Increase In Specific Surface Area Research Articles

Comparison studies: The aging character of mask melt blown layers, polypropylene, and polyethylene terephthalate and their adsorption behavior for tetracycline hydrochloride

Melt-blown layer as a crucial component in medical surgical masks could release microplastics (MPs) into the environment after discarding. This study investigated the aging characteristics of the mask melt-blown layer, polypropylene (PP) and polyethene terephthalate (PET) MPs, as well as compared the adsorption capacity of tetracycline hydrochloride (TCH) on the virgin and aged MPs to gain adsorption mechanism. The carbonyl index (CI) index and two-dimensional correlation spectroscopy (2D-COS) analysis showed that the melt blown layer had the lower degree of aging than PP. Compared with the virgin PP and PET, the main reason for the lowest adsorption capacity of TCH on the virgin melt blown layer was that its unique dense microchannel structure led to the strongest hydrophobicity. The virgin PP and PET which had different chemical structures exhibited similar adsorption capacity of TCH. The adsorption of TCH on the MPs was physisorption, which was both controlled by diffusion, partitioning interaction and pore filling. The increase in the adsorption capacity of TCH on the aging MPs was attributed to the increase of hydrophilicity, pore size and specific surface area. In addition, the influence of environmental factors on the adsorption of TCH were discussed. Allover, this research provided comprehensive insights into the enrichment behavior associated with mask melt-blown materials in aquatic environments, and offered valuable data to support the investigation of the desorption behavior between MPs and antibiotics on organisms.

Development of sulfhydryl grafted hierarchical porous geopolymer for highly effective removal of Pb (II) from water

Geopolymers have captured increasing attention in the adsorption of lead ions due to their zeolite-like three-dimensional network structure, and several advantages such as low cost and environmental friendliness. However, their adsorption performance is limited by a small specific surface area and fewer adsorption sites. In this study, a metakaolin-based geopolymer was first pretreated with different concentrations of nitric acid to increase the porosity and surface area. Subsequently, the sulfhydryl functional group was grafted onto the above hierarchical porous geopolymer, which is a inorganic material with multistage pore structure. The result of N2 adsorption and desorption results demonstrated that an increase in specific surface area and number of grafting sites for sulfhydryl groups with increasing acid concentration when the highest nitric acid concentration used is 5 mol/L and acid treatment time is for 5 h. The specific surface area of the fabricated geopolymers was as high as 343.87 m2/g and the concentration of silanol groups reached 4.46 mmol/g at 3 mol/L acid concentration. The maximum Pb2+ adsorption quantities for SH-1HGeo, SH-2HGeo, and SH-3HGeo samples were 173.2 mg/g, 239.8 mg/g, and 386.3 mg/g, respectively. The adsorption processes were in accordance with the pseudo-second-order kinetic model and the Langmuir models, indicating that the Pb2+ adsorption on the sulfhydryl grafted hierarchical porous geopolymer was mainly chemisorption and monolayer adsorption. The contribution of different Pb2+ adsorption mechanism on geopolymer was ion-exchange, while that on SH-3HGeo was functional group complexation.

Bi2O2S topological transformation and in-situ regrowth of [hk1]-oriented SbBiS3-xSex 2D skeleton structure for construction of efficient quasi-two-dimensional Sb2S3-xSex-based heterojunction photoanodes

Antimony chalcogenides (Sb2S3-xSex), as one of the promising light-absorbing materials in optoelectronic energy storage devices, has attracted widespread attention in recent years. Of particular note, its crystal structure consists of the one-dimensional [Sb4S(Se)6]n ribbons with efficient carrier transport efficiency along the [hk1] direction. In this paper, with the aid of the topological transformation of the layered material Bi2O2S, the SbBiS3-xSex bimetallic alloy with 2D skeleton structure was induced to grow in situ, and the conversion of Sb2S3-xSex preferred orientation from [hk0] to [hk1] was realized. The corresponding results showed that 2D skeleton structure was conducive to the construction of photo traps and the increase of electrochemical specific surface area. In addition, Bi2O2S acted as an electron transport layer (ETL) to further promote the migration of photogenerated carriers. At 1.23 V vs. RHE, the photocurrent density of quasi-two-dimensional Bi2O2S/SbBiS3-xSex nanosheet photoanode was as high as 6.41 mA cm−2, which was 7.5 times that of pure Sb2S3-xSex, and the peak value of IPCE could reach 40.93%. This work undoubtedly opens up a new avenue for the designing high-efficiency antimony chalcogenides photoelectrodes.

Improvement of Metal-Doped β-TCP Scaffolds for Active Bone Substitutes via Ultra-Short Laser Structuring.

Various efforts have been made to develop antibacterial biomaterials capable of also sustaining bone remodulation to be used as bone substitutes and reduce patient infection rates and related costs. In this work, beta-tricalcium phosphate (β-TCP) was chosen due to its known biocompatibility and use as a bone substitute. Metal dopants were incorporated into the crystal structure of the β-TCP, and disks were produced from this material. Magnesium and strontium, as well as copper and silver, were chosen as dopants to improve the osteogenic and antibacterial properties, respectively. The surface of the β-TCP samples was further modified using a femtosecond laser system. Grid and line patterns were produced on the plates' surface via laser ablation, creating grooves with depths lower than 20 μm and widths between 20 and 40 μm. Raman and FTIR analysis confirmed that laser ablation did not result in the degradation or phase change of the materials, making it suitable for surface patterning. Laser ablation resulted in increased hydrophilicity of the materials, as the control samples (non-ablated samples) have WCA values ranging from 70° to 93° and become, upon laser ablation, superwicking surfaces. Confocal measurements show an increase in specific surface area of 50% to 200% compared to the control. Overall, the results indicate the potential of laser ablation to improve the surface characteristics of β-TCP, which may lead to an improvement in the antibacterial and osteogenic properties of the produced materials.

High response to formaldehyde gas and ppb-level detectability of nanoparticle Cr2O3/ porous cubic ZnSnO3 composites p-n heterojunction gas sensor

A series of chromium trioxide/zinc metastannate (Cr2O3/ZnSnO3) composites with different ratios were prepared via a simple two-step hydrothermal and high-temperature sintering method. The samples underwent characterization and analysis to assess their micromorphologies, elemental distributions, chemical compositions, and specific surface areas. Furthermore, gas sensing properties were evaluated through experiment. Results showed that the cubic ZnSnO3 block in Cr2O3/ZnSnO3 was in close contact with the surface of nanoparticulate Cr2O3 and the specific surface area increases. Its primary elements are Zn, Sn, Cr, and O. The 15 wt% Cr2O3/ZnSnO3 sensor exhibited an optimal operating temperature of 175 °C, 75 °C lower than that of pure ZnSnO3 (250 °C). The 15 wt% Cr2O3/ZnSnO3 sensor exhibited the best sensing performance for formaldehyde gases with a concentration of 50 ppm. It exhibited a response of 37.8 and could detect ppb-level concentrations of formaldehyde (limit of detection = 612 ppb). Additionally, Cr2O3/ZnSnO3 showed good selectivity for formaldehyde in the presence of six gases, that is, acetone, formaldehyde, methanol, ethanol, ammonia, and carbon monoxide. Cr2O3/ZnSnO3 exhibited good short-term repeatability and long-term stability. Because of the excellent performance of Cr2O3/ZnSnO3 composites, they have broad application prospects in formaldehyde gas detection.

Biochar obtained from alkaline earth metal-treated mushroom residue: Thermal behavior and methyl orange adsorption capability

To achieve the resource utilization of edible fungi residue and obtain efficient adsorbents for treating dyeing wastewater, biochars were prepared from mushroom residue (MR) with the introduction of alkaline-earth metals (AEMs) and used for methyl orange (MO) wastewater treatment. The thermal behavior of the AEM-treated MR was analyzed using thermogravimetric analysis. The physicochemical properties of the biochars obtained from AEM-treated MR (MRCs) were characterized using Fourier transform infrared spectroscopy, laser particle size analyzer, N2 adsorption/desorption, and scanning electron microscopy. The adsorption performance of MRCs on MO was also investigated. The involvement of AEMs was found to obviously move the main pyrolysis zone of MR to a low temperature region and reduce the temperature corresponding to the maximum weight loss rate and activation energy, which is highly dependent on the concentration of AEMs, the anion and cationic species of the AEMs. Moreover, the addition of AEMs resulted in a decrease in oxygen-containing functional groups (-OH, CO, or C–O), a weakening of surface negative charges, an enhancement in aromatic functional groups, and an increase in specific surface area of the MRCs. The adsorption performance of MO on MRCs was significantly improved with the introduction of AEMs as well. Among them, MR pre-treated with 5 mmol/g MgCl2 (MR-MgCl2-5) shows the lowest temperature corresponding to the maximum weight loss rate and the lowest activation energy of 278.52 °C and 4.28 kJ/mol, respectively. The biochar prepared from MR-MgCl2-5 under 400 °C (MR-MgCl2-5-400C) has the weakest surface negative charge and the highest adsorption capacity for MO. The adsorption isotherms, adsorption kinetics, and thermodynamic analysis results showed that the adsorption of MO on MR-MgCl2-5-400C was a spontaneous, chemically dominant monolayer adsorption, with a theoretical maximum adsorption capacity of 81.30 mg/g. This study suggests that AEMs treatment, especially with 5 mmol/g MgCl2, can readily transform edible fungi residue into a low-cost, high-efficient dyeing wastewater adsorbent.

Removal of Methylene Blue by adsorption onto natural and purified clays: Kinetic and thermodynamic study

The present work explores the optimization of experimental conditions for the adsorption of the organic cationic dye methylene blue (MB) by natural and purified clays. The adsorption capacities of samples were determinate to evaluate the efficiency of the purification process. At first, we performed mineralogical and textural analysis of the clay minerals, namely, smooth clay (SC), rigorous clay (RC) and bentonite clay (BC), using various techniques, particularly, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and X-ray fluorescence (XRF). The characterizations data showed that SC and RC are mainly composed of smectite associated with kaolinite, illite and chlorite. While BC is considered a mesoporous and swelling clay with smectite as the major component. The cation exchange capacity (CEC) was determinate as a 6.30 meq/100 g, 10.69 meq/100 g and 32.64 meq/100 g for SC, RC and RC natural samples respectively. It was noticed that the CEC as well as the specific surface area increase once the impurities associated with the clay are removed. A preliminary study was carried out to elucidate the influence of different parameters; such as contact time, exchangeable cation, solute concentration, temperature and pH on MB adsorption in aqueous solution by clays. The adsorption equilibrium data were analyzed by the linear and nonlinear forms of the Langmuir and Freundlich isotherm models. The Langmuir isotherm fitted well with the experimental data, and the pseudo-second-order kinetic model represented appropriately the adsorption kinetics of MB dye. Moreover, purified clays showed improved adsorption capacity for MB compared to pristine ones: 147.64; 257.69 and 1383 mg/g versus 128.75; 193.4 and 681.85 mg/g for SC, RC and BC respectively. This is attributed to a suitable specific surface, ion exchange capacity and electrostatic interactions as result of a more adequate texture and composition of our treated clays. The thermodynamic studies reveled negative Gibbs free energy change (ΔG) values (from -6.293 to -18.608 KJ.mol−1), positive enthalpy change (ΔH) values, exceeding 40 kJ/mol and positive entropy change (ΔS) values confirming the spontaneous, endothermic and chemisorption nature of the MB adsorption process. The results show that the tested purified clays are efficient in MB removal and can be used as an alternative to the commercial adsorbents, which are often relatively expensive.

Preparation and effect of additives n-ZnO doped p-NiO Screen printed thick films on Structural and Electrical Properties

Abstract: Zinc oxide (ZnO) doped Nickel oxide (NiO) thick films prepared using glass substrate by screen printing technique successfully. Synthesis of nanoparticles was confirmed using characterisation techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM) and static gas sensing system. The structural properties of the prepared thick films were studied by XRD analysis. The observed prepared thick film shows polycrystalline nature of the films with a cubic structure and crystallite size found to be in the range of 18.21 to 35.44 nm. SEM analysis of prepared films enabled the conclusion that the prepared films are uniform, large crystals and heavily agglomerated particles were observed spherical in shape. Also, with increase in concentration specific surface area increases. The quantitative chemical compositions were analysed by SEM-EDS and it shows nonstoichiometric in nature. The correlation between structural and morphological properties are reported. The prepared thick films of ZnO doped NiO nanoparticles were analysed for electrical parameters namely TCR, activation energy and sheet resistivity, specific surface area were evaluated at different concentration of zinc oxide that assured the prepared material has a semiconducting nature. Electrical characterization results resistivity decreases from 6283.377 to 1972.727 with increase in wt.% concentration of ZnO. Such a prepared film can be used in fabrication of optoelectronic devices.

Synergistic enhancement of hydrogen storage performance of Mg-La-Ni alloy by CeO2@C composite catalyst

An enhanced chemical blowing carburation method was successfully employed to synthesize a CeO2@C composite catalyst. The catalyst comprises highly dispersed CeO2 nanoparticles within a porous carbon matrix, demonstrating a well-developed micropore structure, an ultrahigh specific surface area, and a high density of defects. Various amounts of CeO2@C were mechanically milled with an Mg96La3Ni alloy to investigate its hydrogen storage properties. The results demonstrated that incorporating CeO2@C significantly refined the Mg-based alloy, leading to an increase in both specific surface area and the number of active sites. The addition of CeO2@C greatly enhanced the hydrogen absorption and desorption kinetics of the alloy, with the optimal amount being 5 wt % CeO2@C. At 360 °C, the alloy could absorb 78.1% of its maximum hydrogen capacity within 2 min, and release an equal amount of hydrogen within 5 min, with the desorption activation energy decreasing to 107.33 kJ/mol H2. The incorporation of CeO2@C significantly reduced the desorption activation energy of the alloy while leaving its thermodynamic performance unaffected. The CeO2 nanoparticles and carbon matrix synergistically catalyze the reactions, with the former primarily facilitating nucleation and the latter facilitating hydrogen diffusion. This study offers novel insights into the design of magnesium-based hydrogen storage materials. The enhanced hydrogen storage performance demonstrated in this work shows the potential of CeO2@C modified Mg-based alloys for practical applications in hydrogen fuel cell vehicles, portable power sources, and other hydrogen energy storage systems.

Experimental investigation of gas diffusion kinetics and pore-structure characteristics during coalbed methane desorption within a coal seam

The desorption-diffusion properties of coalbed methane (CBM) are not only the theoretical basis for investigating gas outburst hazards in a coal mine, but also impose a non-negligible impact on CBM recovery performance. In this paper, the pore structure of coal with five different metamorphism degrees was qualitatively and quantitatively characterized with the scanning electron microscopy (SEM) and low-temperature nitrogen gas adsorption (LTNGA) measurements. The isothermal methane ad/desorption experiments were performed with four initial gas desorption pressure scales. Subsequently, the matching degree between eight empirical correlations (ECs) and the measured methane desorption data was determined, and the methane diffusion coefficient (Dfg) was numerically calculated combining with an FGDG (free gas density gradient) diffusion model. Importantly, we evaluated and discussed the sensitivity of pore structure parameters, initial gas desorption pressure, and volatile fraction to Dfg. The results show that pore density distribution differs among coal samples and the pore structure, especially the micropores, is developed better in high-rank coals than in low- and medium-rank ones. Initial gas release velocity increases with an increase in coal rank and decreases negatively with the increasing particle size in an exponential manner. Among the eight ECs, EC-VIII can be applied to more accurately describe gas desorption process during the whole time scale, and its correlation coefficient with the measured data is larger than 0.9900. Dfg increases with an increase in pore volume and specific surface area (SSA), and it is negatively correlated with the average pore diameter. Additionally, Dfg exhibits an asymmetric U-shaped pattern with an increase in the volatile fraction, which is mainly related to the switch between the dominant roles of mesopores and micropores during coal metamorphism. At a lower volatile fraction, the diffusion coefficient is more sensitive to micropores, while, at a higher volatile fraction, mesopores contribute more to the diffusion coefficient.

Facile Room Temperature Synthesis of Precious‐Metal‐Free Coordination Polymer Photocatalyst for Improved Visible‐Light CO2 Reduction

The Pb–S‐based coordination polymer (CP), named KGF‐9, [Pb(tadt)]n (tadt = 1,3,4‐thiadiazole‐2,5‐dithiolate), can selectively convert CO2 into HCOO− (>99%) under visible light, with an apparent quantum yield (AQY) of 2.6% at 400 nm, without a cocatalyst. However, KGF‐9 is an intrinsically nonporous CP, and its small specific surface area (<1 m2 g−1) might hinder the realization of its full potential as a photocatalyst. Herein, facile synthetic routes at room temperature are reported through a solid‐state reaction and a liquid‐phase reaction (LPR) using lead(II) acetate as a precursor. The use of lead(II) acetate promotes the deprotonation of the H2tadt ligand, resulting in a faster coordination reaction, a reduced feature size, and a drastic increase in specific surface area (≈10 m2 g−1). A higher AQY for formate production (5.9% at 400 nm) is found for KGF‐9 prepared via a 60 min LPR. The improved photocatalytic activity of the LPR sample is attributed to the presence of long‐lived charge carriers, which is revealed by time‐resolved microwave conductivity measurements. The results of this study provide a simple but effective strategy toward increasing the activity of CP‐based photocatalysts.

A mild one-step synthesis of sodium pre-intercalated δ-MnO2@CC for flexible high-performance supercapacitors with ultralong cycle life

Cation ion intercalated δ-MnO2 has been considered as a promising candidate for flexible energy storage devices. Herein, we fabricated Na ion pre-intercalated δ-MnO2 immobilized on flexible carbon cloth (CC) for symmetric supercapacitors via a mild one-step cyclic voltammetry (CV) electrodeposition method. Compared to that of NaxMnO2–32 without NH4+additive, NaxMnO2–32-N with NH4+ additive obtained a larger Cs (1208 mF·cm−2) with a 40 % increase and a maintained Cm (208 F·g−1 at 1 mA·cm−2). In addition, NaxMnO2–32-N exhibited more remarkable capacitive behavior and better rate capability. Based on the XPS, BET, TEM and SEM results, the increase of specific surface area, Na+ ion pre-embedded content and deposition mass were deduced to be the dominant role in optimizing electrochemical properties of δ-MnO2. A flexible symmetric supercapacitor was assembled by NaxMnO2–32-N electrodes to evaluate its applications and demonstrated a high energy density of 117.74 μW·h·cm−2 (at a power density of 225 μW·cm−2) and power density of 3375 μW·cm−2 (at an energy density of 12.35 μW·h·cm−2) with good flexibility. Furthermore, it showed excellent capacity retention rate (97 %) and coulomb efficiency (105 %) after 80,000 long-term charging/recharging cycles.

Eulerian investigation of the mechanism of Ultra-low NOx emissions from CFB boilers with finer bed material

Industrial practice has confirmed that decreasing the bed material size substantially diminishes nitrogen oxide (NOx) emissions in coal-fired circulating fluidized bed (CFB) boilers. This reduction allows for compliance with the stringent ultra-low emissions standard (NOx < 50 mg/Nm3@6%O₂, dry) proposed by the Chinese government, all without the need for supplementary denitrification devices. Consequently, it becomes essential to delve into the mechanisms through which particle size, as a gas–solid flow characteristic, directly affects the chemical reaction dynamics within the coal combustion process. Due to the difficulty of field tests, this paper employs the Eulerian-Eulerian numerical method suitable for wide particle size distributions to investigate the impact of bed material particle size on gas–solid flow and NOx concentration. Furthermore, the generalized QC-EMMS drag model is utilized to predict the heterogeneous flow across varying particle size conditions. Industrial test data validated the simulation accuracy, with prediction errors of bed pressure drop, temperature, and NOx emission concentration ranging from 5 % to 8.1 %. The analysis revealed that the particle concentration distribution heterogeneity decreases as the particle size diminishes. The variation trends of NOx with particle size exhibit distinct differences between the lower dense phase region and the upper dilute phase region within the bed. For finer bed material particles, the high NOx concentration generated in the dense phase region experiences a more thorough reduction in the dilute phase region. Through the analysis of material concentration and reaction rate, it is believed that this phenomenon is related to the increased catalytic effect of fine ash particles in the dilute phase region, that is, the reduction in particle size leads to an increase in catalytic specific surface area, enhancing NOx reduction, thus achieving ultra-low emissions at the outlet. These research results provide theoretical support for further development of ultra-low emission coal-fired CFB boilers.

Hydrogen generation by hydrolysis of ultrafine microstructure Mg[sbnd]10Ni alloy wire

This work presents a MgNi alloy wire prepared by a combination of extrusion and multi-pass hot drawing for fast hydrogen generation from aqueous NaCl solution. The results showed that the hydrogen generation rates of the wire were significantly improved compared to the as-cast alloy. The hydrolysis of the MgNi alloy wire produced 820 ml g−1 hydrogen in 16 min and the maximum hydrogen generation rates reached 67.86 ml g−1 min−1 in 3.5 % NaCl solution and at 25 °C. The improved hydrogen production properties can be attributed to the increase in specific surface area and the ultrafine microstructure with highly dispersed submicron Mg2Ni particles of the MgNi alloy wire.

Experimental investigation on the explosion characteristics and flame propagation behavior of aluminum hydride dust

Aluminum hydride (AlH3) dust is a high-capacity hydrogen storage material but is prone to explosion. In this paper, explosion characteristics and flame propagation behavior of AlH3 dust are investigated. The results indicate that the exposure of bare aluminum and the increase of specific surface area lead to the maximum explosion pressure of AlH3 dust being 4 times higher than that of Al dust. The enhancement of heat transfer by hydrogen combustion causes a higher combustion rate, leading to a higher maximum explosion pressure rise rate and flame propagation velocity of AlH3 dust. The thermo-diffusive instabilities and the evolution of hydrogen result in a pulsation flame propagation velocity of AlH3 dust. Combining the explosion temperature calculated by NASA CEA with the explosion residues analysis, the explosion mechanism of AlH3 dust is further revealed. The break of the oxide film and the combustion of hydrogen result in a different explosion mechanism.

Recovery of iron from pyrite cinder by suspension magnetization roasting-magnetic separation method: Process optimization and mechanism study

Pyrite cinder (PyC) is an iron-enriched tailing.Suspension magnetization roasting(SMR) technology can convert hematite into magnetite, the magnetic properties of the product have been improved, and then through the magnetic separation to complete the separation of magnetite and gangue. SMR consumes less energy than the direct reduction process to obtain Fe(M).SMR-magnetic separation is utilized to effectively exploit the iron in PyC. The results showed that the raw ore for PyC has an iron grade of 56.47%, and after SMR-magnetic separation, magnetic concentrate with an iron grade of 63.24% and an iron recovery of 95.05% could be achieved under conditions of a roasting temperature of 480°C, a reductant concentration of 30% (CO: H2 = 1:3), a roasting time of 20min, 1200Oe magnetic field intensity, and a finesse of grinding content of -0.038mm 80%. The analyses of the process mechanism were performed using X-ray diffraction (XRD), vibrating sample magnetometer (VSM), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy as well as fully automatic specific surface and porosity analyzer BET. It was revealed that the transformation of hematite to magnetite took place during the suspension magnetization roasting process, which also contributed to the generation of cracks and pores that led to the increase of specific surface area, total pore volume and average pore diameter.

Effect of Yb2O3@C composite catalyst on hydrogen storage performance of Mg–La–Ni alloy

The present study successfully synthesized a Yb2O3@C composite catalyst using an enhanced chemical blow molding carbonization method. The characterization results showed that the catalyst was highly dispersed in the porous carbon matrix by Yb2O3 nanoparticles. And the catalyst has developed pore structure, high specific surface area and high defect density. Yb2O3@C was mixed with the Mg96La3Ni alloy through ball milling, and the impact of varying amounts of Yb2O3@C on the hydrogen storage performance of Mg96La3Ni was comprehensively investigated. The research findings indicate that the addition of Yb2O3@C notably refines the Mg-based alloy, leading to an increase in both specific surface area and the count of active sites. Furthermore, Yb2O3@C markedly enhances the hydrogen sorption kinetics of Mg96La3Ni, with the most substantial impact noted at a Yb2O3@C content of 3 wt %. Additionally, the incorporation of Yb2O3@C substantially decreases the dehydrogenation activation energy of the alloy, while leaving its thermodynamic properties unaffected. Yb2O3 nanoparticles and the carbon matrix work synergistically to promote both nucleation reactions and hydrogen diffusion. This study presents a novel strategy for enhancing the performance of hydrogen storage materials based on magnesium.

High-performance electromagnetic wave absorption of NiS/Ni0.96S@multi-walled carbon nanotube composites

In this work, composites of heterogeneous nickel sulfide with multi-walled carbon nanotubes (MWCNTs) were prepared by a simple hydrothermal method. The dielectric loss capacity of composite materials is enhanced with the introduction of CNTs. Meanwhile, with the increase of CNTs content, the particle size of nickel sulfide decreases and the specific surface area increases, which is beneficial to enhance the microwave absorption capacity of the sample. The composite with the best microwave absorption performance was obtained by changing the NiS/Ni0.96S@MWCNTs mass ratio. By adjusting the NiS/Ni0.96S@MWCNTs mass ratio to 6:1, the effective absorption bandwidth is 3.76 GHz, corresponding to a thickness of 1.3 mm. Besides, the minimum reflection loss (RL) value was as high as –35.5 dB at 10.0 GHz with the thickness of 2.0 mm. The above results show that the prepared NiS/Ni0.96S@MWCNTs composite has the advantages of thin thickness, light weight, strong absorption and simple preparation, and is a microwave absorbing material with promising applications.

Development of heterogeneous photocatalysis delafossite structured Ag doped Cd-Cu ferrite spinel nanoparticles for an efficient photodegradation process

The photodegradation of sunset yellow dye was efficiently achieved using Ag-Doped Cd-Cu Spinel Nanoferrite as a photocatalyst under ambient circumstances. The method demonstrates economic feasibility, environmental sustainability, non-toxicity, scalability, and the absence of toxic and volatile organic solvents and surfactants. Ag-doped Cd-Cu spinel nanoferrite (Cd0.5Cu0.5-xAgxFe2O4, x = 0.0, 0.1, 0.2, 0.3, 0.4, and 0.5) was prepared using the green co-precipitation method. X-ray diffraction patterns represented the formation of a major spinel phase and a minor delafossite phase. XPS spectra show the multiple variant valences of the constituted elements (Cu+, Cu2+, Cd2+, Ag+, Fe2+, Fe3+, and Fe4+). The Mossbauer spectroscopy measurements confirmed the stability of the delafossite phase. The HRTEM, SEM, and elemental mapping indicated homogenous elemental distributions inside the samples. The prepared nanoparticles exhibited large specific surface areas between 94 and 161 m2/g, indicating their potential applications in chemical and biological fields. The UV–visible light absorption of these materials suggested the possibility of their use as photocatalysts under visible light irradiation. Various effects, such as pH, the concentration of dye, catalyst dose, and the amount of H2O2, were studied. The photodegradability of Sunset Yellow increases with higher silver doping as well as the majority of the delafossite phase due to the increase in specific surface area. The COD reduction is 71.5 % in optimum conditions. The possible photocatalytic degradation pathway of Sunset Yellow was suggested based on GC–MS analysis. A reaction mechanism involving HO• as an effective oxidant was proposed.

The Effect of Different Grinding Technologies on the Mechanical Properties of Portland Cement Depends on the Type of Intensifier

Cement production is currently very energy-intensive, with the grinding process consuming the majority of the total energy in cement production. Therefore, there is a constant search for ways to reduce this amount of energy while maintaining the same grinding efficiency. The main goal of the article is to investigate the effect of grinding intensifiers, which should reduce the energy needed to grind raw materials. Potentially usable technologies in the field of mechanochemical activation are investigated, i.e., high-speed grinding through grinding in a laboratory planetary mill and disintegrator. High-speed disintegrator grinding technology is much more efficient than planetary grinding technology. Already during the first passage through the disintegrator, an increase in the specific surface area from 200 m2/kg to 280 m2/kg was recorded, with an estimated stay of the particle in the grinding space for 3-5 seconds. Using a planetary mill, the particles would have to remain in the grinding chamber for approximately 2 minutes to achieve such an increase in specific surface area. However, with further drops, the efficiency decreases, which is due to the high tendency to aggregation and agglomeration in this milling technology.