Photoelectron Spectroscopy Methods Research Articles

Unraveling the anti-corrosion mechanisms of a novel hydrazone derivative on steel in contaminated concrete pore solutions: An integrated study

IntroductionCorrosion-induced deterioration of infrastructure is a growing global concern. The development and application of corrosion inhibitors are one of the most effective approaches to protect steel rebar from corrosion. Hence, this study focuses on a novel hydrazone derivative, (E)-N′-(4-(dimethylamino)benzylidene)-2-(5-methoxy-2-methyl-1H-indol-3-yl)aceto-hydrazide (HIND), and its potential application to mitigate corrosion in steel rebar exposed to chloride-contaminated concrete pore solutions (ClSCPS). ObjectivesThe research aims to evaluate the anti-corrosion capabilities of HIND on steel rebar within a simulated corrosive environment, focusing on the mechanisms of its inhibitory effect. MethodsThe corrosion of steel rebar exposed to the ClSCPS was studied through weight loss and electrochemical methods. The surface morphology of steel rebar surface was characterized by FE-SEM-EDS, AFM; oxidation states of the steel rebar and crystal structures were examined using X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) methods. Further, experimental findings were complemented by theoretical studies using self-consistent-charge density-functional tight-binding (SCC-DFTB) simulations. The performance of HIND was monitored at an optimal concentration over a period of 30 days. ResultsThe results indicated a significant reduction in steel rebar corrosion upon introducing HIND. The inhibitor molecules adhered to the steel surface, preventing further deterioration and achieving an inhibition efficiency of 88.4% at 0.5 mmol/L concentration. The surface morphology analysis confirmed the positive effect of HIND on the rebar surface, showing a decrease in the surface roughness of the steel rebar from 183.5 in uninhibited to 50 nm in inhibited solutions. Furthermore, SCC-DFTB simulations revealed the presence of coordination between iron atoms and HIND active sites. ConclusionThe findings demonstrate the potential of HIND as an effective anti-corrosion agent in chloride-contaminated environments. Its primary adsorption mechanism involves charge transfer from the inhibitor molecules to iron atoms. Therefore, applying HIND could be an effective strategy to address corrosion-related challenges in reinforced infrastructure.

A innovative application of lactose cross-linked adhesive in plywood using hyperbranched network structure with high performance

The use of biomass as raw material to prepare green biomass-based resins for wood adhesives is an effective way to alleviate the oil resource crisis and environmental problems. However, the reported biomass-based adhesives suffer from poor mechanical properties and water resistance, limiting their application to some extent. It is therefore of great interest to investigate new synthetic methods for the preparation of biomass-based adhesives with good mechanical properties and water resistance. In this paper, in order to improve the mechanical properties of biomass-based adhesives, this can be achieved through chemical modification of biomass and hyperbranched network cross-linking strategies. A new biomass-based hyperbranched adhesive, L-PEI, was prepared by co-crosslinking lactose and PEI through air oxidation strategy. The molecular structure of L-PEI was determined using FTIR, 13C NMR, X-ray photoelectron spectroscopy, LC-MS, GPC and other characterisation methods. During the modification process, the addition of PEI leads to the formation of a super branched network structure between lactose and PEI, increasing the crosslinking density and serving as a water barrier. The results of the study show that L-PEI has good adhesive properties and water resistance. Wet shear strength is 1.13 MPa after 3 h in hot water at 63 °C and after soaking in boiling water for 3 h, it is 1.1 MPa. In summary, L-PEI is a green, easy to synthesize and high performance wood adhesive.

The role of defects in thermoluminescence of pure and rare-earth-doped magnesium tetraborate phosphor

The aim of this work was to elucidate the role of defects in energy storage and transfer in X-ray irradiated MgB4O7. Pure and terbium- and erbium-doped magnesium tetraborate was synthesized by the solid state reaction method. The band gap value Eg = 9 eV was estimated using the method of X-ray photoelectron spectroscopy (XPS). Absorption attributed to defects with energy levels located in the forbidden band was found from UV–vis spectroscopy. An interpretation of the thermoluminescence and radioluminescence spectra of pure and doped magnesium tetraborate was proposed. Two different mechanisms for enhancing the thermoluminescent response of MgB4O7 upon doping with rare earth elements were demonstrated.

Passivation behavior of Cr-modified rebar in simulated concrete pore solutions with different pH

In this study, the enhanced passivation effect of Cr-modified rebar compared with carbon rebar has been explored with regard to the formation process of the passive film, which could provide a theoretical basis for the development and application of concrete materials in harsh environments. X-ray photoelectron spectroscopy and capacitance-potential method were used to investigate the composition, structural depth distribution, and semiconductive properties of passive films formed by Cr-modified rebar and carbon rebar in simulated concrete pore solutions with different pH. The kinetics of passive film growth and formation were analyzed by tracking tests of potentiostatic current transients and open circuit potential under natural aeration. The results show that the activation energy of Cr-modified rebar is lower at 14.59 kJ/mol, compared to carbon rebar's 25.36 kJ/mol. In the early stage, Cr-modified rebar can achieve a thinner, more stable initial film in a shorter time than carbon rebar. The rate of reduction of the initial thickening rate of the passive film on Cr-modified rebar is five times than that of carbon rebar per unit pH. The film growth rate after early stage of Cr-modified rebar decreases, whereas that of carbon steel increases, with decreasing pH. The passive film containing Cr oxide or hydroxide enhances the barrier effect of the oxide film to ion migration, and the re-dissociation of Fe oxide hinders the passivation process. This grants the thickness of the stable passive film of the two rebars changing oppositely and the Cr-modified rebar compared to carbon rebar enhance passivation with pH falling.

Thermal Instability of Gold Thin Films

The disintegration of a continuous metallic thin film leads to the formation of isolated islands, which can be used for the preparation of plasmonic structures. The transformation mechanism is driven by a thermally accelerated diffusion that leads to the minimalization of surface free energy in the system. In this paper, we report the results of our study on the disintegration of gold thin film and the formation of nanoislands on silicon substrates, both pure and with native silicon dioxide film. To study the processes leading to the formation of gold nanostructures and to investigate the effect of the oxide layer on silicon diffusion, metallic film with a thickness of 3 nm was deposited by molecular beam epitaxy (MBE) technique on both pure and oxidized silicon substrates. Transformation of the thin film was observed by low-energy electron microscopy (LEEM) and a scanning electron microscope (SEM), while the nanostructures formed were observed by atomic force microscope (AFM) method. Structural investigations were performed by low-energy electron diffraction (LEED) and X-ray photoelectron spectroscopy (XPS) methods. Our experiments confirmed a strong correlation between the formation of nanoislands and the presence of native oxide on silicon substrates.

Composition and thermoelectric properties of structures based on iron silicide grown by pulse laser deposition

Silicon compounds have a wide range of electrical properties. In particular, the possibility of creating thermoelectric converters based on them looks extremely attractive. The use of most silicides as thermoelectrics today is limited by their low efficiency. The development of approaches consisting in the creation of low-dimensional structures using non-equilibrium formation methods is one of the priority directions for improving the properties of thermoelectric generators. Determination of the effect of technological regimes on the structure, phase-chemical composition and thermoelectric properties of metal-silicide structures is a key task, the solution of which will allow creating highly efficient thermoelectric generators based on them. Thin-film structures with a layer thickness of ~50 nm formed at different growth temperatures by pulsed laser deposition on two types of substrates: sapphire and gallium arsenide coated with an Al2O3 nanolayer were studied in this work. On the formed samples, a chemical analysis and a study of the phase composition were performed. Chemical analysis was carried out by X-ray photoelectron spectroscopy with the chemical composition depth profiling. The phase composition was studied by Raman spectroscopy. In addition, analysis of the elements in the films was carried out by X-ray spectral microanalysis based on a scanning electron microscope. To determine the thermoelectric properties of the formed thin-film structures, the temperature dependences of the Seebeck coefficient and the electrical conductivity coefficient were recorded. The dependence of the thermoelectric characteristics of iron silicide films on the phase composition is analyzed. In particular, measurements of the thermoelectric properties of FeSix thin-film structures registered the manifestation of a strong thermoelectric effect in layers with the maximum number of chemical bonds between iron and silicon. The parameters of the growth process at which the most effective formation of iron-silicon chemical bonds is achieved were determined using the method of X-ray photoelectron spectroscopy. Line shifts from the beta phase of iron disilicide were found in the Raman spectra and the reasons for their appearance were proposed

Nano-emulsification method as a strategy for oil soluble corrosion inhibitor transform to water soluble

Corrosion inhibitor is one of the most economical and effective approaches to protecting metal pipes in the oil and gas industries. However, a great amount of corrosion inhibitors such as imidazoline, are difficult to distribute fast due to their poor solubility or dispersibility in water, which results in inhomogeneous concentration distribution and ineffectiveness. In this study, nano-emulsification technique was developed to improve the dispersity of mercaptoacetic acid-modified oleic imidazoline (MOI) in corrosive water. The formulation of nanoemulsion is optimized with the phase inversion temperature (PIT) and droplet diameter. The prepared nanoemulsion which the hydrophilic lipophilic balance value (HLB) was 11.5 and the loading of corrosion inhibitor was 20 wt% exhibited remarkable water dispersion performance and its mean particle size was less than 100 nm. Moreover, its dispersion performance in water was significantly better than that of the paraffin oil system, and was similar in the ethanol system. The inhibition performances and mechanisms of nanoemulsion for L245 carbon steel in the H2S/CO2 containing 5.0 wt% NaCl solution were investigated with weight loss measurements and electrochemical tests. In terms of inhibition efficiency, the corrosion inhibitor encapsulated in nanoemulsion was exceeding 90%, which was comparable to the system employing ethanol and liquid paraffin as solvents. Further experimental results indicated that the nanoemulsion system was more consistent with the Freundlich adsorption model, unlike the other two systems which followed the Langmuir adsorption model. The morphology and composition of corrosion products were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) methods. The SEM and XPS results demonstrated that the nanoemulsion system did not change the material type of corrosion products, but had a visible influence on their morphology. In addition, the inhibition mechanism was also revealed by theoretical calculations. These findings suggest that nano-emulsification technique has the potential to improve the solubility or dispersibility of oil soluble corrosion inhibitor, thereby expanding its application fields.

Revealing charge migration in a Multi-Multi photocatalyst by in situ irradiated X-ray photoelectron spectroscopy

Constructing efficient photocatalysts to produce solar fuels has been regarded as a potential way to alleviate energy crisis and environmental pollution. So far, simply modified single- and dual- component photocatalysts still suffer low efficiency due to their inherent weaknesses, making researchers turn their attention to multiple modified multi-component photocatalysts (“multi-multi” photocatalysts). However, the complex structure and composition of “multi-multi” photocatalysts will make it difficult for in-depth investigations on their working mechanisms, principally due to the lack of a method for direct observation of the migration route of charge carriers under the light irradiation in these systems. Herein, we report an in situ irradiated X-ray photoelectron spectroscopy (ISI-XPS) method to show the transfer pathway of charge carriers through the shifts of binding energies using a triple-modified WS2/carbon nanofibers (CNFs)/ZnIn2S4 model system. With this method, we manage to reveal the role of each subcomponent and demonstrated that the synergy of multiple modifications significantly enhances the performance of the “multi-multi” photocatalyst. This novel method opens up a new avenue for studying the mechanisms of photocatalytic systems, facilitating the future development of highly efficient photocatalysts.

In Situ Gravimetric Probing of Copper Sulfide Formation on the Counter Electrode for Quantum Dot Sensitized Solar Cells

Copper sulfide is a classical counter electrode (CE) catalytic material for the high catalytic activity of polysulfide in quantum dot-sensitized solar cells (QDSSCs). Actually, copper sulfide is a complicated compound. Different preparation methods will lead to the difference in the morphology and structure of copper sulfide, which has a profound impact on its catalytic activity. However, the formation mechanism and electrochemical properties of copper sulfide are rarely reported in the field of QDSSCs. Herein, we report an approach to obtain a high-stability counter electrode material by the electrochemical synthesis in sodium sulfide solution. The in situ electrochemical quartz crystal microbalance (EQCM) method was also employed to reveal the detailed transformation mechanism of copper vulcanized into copper sulfide during cyclic voltammetry in sodium sulfide solution. According to the calculation results of mpe theory, the formation of copper sulfide is accompanied by side reactions such as the conversion of polysulfide ions and water oxidation. Copper sulfide was proven to be a copper-rich phase by X-ray photoelectron spectroscopy (XPS) and other characterization methods. The photoconversion and stability of QDSSCs were studied using CdSe QD as the sensitizing material. The results show that the performance of copper sulfide prepared by this working method is better than the CE prepared by chemical bath deposition (CBD), and the replicability of photoelectric conversion efficiency (PCE) is better than CBD-CE. This work has theoretical significance to reveal the complex formation mechanism, electrochemical process mechanism, and working mechanism of copper sulfide in QDSSCs.

Double Thionated Pyrimidine Nucleobases: Molecular Tools with Tunable Photoproperties.

Sulfur-substituted nucleobases are DNA and RNA base derivatives that exhibit extremely efficient photoinduced intersystem crossing (ISC) dynamics into the lowest-energy triplet state. The long-lived and reactive triplet states of sulfur-substituted nucleobases are crucial due to their wide range of potential applications in medicine, structural biology, and the development of organic light-emitting diodes (OLEDs) and other emerging technologies. However, a comprehensive understanding of non-negligible wavelength-dependent changes in the internal conversion (IC) and ISC events is still lacking. Here, we study the underlying mechanism using joint experimental gas-phase time-resolved photoelectron spectroscopy (TRPES) and theoretical quantum chemistry methods. We combine 2,4-dithiouracil (2,4-DTU) TRPES experimental data with computational analysis of the different photodecay processes, which are induced by increasing excitation energies along the entire linear absorption (LA) ultraviolet (UV) spectrum. Our results show how the double-thionated uracil (U), i.e., 2,4-DTU, appears as a versatile photoactivatable instrument. Multiple decay processes can be initiated with different ISC rates or triplet-state lifetimes that resemble the distinctive behavior of the singly substituted 2- or 4-thiouracil (2-TU or 4-TU). We obtained a clear partition of the LA spectrum based on the dominant photoinduced process. Our work clarifies the reasons behind the wavelength-dependent changes in the IC, ISC, and triplet-state lifetimes in doubly thionated U, becoming a biological system of utmost importance for wavelength-controlled applications. These mechanistic details and photoproperties are transferable to closely related molecular systems such as thionated thymines.

Pure and Sm doped CeO2 Nanoparticles: An insight into the Room Temperature Ferromagnetism and Photocatalytic Dye Degradation

AbstractCeO2 nanoparticles (7–28 nm) and Sm‐doped (5, 10, 15, and 20 %) CeO2 nanoparticles are synthesized using a simple chemical precipitation technique. The defects are studied using Raman spectroscopy, and the presence of defects as oxygen vacancies is verified using the longitudinal optical mode. The optical band gap is determined using UV‐Vis spectroscopy. The reduction in the optical band gap with increasing particle size might be related to quantum confinement, which causes localized states to form due to oxygen vacancies when Ce4+ is reduced to Ce3+. An increase in band gap is observed with increasing Sm concentration, and the optical band gap is smaller than pure CeO2. The electronic structure is investigated using the X‐ray photoelectron spectroscopy (XPS) method, which studied the contributions of each ionic state, namely Ce3+ and Ce4+. Room temperature ferromagnetism (RTFM) is observed for doped as well as undoped samples. The saturation magnetization for 28 nm pure CeO2 NPs is obtained as Ms=5.6*10−4 emu/g, whereas for Sm‐doped samples, we found an increased value of 3.5*10−2 emu/g. The samples are scrutinized for UV‐irradiated photocatalytic dye degradation. The origin of RTFM behaviour and efficient photocatalytic activity are from oxygen vacancies at the lattice sites.

Localization of the E. coli Dps protein molecules in a silicon wires matrix according to scanning electron microscopy and X-ray photoelectron spectroscopy

The work is related to the study of the morphological features of silicon wires arrays combined with a nanomaterial of natural origin, a bacterial ferritin-like protein Dps, and their relationship with the composition of the surface and interior. A silicon wires array was formed by metal-assisted wet chemical etching. To obtain recombinant protein, Escherichia coli BL21*(DE3) cells were used as producers, and purification was carried out by the chromatography method. The combination of silicon wires with protein molecules was carried out by layering under laboratory conditions, followed by drying. The resulting hybrid material was studied by scanning electron microscopy and X-ray photoelectron spectroscopy. The initial silicon wires array had sharp boundaries on the surface. The diameter of the silicon wires was about 100 nm, while the distances between the wires can vary widely, reaching several hundred nanometres or be less than 100 nanometres, depending on the formation conditions, in the absence of noticeable transition layers. The pores formed in this way are available for filling with protein during deposition. The effectiveness of using the scanning electron microscopy method to study the morphology of the hybrid material “silicon wires – bacterial protein Dps” as well as X-ray photoelectron spectroscopy method together with ion etching for the investigation of the composition and physico-chemical of the hybrid material was demonstrated. Complementary results have shown that the molecular culture, which is a solution of oligomers of the recombinant Dps protein of E.coli bacterial cells, can penetrate deep into the pores of the silicon wires array with an extremely developed surface. The possibility of the control of the filling of silicon wires arrays by varying the pore morphology and other modes of formation of structuresand their surface has been demonstrated. The obtained data can be used to study the possibilities of the functionalization of the developed surface of silicon wires by their driven coating with controlled delivery of biohybrid material.

Stabilization of a Carbon Support by Surface Oxygen with Respect to Nitrogen Dioxide in the Pd/HOPG Model System

X-ray photoelectron spectroscopy (XPS) method has been used to study the effect of oxygen on the surface of a carbon support on the result of NO2 interaction with model systems prepared by evaporation of palladium on highly oriented pyrolytic graphite (HOPG). For Pd/HOPG samples with an atomic ratio [O]/[C] ≤ 0.0035, graphite oxidized with the destruction of its structure to a depth of 10–15 graphene layers. In this case, palladium particles remained in the metallic state and penetrated into the subsurface layer of the support due to the deep oxidation of the adjacent carbon atoms. At the atomic ratio [O]/[C] ≈ 0.01–0.02, the result of the interaction changed dramatically. In this case, the HOPG remained stable, and the palladium particles were oxidized to form an oxide. This finding explained the high stability of supported palladium catalysts prepared on Sibunit carbon supports in reactions of oxidation catalysis.

Ordered LiFe5O8 thin films prepared by pulsed laser deposition as an anode material for all-solid thin film batteries

The search for obtaining a Co free low-cost and high-capacity anode thin film material for high energy density all-solid thin film batteries has been driving the increasing innovation and research in Li-ion battery (LIB) technology. In the present case, LiFe5O8 (LFO) thin films are prepared by pulsed laser deposition (PLD) technique and their electrochemical properties, Li ion dynamics, conducting processes at various frequencies and current rates are explored. LFO thin films are seen to crystallize in ordered α -phase with an inverse spinel structure. Chemical state of all the elements is analysed using X-ray photoelectron spectroscopy method. Cyclic voltammeter (CV) study carried out between 0–3 V shows the reduction peak at 0.76 V initially and in the later cycles at 0.86 V with a small shift depicting the exact conversion type behaviour of the LFO thin film. LFO thin film exhibits specific discharge capacity of 25 μAh/cm2 at 10 μA/cm2 current density during the first cycle. Rate capability measurements are carried out at various current densities of 10, 20, 30, 40, 50 and 10 μA/cm2. Li-ion diffusion coefficient during the de-lithiation and lithiation process is seen to be 3.78 × 10−14 cm2/s and 1.41 × 10−13 cm2/s, respectively. CV studies at various scan rates indicates that the mechanism of Li+ storage is dominated by a diffusion-controlled process at low scan rates and with increasing scan rate it becomes a surface-controlled process. Electrochemical impedance studies at various frequencies shows the decrease in charge transfer resistance with increasing cycles. Combined structural, chemical, electrochemical and impedance studies of LFO thin films indicates that these films can be employed for fabricating Co and Ni free all-solid thin film Li-ion batteries for energy storage applications.

A paradigm increase in adsorption efficiency during separation of some styrylpyridinium dyes from organic media using graphene oxide modified silica (GOMS) scaffold

Graphene oxide modified silica (GOMS) has been prepared to study the adsorption of some cationic styrylpyridinium dyes in organic solvent media of variable polarities. GOMS is privileged with very unique surface structure having graphitic network and oxygen functionalities. The unmodified silica, GOMS and dye adsorbed GOMS samples have been characterized by Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) methods. Effects of various optimized conditions like temperature, contact time, adsorbate concentration and adsorbent dosages have been analysed and the kinetic and thermodynamic studies have been correlated with relevant experimental data to reach at a conclusion. The adsorption follows Freundlich isotherm model. The impacts of substituents present on the adsorbate molecules and polarities of the solvents have been discussed to understand the adsorption phenomenon. A suitable modelling has been done to demonstrate the adsorption mechanism from the experimental findings.

Investigation of the Electrochemical Behaviour of Al Current Collector Material Polarised Highly Anodically and Located in Butyltrimethylammonium Bis(trifluoromethylsulfonyl)imide Room-Temperature Ionic Liquid

The electrochemical behaviour of Al, used as a current collector in supercapacitors and in Li-ion and Na-ion electrochemical power sources, was investigated for the first time using the in situ soft X-ray photoelectron spectroscopy (XPS) method, collecting the information directly at the electrolyte-covered Al current collector polarised electrochemically at high anodic potentials. Cyclic voltammetry, electrochemical impedance spectroscopy, and synchrotron in situ soft XPS methods were applied to collect physical and electrochemical information characterising the electrochemically polarised Al-current-collector RTIL interface soaked into the butyltrimethylammonium bis(trifluoromethylsulfonyl)imide (N4111(TFSI)) room-temperature ionic liquid. The obtained data show the start of intensive oxidation processes, including aluminium oxidation and the formation of an insoluble Al(TFSI)3 surface layer in N4111(TFSI) at E ≥ 3.0 V (vs. Ag-QRE). Very intensive electro-oxidation of TFSI− anions at E ≥ 6.5 V (vs. Ag-QRE) has been observed. CV data indicate that the electrochemical oxidation of once-activated Al is possible in N4111(TFSI) at 1.1 V < E < 1.6 V (vs. Ag-QRE). Therefore, the oxidation of Al starts at E ≥ 2.05 V (vs. Ag-QRE) if the Al surface is modified with electro-oxidation products of TFSI− anions.

Covalent Functionalization of Black Phosphorus Nanosheets with Dichlorocarbenes for Enhanced Electrocatalytic Hydrogen Evolution Reaction

Two-dimensional black phosphorus (BP) has emerged as a perspective material for various micro- and opto-electronic, energy, catalytic, and biomedical applications. Chemical functionalization of black phosphorus nanosheets (BPNS) is an important pathway for the preparation of materials with improved ambient stability and enhanced physical properties. Currently, the covalent functionalization of BPNS with highly reactive intermediates, such as carbon-free radicals or nitrenes, has been widely implemented to modify the material's surface. However, it should be noted that this field requires more in-depth research and new developments. Herein, we report for the first time the covalent carbene functionalization of BPNS using dichlorocarbene as a functionalizing agent. The P-C bond formation in the obtained material (BP-CCl2) has been confirmed by Raman, solid-state 31P NMR, IR, and X-ray photoelectron spectroscopy methods. The BP-CCl2 nanosheets exhibit an enhanced electrocatalytic hydrogen evolution reaction (HER) performance with an overpotential of 442 mV at -1 mA cm-2 and a Tafel slope of 120 mV dec-1, outperforming the pristine BPNS.

The opportunities of using a natural adaptogen from the <i>Galleria mellonella</i> larvae in veterinary medicine

A comparative analysis of the adaptation effects of the Porsolt test of fractionated solutions obtained from the products of the larvae of the large wax moth (Galleria mellonella) on biological systems was performed. The method of X-ray photoelectron spectroscopy determined that in the obtained light fraction of the products of larval life there is a high-energy component of N1s spectra (~402.0 eV) and bond energy for carbon in the C-N bond (~286.0 eV), which indicates the presence of protonated amino groups in the samples. Absorption at 1700 cm-1 can be attributed to the presence of dicarboxylic amino acids (glutamic and aspartic) and other organic acids, which are much less in the heavy fraction. During oral administration of the studied extracts, their multidirectional effect on the intestines of laboratory mice was found. The negative effect of heavy fraction on the microbiocenosis of the intestine by the qualitative composition of the microflora was detected. When the light fraction is used, the intestinal microflora is close to the control. Analysis of the number of leukocytes of the small intestine when the fractions were injected reflected the local immune response of the body. The content of these cells on the mucosal plate of mice injected with the lung fraction was 67.2% higher than that of the control mice (p ≤ 0.05). The content of leukocytes on the own plate of the mucosa of mice injected with the heavy fraction was 2.7 times higher compared to the control, indicating an inflammatory reaction. The difference between the experimental groups is significant (p ≤ 0.001). The comparative effect of the fractions showed that their oral administration had a different effect on the swimming time compared to the control. After 20 days of the experiment, mice injected with the heavy fraction had significantly increased their swimming time compared to the first day (p ≤ 0.05). However, a negative adaptogenic effect compared to the control group is noticeable. A significant difference was found between the results on the 30th day between the experimental groups, which indicates a pronounced difference in the results obtained.

Study of the Evolution of the Surface Properties of ZnO Powders under the Action of Mechanoactivation

At present, the development of semiconductor sensor elements that detect hazardous oxides (CO, CO2) is an urgent scientific and technical task. As a rule, wide-gap metal oxides, such as ZnO, CuO, are used as a sensor matrix. Today, there are a large number of approaches to the synthesis and modification of gas-sensitive semiconductors with the possibility of sensitivity to carbon monoxide and carbon dioxide. The state of the environment and the forms of morbidity that occur in this area. The ultimate goal of the study is to find the optimal conditions for the mechanical grinding of zinc oxide in order to achieve the maximum value of the chemoresistive response. In this paper, we studied the patterns of evolution of defects and chemical features of the surface under the action of mechanoactivation in the attritor. Using the X-ray photoelectron spectroscopy (XPS) method, we studied samples ground for 1, 3, and 5 hours using an attritor in an isopropyl alcohol without additional chemical treatment. Deconvolution was carried out by subtracting the Shirley background and then fitting the peak to the Voigt functions, which have a mixed character of Gauss and Lorentz. As a result, it was found that the ratios between the elements and their phases correlate with the stoichiometry of the sample.

Mechanism, behaviour and application of iron nitrate modified carbon nanotube composites for the adsorption of arsenic in aqueous solutions

In this study, ferric nitrate modified carbon nanotube composites (FCNT) were prepared by isovolumetric impregnation using carbon nanotubes (CNTs) as the carrier and ferric nitrates the active agent. The batch experiments showed that FCNT could effectively oxidize As(III) to As(V) and react with it to form stable iron arsenate precipitates. When the dosage of FCNT was 0.1 g·L–1, pH value was 5–6, reaction temperature was 35 °C and reaction time was 2 h, the best arsenic removal effect could be achieved, and the removal rate of As(V) could reach 99.1%, which was always higher than 90% under acidic conditions. The adsorption results of FCNT were found to be consistent with Langmuir adsorption by static adsorption isotherm fitting, and the maximum adsorption capacity reached 118.3 mg·g−1. The material phase and property analysis by scanning electron microscopy, Brunauer–Emmett–Teller, Fourier transform infrared spectoscopy, X-ray photoelectron spectroscopy and other characterization methods, as well as adsorption isotherm modeling, were used to explore the adsorption mechanism of FCNT on arsenic. It was found that FCNT has microporous structure and nanostructure, and iron nanoparticles are loosely distributed on CNTs, which makes the material have good oxidation, adsorption and magnetic separation properties. Arsenic migrates on the surface of FCNT composites is mainly removed by forming insoluble compounds and co-precipitation. All the results show that FCNT treats arsenic at low cost with high adsorption efficiency, and the results also provide the experimental data basis and theoretical basis for arsenic contamination in groundwater.