Bigger Particles Research Articles

Metal-Ligand Interface and Internal Structure of Ultrasmall Silver Nanoparticles (2 nm).

Ultrasmall silver nanoparticles were prepared by reduction with NaBH4 and surface-terminated with glutathione (GSH). The particles had a solid core diameter of 2 nm as shown by transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS). NMR-DOSY gave a hydrodynamic diameter of 2 to 2.8 nm. X-ray photoelectron spectroscopy (XPS) showed that silver is bound to the thiol group of the central cysteine in glutathione under partial oxidation to silver(+I). In turn, the thiol group is deprotonated to thiolate. X-ray powder diffraction (XRD) together with Rietveld refinement confirmed a twinned (polycrystalline) fcc structure of ultrasmall silver nanoparticles with a lattice compression of about 0.9% compared to bulk silver metal. By NMR spectroscopy, the interaction between the glutathione ligand and the silver surface was analyzed, also with 13C-labeled glutathione. The adsorbed glutathione is fully intact and binds to the silver surface via cysteine. In situ 1H NMR spectroscopy up to 85 °C in dispersion showed that the glutathione ligand did not detach from the surface of the silver nanoparticle, i.e. the silver-sulfur bond is remarkably strong. The ultrasmall nanoparticles had a higher cytotoxicity than bigger particles in in vitro cell culture with HeLa cells with a cytotoxic concentration of about 1 μg mL-1 after 24 h incubation. The overall stoichiometry of the nanoparticles was about Ag∼250GSH∼155.

ZSM-5 zeolite coatings on perlite support for MTO application

ZSM-5 zeolite crystals were grown via an in situ hydrothermal synthesis on perlite supports. In this study, cheap perlite mineral, which mainly contains SiO2 and metal oxides (Al2O3, CaO, MgO), was used as aluminum source and support material for binderless zeolite crystals growth. Hence, this synthesis strategy neither needs the introduction of Al, nor support surface functionalization steps, which may diminish the cost. Besides, the highly porous structure and the big particle size of ZSM-5/perlite composites are beneficial to reduce the pressure drop along the catalyst bed, rendering easier the heat and mass transfer of the products. In addition, the influence of different particle sizes (4–3, 3–1.5 and 1.5–0.5 mm) and quantities (1–3 g) of ZSM-5/perlite without any further modification were successfully evaluated in the Methanol-To-Olefins reaction (MTO). An optimized ZSM-5/perlite structured catalyst exhibited a high stability at full methanol conversion during 14 h on stream, along with a 80% selectivity towards light olefins at 475 °C. In addition, this catalyst still exhibited an excellent catalytic activity at relatively low temperature (350 °C), the methanol conversion remaining 96% after 28 h on stream. Finally, the conversion was maintained at 95% during 8 h on stream at WHSV = 8 h−1 with a propylene selectivity of 38%.

Proton-Assisted Reconstruction of Perovskite Oxides: Toward Improved Electrocatalytic Activity.

Electrocatalysis is indispensable to various emerging energy conversion and storage devices such as fuel cells and water electrolyzers. Owing to their unique physicochemical properties, perovskite oxide materials are one of the most promising water oxidation (OER) catalysts solely comprising earth-abundant elements. Nonetheless, many perovskite oxide catalysts suffer from a number of inherent problems such as the A-site cation segregation on the surface, coarse particles due to agglomeration/sintering, and surface decomposition during catalytic reactions. Besides, the catalytic activity is often incomparable with those of the state-of-the-art catalysts. In this work, we developed a proton-assisted approach to mitigate these common challenges. The protonation via the interaction of oxygen vacancies and water molecules induced the formation of protonic defects and the lattice expansion of the perovskite, leading to the fracture of big particles to yield small nanoparticles. This hydration in an acidic solution also selectively removed the A-site cation segregates and generated a spinel/perovskite heterostructure on the surface. We verified this approach using three typical perovskite OER catalysts including Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF), La0.6Sr0.4Co0.8Fe0.2O3 (LSCF), and La0.75Sr0.25MnO3 (LSM). The processed catalysts showed much improved activity while maintaining their excellent stability, surpassing most of today's OER catalysts based on complex oxides.

Modelling cometary meteoroid stream traverses of the Martian Moons eXploration (MMX) spacecraft en route to Phobos

The Martian Moons Exploration (MMX) spacecraft is a JAXA mission to Mars and its moons Phobos and Deimos. MMX will be equipped with the Circum-Martian Dust Monitor (CMDM) which is a newly developed light-weight (mathrm {650,g}) large area (1,mathrm {m}^{2}) dust impact detector. Cometary meteoroid streams (also referred to as trails) exist along the orbits of comets, forming fine structures of the interplanetary dust cloud. The streams consist predominantly of the largest cometary particles (with sizes of approximately 100,mu mathrm { m} to 1 cm) which are ejected at low speeds and remain very close to the comet orbit for several revolutions around the Sun. The Interplanetary Meteoroid Environment for eXploration (IMEX) dust streams in space model is a new and recently published universal model for cometary meteoroid streams in the inner Solar System. We use IMEX to study the detection conditions of cometary dust stream particles with CMDM during the MMX mission in the time period 2024 to 2028. The model predicts traverses of 12 cometary meteoroid streams with fluxes of 100,mu mathrm { m} and bigger particles of at least 10^{-3},mathrm {m}^{-2},mathrm {day}^{-1} during a total time period of approximately 90 days. The highest flux of 0.15,mathrm {m}^{-2},mathrm {day}^{-1} is predicted for comet 114P/Wiseman-Skiff in October 2026. With its large detection area and high sensitivity CMDM will be able to detect cometary meteoroid streams en route to Phobos. Our simulation results for the Mars orbital phase of MMX also predict the occurrence of meteor showers in the Martian atmosphere which may be observable from the Martian surface with cameras on board landers or rovers. Finally, the IMEX model can be used to study the impact hazards imposed by meteoroid impacts onto large-area spacecraft structures that will be particularly necessary for crewed deep space missions.

Preparation of CaO-SiO<sub>2</sub> Adsorbent for Potential CO<sub>2</sub> Capture via Dry Mixing Method

Calcium-looping technology is defined as one of the most desirable methods of carbon capture, utilization and storage (CCUS). However, because of sintering, rapid deactivation of CaO-sorbents is currently a major barrier to this technology. The stability of calcium based sorbent may be enhance by incorporating them with inert support materials such as MgO, Al2O2, ZrO2 and SiO2. For this study, calcium based sorbent has been incorporate with silica obtained from rice husk ash. CaO-SiO2 sorbents are prepared using physical dry mixing method which is much simpler compared to other available methods. The prepared CaO-SiO2 sorbents were then characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). New crystalline phase, larnite (Ca2SiO4) was detected in XRD patterns and this phase possess good chemical durability and may help to prevent sintering effect of calcium based sorbents and enhance their cyclic capability. CaO-SiO2 sorbent calcined at 700 oC with different grinding times have highest intensity of XRD peak at (104) with element of calcite. Sorbents with different weight composition of CaCO3-RHA were observed to have different surface morphology. SEM images of the sorbent (90wt% CaCO3-RHA) before calcination showed bigger particle size with irregular shape and more porosity. Then, SEM analysis was conducted for samples with different grinding times after calcination. CaO-SiO2 sorbents with 20minutes grinding time exhibited small size of particles with some porosity. Besides that, the particles are well distributed without agglomeration occured. The CaO-SiO2 sorbent calcined at 700 oC sorbents were tested for 20 consecutive carbonation and calcination cycles using Thermogravimetric Analysis (TGA). CaO-SiO2 sorbent treated with 700 oC calcination temperature and 20 minutes of grinding shows better cyclic CO2 sorption capacity.

Experimental study on abrasive recycling in cutting with abrasive suspension water jet

As the only cold high-energy beam machining technology, abrasive water jet cutting has a lot of unique advantages to process a large variety of materials. The main factor restricting its development and application refers to its high processing cost. Abrasive consumption is considered as one of the main costs. Abrasive recycling is an effective way for reducing the cost. In addition, it is also beneficial to environmental protection. Abrasive suspension water jet (ASJ) is more suitable for abrasive recycling than traditional abrasive water jet (AWJ) because ASJ does not use dry abrasives. Based on the idea of strive for the recycling process simple and effective, the abrasive recycling of ASJ was studied in this work. It is found that the recycled abrasives with only big particle impurity being sieved out still have strong cutting ability. An simplified abrasive recovery scheme of ASJ cutting system has been proved to be feasible. With 30% of recharge in each cycle, the abrasive can be fully utilized and its cutting performance can remain basically the same in every reuse cycle of continuously recycling process. The abrasives between 90 and 180 μm are optimal abrasives for the cutting surface roughness, compared with the larger size abrasives; the smaller size abrasives have more negative influence on the surface roughness, which should be concerned in the recycling process.

Numerical Study toward Optimization of Spray Drying in a Novel Radial Multizone Dryer

In this paper, an intensified spray-drying process in a novel Radial Multizone Dryer (RMD) is analyzed by means of CFD. A three-dimensional Eulerian–Lagrangian multiphase model is applied to investigate the effect of solids outlet location, relative hot/cold airflow ratio, and droplet size on heat and mass transfer characteristics, G-acceleration, residence time, and separation efficiency of the product. The results indicate that the temperature pattern in the dryer is dependent on the solids outlet location. A stable, symmetric spray behavior with maximum evaporation in the hot zone is observed when the solids outlet is placed at the periphery of the vortex chamber. The maximum product separation efficiency (85 wt %) is obtained by applying high G-acceleration (at relative hot/cold ratio of 0.75) and narrow droplet size distribution (45–70 µm). The separation of different sized particles with distinct drying times is also observed. Smaller particles (<32 µm) leave the reactor via the gas outlet, while the majority of big particles leave it via the solids outlet, thus depicting in situ particle separation. The results revealed the feasibility and benefits of a multizone drying operation and that the RMD can be an attractive solution for spray drying technology.

Investigation of Ring and Star Polymers in Confined Geometries: Theory and Simulations.

The calculations of the dimensionless layer monomer density profiles for a dilute solution of phantom ideal ring polymer chains and star polymers with arms in a -solvent confined in a slit geometry of two parallel walls with repulsive surfaces and for the mixed case of one repulsive and the other inert surface were performed. Furthermore, taking into account the Derjaguin approximation, the dimensionless layer monomer density profiles for phantom ideal ring polymer chains and star polymers immersed in a solution of big colloidal particles with different adsorbing or repelling properties with respect to polymers were calculated. The density-force relation for the above-mentioned cases was analyzed, and the universal amplitude ratio B was obtained. Taking into account the small sphere expansion allowed obtaining the monomer density profiles for a dilute solution of phantom ideal ring polymers immersed in a solution of small spherical particles, or nano-particles of finite size, which are much smaller than the polymer size and the other characteristic mesoscopic length of the system. We performed molecular dynamics simulations of a dilute solution of linear, ring, and star-shaped polymers with , 300 (360), and 1201 (4 × 300 + 1-star polymer with four arms) beads accordingly. The obtained analytical and numerical results for phantom ring and star polymers are compared with the results for linear polymer chains in confined geometries.

Uncertainty Measurements in Chemically Synthesized Stable Uniform Sized Gold Nanoparticles for TEM/HRTEM Calibration

The accuracy of an electron microscope depends on the magnification and resolution of the microscope. Hence in order to achieve high accuracy measurement results from the electron microscopic examination, a standard specimen is required to calibrate the transmission electron microscope (TEM). In the present work, gold nanoparticles of uniform size with narrow particle size distribution were synthesized with an aim to use them as reference material (RM) for TEM/high resolution TEM calibration and then release them in market as Bhartiya Nideshak Dravya (BND). As synthesized gold nanoparticles at 20 ± 2 C temperature and 45± 5% relative humidityand the standard sample were characterized by using HRTEM, model: FEI-Tecnai F30 G2 STWIN at suitable magnification and areas. Both images exhibit spherical shaped nanoparticles with size varying in the range from (15.35-20.15 nm) and (5.10 -7.70 nm) respectively. Stability in particles size of the chemically synthesized gold nanoparticles was studied for a period of one year time span using UV-Visible spectrometer. TEM/HRTEM measurements were carried out in automated mode under similar experimental and environmental conditions at different magnifications to get accurate particle size. Overall uncertainty is estimated in small and big size particles as per standard GUM document guidelines.

Influence of microbubbles on the production of spray-dried inhalable particles

The aim of this work was to study the effect of gas microbubbles on the production of particles suitable for inhalatory administration by a spray drying technology. An antiasthmatic model drug (sodium cromoglycate) was selected in order to evaluate the effect of different gases (air, CO2 and N2) and spray drying operating conditions on the particles aerosolization performance. To this end, gas supersaturated aqueous drug solutions were obtained in a pressurized vessel and then processed by spray drying. The process yield, morphology, size, bulk and tap densities, moisture content and aerosolization properties of the particles were evaluated. The presence of microbubbles in the spray drying feed led to powders with smaller mean geometric sizes than particles obtained without bubbles. The gas-water solubility emerged as a key parameter to obtain inhalatory particles with good aerosolization properties. High water-soluble gases led to bigger particles, while low soluble ones allow to produce smaller particles. The use of air (with an intermediate water solubility respect to CO2 and N2) and an adequate set of spray drying operating conditions allowed to obtain sodium cromoglycate particles with superior aerosolization properties than a commercial formulation. Overall, a novel, simple and low-cost method to produce inhalatory particles with excellent aerosolization properties was developed by supersaturating the spray drying liquid feed without using pore-forming agents during the production step, or carriers in the final formulation.

Off-line washing effectiveness on a multistage axial compressor

The interaction between gas turbines and airborne particles determines detrimental effects on the performance, efficiency, and reliability of the power unit. When it is possible, the interaction is reduced by the use of inlet separators and filtration systems. In an aero engine, these barriers are difficult to implement, and only bigger particles (usually greater than 10 μm) are separated from the airflow. Small units, especially those equips helicopters, are usually affected by fouling issues, especially when the aircraft is employed in harsh environments such as firefighting and rescue activities. To recover this contamination, the unit is washed after the mission by ground operations to restore the unit performance by removing the deposits. This operation occurs during a sub-idle unit operation, and the washing process has to be effective when the engine operates in this off-design condition. In this paper, the evaluation of the washing performance during a sub-idle unit operation is carried out. The compressor unit is a multistage axial compressor that equips the Allison 250-C18 engine. The washing operation was performed by water, and a sensitivity analysis is carried out to discover the capability of water droplets to remove the contaminants. The experimental analysis involves the contamination of the unit by micro-sized soot particles and a washing operation by micro-sized water droplets. These experimental results are compared to numerical simulations to discover the effects of the washing operation on a small power unit during sub-idle operating conditions. The off-design regime imposes a specific evaluation of the proper setup of the washing strategy: flow separations involve wider regions in the compressor unit, and the removal capability is strongly related to the droplet path through the stages. The results show how in the off-design washing operation, the droplet diameter has greater importance than the water flow rate for reducing the deposits over the compressor stages.

Experimental investigation of segregation of granular mixtures during heap formation

The present study is on segregation of granular mixtures during heap formation in a quasi two-dimensional rectangular bin where binary mixture of a specified composition is poured intermittently into the auxiliary hopper and then allowed to pass through the gap (k = 10 mm) between the divider and the plate and finally settle on to the heap. The profiles of number fraction of big particles are plotted along the flow directions to study the segregation phenomena for surface profile. It shows that larger particles travel more distance and smaller particles settle near the pouring point for all cases studied.

Influence of Ni (II) oxime complex coupled with the combination of diverse sized ZnO nanoparticles on Photovoltaic Performance

The one side selective synthesis of quinoline carboxylic acid oxime complex was carried out successfully. The as-prepared quinoline carboxylic acid oxime complex was complexed with nickel (II) salts to form nickel (II) oxime complex. These complexes were further adsorbed onto ZnO films containing ZnO nanoparticles of various sizes. ZnO films containing a diverse proportion of ZnO nanoparticles were investigated to enhance the photovoltaic efficiency of the dye-sensitized solar cell. The as-synthesized complex was characterized by scanning electron microscopy (SEM), Ultra violet visible spectroscopy (UV-vis), Fourier Transform Infrared Spectroscopy (FT-IR) spectroscopy, 1Hydrogen Nuclear magnetic resonance spectroscopy (1HNMR), Liquid chromatography coupled with mass spectrometry (LC-MR), Brunauer–Emmett–Teller (BET), and Attenuated total reflection Infra-red spectroscopy (ATR-IR). The combination of large and small ZnO nanoparticles has significantly improves the photovoltaic efficiency. The optimum mixing ratio for the best performance (0.127%) of a dye-sensitized solar cell is achieved by mixing the small: large ZnO particles in a ratio 60:40. The increased efficiency is due to the harvesting of light caused by scattering effect from larger sized ZnO particles. The ZnO layer consisting of smaller particles which are very next to the ZnO bigger particles makes a good electronic contact between film electrode and the Indium-doped tin oxide glass substrate resulting in the increases in the dye molecules adsorption. The over-layered, large-sized ZnO particles enhance the light-harvesting by light scattering effect. Compared to the other mixtures of ZnO films, there is a decrease in the photovoltaic performance of the solar cell when ZnO particles (small and large in a ratio 1:1) were adsorbed onto the Ni (II) oxime complex, which are caused due to the decrease in the surface area and dye aggregation.

Analysis of Indoor Air QualityBased on Low-Cost Sensors

According to WHO, indoor and/or outdoor air pollution is one of the main contributors to over two million premature deaths each year. As most of the human’s life is spent indoor, Indoor Air Quality (IAQ) - an air quality inside of a building represented by pollutant concentration and thermal condition - is one factor that needs to be concerned to sustain healthy living. In this research, we developed an Internet of Things (IoT)-based IAQ monitoring device using low-cost sensors that measure the concentrations of Carbon Dioxide (CO2), Oxygen (O2), and Particulate Matter (PM2.5). This device connects to an Android application to further observe these parameters inside two practicum laboratories in Telkom University, Bandung, for a total duration of six weeks. The location is surrounded by urban air pollution, particularly industrial activities, and residential waste burning. We also have sites of outdoor air quality monitoring system for simultaneous measurement. The environmental conditions were observed under no human activities, human intervention, and indoor plants' influence (i.e., Dieffenbachia sp.). Results show that pollutant concentrations are considerably influenced by outdoor conditions, occupancy level, and ventilation rate. Indoor plants can reduce CO2 concentrations inside the room (21-47%). On the other hand, there is no clear evidence that PM2.5 mass concentrations were affected by human activities. The bigger particles (PM >2.5 microns) probably were the ones induced by occupants during practicum. Therefore, using low-cost sensors is trustworthy to monitor IAQ for a better quality of life.

Experimental study on hydrogen reduction of industrial fines in fluidized bed

ABSTRACT A novel setup of fluidized bed was developed to study the reduction of iron oxides by pure hydrogen. The setup enabled the introduction of powder directly to pure hydrogen atmosphere at experimental temperature. The arrangement was to minimize the experimental uncertainties due to gas switching. Hematite and magnetite powders were studied in the temperature range of 768-888 K. Reduction rates of the two powders were found to be similar. For both powders, the reduction rates were very high before the O/Fe ratio reached 0.5. Thereafter, the reduction was sluggish. SEM analyses revealed that the later stages of reaction was controlled by diffusion through the product layer on bigger particles, irrespective of the type of oxide powder. The results have indicated that both hematite and magnetite powder could be employed in fluidized bed. The results have also suggested that process optimization is essential regarding the sluggish reaction below 0.5 O/Fe ratio.

Investigation of electron transfer between single plasmon and graphene by dark field spectroscopy

We investigated the electron transfer time between single plasmonic gold nanoparticles and graphene with our home-build spectral imaging dark-field microscope. The process of electron transfer is supposed to be shuttling of hot electrons on the nanoparticle-graphene interface, resulting in a slight broadening of the scattering spectrum. For detecting the minor spectrum broadening, we firstly characterized our setup systematically and then calibrated its intrinsic error. We found the mechanism of a common but normally neglected setup error, scattering spectrum broadening, which is caused by the bandwidth of the incident light and could exist in most fast dark-field microscopy setups. We corrected the linewidth of plasmon scattering spectra theoretically by both numerical and analytical solution, and then realized it experimentally by tuning the bandwidth of the incident light. After calibration, we revisited scattering spectra of 700 small aspect ratio nanorods on glass and monolayer graphene revealing a typical 14.3 meV linewidth broadening. Furthermore, we measured four other kinds of gold nanoparticles on glass, mono- and bilayer graphene for deeper understanding of the electron transfer. A common linewidth broadening is found for each kind of particle agreeing well with previous theory. However, an unconventional linewidth narrowing is also discovered for big particles whose resonance wavelength is close to the near infrared region. It implies a competitive mechanism in the electron transfer process which could not only increase the damping of small particles, causing a linewidth broadening, but also simplify the electric field pattern for big particles, leading to a linewidth narrowing, according to our Mie theory simulation.

Experimental investigation of damage formation and material removal in ultrasonic assisted grinding of RBSiC

Ultrasonic assisted grinding (UAG) has been considered as a prominent processing method of the reaction bonded silicon carbide (RBSiC). To improve the knowledge of UAG process, both conventional grinding (CG) and UAG were used to process the RBSiC for in-depth investigation. Grinding forces, surface topographies, and subsurface damages during CG and UAG were compared. Furtherly, the ground surface was analyzed on aspects of both topographical characteristics and material removal mechanism. The results indicated that the removal of material is mainly achieved by the intersections of cracks initiated from both big SiC particles and mixture area of silicon matrix and small SiC grains. The crack propagation during UAG was more intensified due to the ultrasonic impact, which results in higher efficiency of machining RBSiC.

Influence of alloying on the catalytic performance of Ni–Al catalyst prepared from hydrotalcite-like compounds for methane decomposition

Cobalt-, iron-, and copper-substituted nickel-aluminum hydrotalcite-like compounds (Ni2.7Co0.3Al, Ni2.7Fe0.3Al, Ni2.7Cu0.3Al HTlcs) have been synthesized and used as precursors to prepare Ni–Co, Ni–Fe, and Ni–Cu alloy catalysts for methane decomposition. The catalysts before and after reaction were characterized with various techniques including XRD, H2-TPR, HAADF-STEM-EDX, SEM, TEM, and Raman. The characterization results indicate that upon calcination HTlcs are transformed into a mixed oxide solid solution, where cobalt, copper, and iron ions are incorporated into the nickel oxide, and the reduction treatment leads to composition-uniform alloy particles. In methane decomposition at 600 °C, alloying Ni with Co, Fe, and especially Cu is found to enhance the catalytic life and carbon yield. The order of activity is Ni2.7Cu0.3Al >> Ni2.7Fe0.3Al > Ni2.7Co0.3Al > Ni3Al in terms of carbon yield, highlighting that Ni–Cu alloying is the most effective. Besides, Ni–Cu alloying remarkably changes the carbon morphology, giving carbon nanofibers as the main product. TEM and STEM measurements suggest that Ni–Cu alloy particles are readily aggregated into big particles (>60 nm) under the reaction conditions, which may be responsible for the significant effect of Ni–Cu alloying.

Wear of Quenched and Aged Cu–Be Alloy at Current Transfer

Sliding friction tests were carried out on quenched and aged unlubricated samples of C17200 beryllium bronze with and without the current flow through frictional contact. It is shown that the quenched samples are exposed to corrosion-mechanical wear by the oxidation of the friction surface, followed by the separation of wear particles as ultradispersed oxides. The wear of the aged sample is attended by the separation of big wear particles as a result of adhesive interaction. The application of electric current in sliding allows reducing the wear resistance of quenched bronze to 109.3 h/g as compared to the 143.9 h/g of the sample tested without current. The application of electricity results only in a negligible reduction in the wear resistance of the aged bronze samples from 86.6 to 77.8 h/g.

Fungal-induced modification of spontaneously precipitated ochreous sediments from drainage of abandoned antimony mine

Iron-containing spontaneously precipitated ochreous sediments serve as natural scavengers of various migrating elements and in this way contribute to removal and immobilization of potentially hazardous elements especially from mine drainage outflows. On the other hand, presence of filamentous fungi in their surroundings triggers biotransformation and contributes to the mobility of these elements. Three groups of samples of spontaneously precipitated ochreous sediments from an abandoned antimony mine in Poproč, Slovakia were studied: as-collected, sterilized at 95 °C for 30 min, and exposed to incubation with filamentous fungus Aspergillus niger which is frequently found in soils. Employing chemical analyses have determined the content of Fe, As, Sb, and Zn in the samples as well as their mobilization among the non-dissolved residue, culture medium of the fungus and/or its biomass. Significant degree of biovolatilization of antimony was unveiled. Speciation of iron was performed by 57Fe Mössbauer spectroscopy performed in a wide temperature range 300–4.2 K and external magnetic field of 6 T. Hyperfine interactions between 57Fe nuclei and their electronic shells have revealed superparamagnetic behavior characteristic for small particles. Their blocking temperatures of 46, 53, and 40 K, respectively, indicate a dependence of the size of the particles upon the sample treatment. While sterilization has supported their growth, incubation with fungus has changed their chemical environment and removed mainly bigger particles.