bacteriostatic rates against Esherichia coli (E.coli) and Staphylococcus aureus (S. aureus) reached 99.8% and 93.38%, respectively. A cytotoxicity test proved that SS/NIPAAm-Ag3 hydrogel had no adverse effects on the human cell health. The development of this temperature-sensitive and antibacterial hydrogel provides a new possibility for the preparation of hydrogel medical dressing.

Foliar Fertilization with Molybdate and Nitrate Up-Regulated Activity of Nitrate Reductase in Lemon Balm Leaves

The foliar feeding of soil-grown plants with essential elements such as molybdate can restore their Nitrate reductase activity. However, the activity of nitrate reductase under the foliar feeding of plants with molybdate and nitrate in hydroponic conditions has not been investigated. Thus, we wanted to investigate the effect of the foliar feeding of molybdate and nitrate on the nitrate reductase activity in the leaves of lemon balm plants under hydroponic conditions. Nitrate and molybdate solutions were applied by spraying the leaves of lemon balm plants and the nitrate reductase activity was determined by the colorimetric method. The results of our study demonstrated that the application of molybdate and KNO3 solution enhanced the nitrate reductase activity in the leaves of lemon balm plants. Importantly, our results indicate that foliar fertilization with nitrate and molybdate can improve nitrogen metabolism and carbon fixation in the leaves of lemon balm plants under hydroponic conditions.

Antibacterial Activity of Green Synthesized Eugenia jambolana Seeds Extract Mediated Silver Nanoparticles

The present study uses silver nanoparticles that are biosynthesized from Eugenia jambolana aqueous silver nitrate solution jambolana fresh seed extracts were combined with silver nitrate (AgNO3) to form the silver nanoparticle. UV-Vis Spectrophotometry, XRD, SEM, and FTIR were used to characterise the synthesised silver nanoparticles. It was established that nanoparticles had formed in the sample by SEM examination, which revealed that they had a spherical shape. Nanoparticles from seed extracts showed more antibacterial activity on Pseudomonas aeruginosa followed by Bacillus subtilis, Vibrio cholerae, and Staphylococcus aureus. This study makes evidence that seed extracts of Eugenia jambolana act as an excellent capping agent for the formation of silver nanoparticles and show immense Pharmacological activities. Hence, these AgNPs can be used as an antimicrobial agent in treating many medical complications. In this present study, the antibacterial activity of green synthesized silver nanoparticles from Eugenia jambolana seeds shows the zone of inhibition against all four pathogens.

Further extension of the Madrid-2019 force field: Parametrization of nitrate (NO3−) and ammonium (NH4+) ions

The importance of nitrate and ammonium salts both in the environment and in biological processes cannot be questioned. In this work, using the TIP4P/2005 water model, aqueous solutions of nitrate and ammonium electrolytes are parametrized using scaled charges while keeping a rigid structure and nonpolarizable charge distributions. The models are optimized by systematically testing a set of properties for twelve electrolytes—eight nitrate and four ammonium salts—thus, enlarging the number of potential chemical species encompassed within the Madrid-2019 force field for ions. The capacity of the force field for predicting densities, ion–ion and ion–solvent structures, and transport properties of the solutions comprised by the trial batch of salts was tested and discussed. Both the dependence of the densities with the salt concentration and the solution structure were nicely reproduced by the models in the whole concentration range without any trace of precipitating events and with improved accuracy in comparison with recently reported models, while the agreement of the simulated transport properties with experimental data ranges from good to reasonable, depending on the ion/counterion pair. These scaled charge models might be considered as force fields embodying a reasonable compromise between exactness and general applicability and also as an important step in the development of accurate models for polyatomic ions.

Carica papaya Crude Extracts Are an Efficient Source of Environmentally Friendly Biogenic Synthesizers of Silver Nanoparticles

Metallic nanoparticles are very useful, effective, and usually synthesized by toxic and expensive chemicals. Silver nanoparticles (AgNPs), measuring less than 100 nm, have shown promising impact in several biomedical investigations. These can inhibit microbial growth and aid in medicine administration. Six substrates of Carica papaya were used to synthesize silver nanoparticles that can limit the growth of bacteria and fungi. In this article, we report the synthesis of AgNPs from the leaf, seed, callus, peel, fruit juice, and bark of Carica papaya. AgNPs synthesized from callus showed the most promising results when tested against the growth of bacteria like Xanthomonas campestris, Erwinia carotovera, Bacillus subtilis, and fungi (Aspergillus niger and Fusarium oxysporum) when compared with other extracts’ efficacy, and the callus was regenerated from petiole and midrib explants of Carica papaya in MS basal media supplemented with NAA and Kinetin (1 + 0.5 mg/L). A ratio of 1:20 of substrate extract to 1 mM AgNO3 produced the most effective nanoparticles in terms of capping, quality, and stability when tested through surface plasmon resonance (SPR) within the 400–435 nm range. The nanoparticle sizes of all six types were measured using Image J software on micrographs of SEM at 200 nm resolution. The average diameters were analyzed through Origin software, and the finest AgNPs were observed to be synthesized from callus extract, i.e., 18.91 nm with rod-like morphology. Energy dispersive X-ray (EDX) at 2.6 keV revealed 43.38, 75.39, 70.611, 36.54, 58.57, and 45.94 percent elemental silver in AgNPs formed from the leaf, callus, juice, seed, bark, and peel extract, respectively. Silver nanoparticles synthesized from callus extract were smaller and exhibited the most effective antimicrobial potential, with the highest inhibitory zone of 19 mm against Xanthomonas campestris bacterium and up to 14 mm against Aspergillus niger fungus. Furthermore, the percentage of elemental Ag (measured through EDX) was found to be highest in the nanoparticles synthesized from callus compared to those synthesized from the leaf, seed, peel, fruit juice, and bark of Carica papaya. Hence, the callus extract is the most suitable substrate for the reduction of silver nitrate solution in 1:20 to form the finest silver nanoparticles in an effective biogenic way.

An efficient wastewater treatment through reduction of organic dyes using Ag nanoparticles supported on cellulose gum beads

This work reports silver nanoparticles (AgNPs) supported on biopolymer carboxymethyl cellulose beads (Ag-CMC) serves as an efficient catalyst in the reduction process of p-nitrophenol (p-NP) and methyl orange (MO). For Ag-CMC synthesis, first CMC beads were prepared by crosslinking the CMC solution in aluminium nitrate solution and then the CMC beads were introduced into AgNO3 solution to adsorb Ag ions. Field emission scanning electron microscopy (FE-SEM) analysis suggests the uniform distribution of Ag nanoparticles on the CMC beads. The X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analysis revealed the metallic and fcc planes of AgNPs, respectively, in the Ag-CMC catalyst. The Ag-CMC catalyst exhibits remarkable reduction activity for the p-NP and MO dyes with the highest rate constant (kapp) of a chemical reaction is 0.519 and 0.697 min−1, respectively. Comparative reduction studies of Ag-CMC with CMC, Fe-CMC and Co-CMC disclosed that Ag-CMC containing AgNPs is an important factore in reducing the organic pollutants like p-NP and MO dyes. During the recyclability tests, the Ag-CMC also maintained high reduction activity, which suggests that CMC protects the AgNPs from leaching during dye reduction reactions.

Glass-Containing Matrices Based on Borosilicate Glasses for the Immobilization of Radioactive Wastes

Glass-containing materials are widely considered among the most reliable materials for the immobilization of radioactive waste materials. The present work considers the synthesis of glass–ceramic and glass crystalline composite materials based on borosilicate glasses. The synthesis of glass–ceramic materials was carried out by a gradual temperature decrease, followed by crystallization for several hours. Sintering of crushed samples with crystalline components was carried out as an alternative procedure. Porous glasses were produced from glass melts by quenching. After impregnating the resulting porous materials with aqueous solutions of cesium nitrate, compaction of the glass was carried out to form glass crystalline composites. The thermochemical characteristics of the parent glasses were determined using the differential scanning calorimetry method. The phase composition and structure of the glass-containing materials were determined using X-ray phase analysis, X-ray spectral microanalysis, and Raman spectroscopy.

Morphogenesis of immune formations of ducks' intestine

The morphogenesis of immune formations of duck intestines was studied. Material for histological studies was taken from Blagovarsky cross broiler ducks aged from one to 420 days. The obtained sections were stained with Karatsi's hematoxylin and eosin – to establish the features of the microscopic structure of intestinal immune formations, Weigert's hematoxylin and picrofuchsin according to Van Gieson and aniline blue in combination with acid fuchsin and Orange G according to Mallory – to identify collagen fibers, resorcin-fuchsin according to Weigert – for differentiation of elastic fibers. To determine reticular fibers, sections were impregnated with 1–2 % argentum nitrate solution according to the modified Kelemen method. Electron microscopy studies were carried out to study the ultrastructure of the immune formations of the intestines of 180-day-old ducks. The studies have established that the intestinal wall in the places where immune formations of the intestines in ducks are localized is formed by tunica mucosa, tunica muscularis and tunica serosa, the area of which in all immune formations changes unevenly and asynchronously with the birds’ age. The tunica mucosa occupies the largest area, which changes unevenly and asynchronously, reaching maximum values (from 71.66 ± 0.25 to 81.28 ± 0.19 %) during the first 25 days of the ducks' life. The tunica muscularis occupies a smaller area than the tunica mucosa. It decreases unevenly in the first 25 days of a bird’s life, and in older birds it increases and reaches maximum values (35.68 ± 0.49–46.67 ± 1.39 %) in 330- and 420-day-old birds. The tunica serosa occupies the smallest area. In day-old birds, this indicator is the highest (from 2.47 ± 0.07 to 6.20 ± 0.02 %) and decreases with age by 1.24–6.52 times. Lymphoid tissue, which determines the functions of immune formations, is located in their tunica mucosa and tunica muscularis. It is detected in the tunica mucosa of all immune formations and the tunica muscularis of caecal diverticula from the bird’s one-day age, in the tunica muscularis of other immune structures – from the age of 10–20 days. The total area of lymphoid tissue increases from one day (27.03 ± 0.88–31.72 ± 0.04 %) to 150 days of age in ducks in Peyer's patches of the duodenum and jejunum and cecal diverticula (59.86 %, 59.58 ± 1.28, 65.12 ± 0.50 %), up to 210 days of age in Peyer’s patches of the ileum (71.64 ± 1.03 %), up to 330 days of age in Peyer’s patches of the cecum (37.84 ± 5.12 %), up to 420 days of age in Meckel’s diverticulum (55.24 ± 0.37 %). In older birds, the area of lymphoid tissue decreases, which indicates the beginning of its involution and, accordingly, the involution of immune formations.

Epoxide-Mediated Synthesis of Two-Component Al2O3–TiO2 Aerogels and Their UV-Protective Characteristics

A new method was proposed to synthesize aerogels based on Al2O3–TiO2 by the hydrolysis of mixed solutions of titanium tetrachloride and aluminum nitrate in the presence of propylene oxide, followed by supercritical drying of the obtained gels. The aerogels are characterized by a high specific surface area (140–500 m2/g) and a high specific porosity (1.7–2.7 cm3/g). Heat treatment of the Al2O3–TiO2 aerogels at temperatures up to 600°C does not lead to crystallization of titanium dioxide, whereas the formation of crystalline anatase in aerogels based on individual TiO2 is observed already at a temperature of 450°C. Using the standardized ISO 24443-2016 method, the SPF value of the obtained materials was determined, which turned out to be comparable to the characteristics of a commercial inorganic UV filter based on TiO2 (Kronos 1171). At the same time, the photocatalytic activity of the Al2O3–TiO2 aerogels turned out to be more than 120 times lower than the similar characteristics of the commercial UV filter based on titanium dioxide. The results obtained demonstrated that the Al2O3–TiO2 aerogels are promising as components of sunscreens.

Laser Ablation of a Titanium Target in an Aqueous Solution of Silver Nitrate

Laser Ablation of a Titanium Target in an Aqueous Solution of Silver Nitrate

Controllable synthesis of core-shell SiO2@CeO2 abrasives for chemical mechanical polishing on SiO2 film

The controllable and facile synthesis of SiO2@CeO2 core-shell (CS) composite nanoparticles is crucial for various applications, i.e., chemical mechanical polishing (CMP), nanoreactors, and photocatalysis. However, it is still a challenge to control the synthesis of homogeneous CeO2-coated SiO2 core-shell nanoparticles without additional chemicals or organic solvents. The study investigated the influence of reaction atmosphere, initial pH of the silica colloidal, and the quantity of cerium nitrate on the ceria coating process systematically. Furthermore, the synthesis mechanism of CS composite nanoparticles was ascertained by monitoring changes in pH, zeta potential, secondary size, and morphology over time. The controllable growth of 3%− 67.5% ceria on the surface of silica is realized by controlling the method and timing of adding cerium nitrate and ammonia solution. X-ray photoelectron spectroscopy revealed the Ce-O-Si chemical bonding that combined with the CeO2 at the interfaces of SiO2 core at temperature of 80 °C without post-heating. The material removal rate (MRR) of SiO2 film increased from 32.27 to 294.02 Å/min equipped with CS-7.65% composite nanoparticles as abrasives demonstrated significant improvement. These findings provide valuable insights for the development of SiO2@CeO2 composite nanoparticles in subsequent research.