Control Of Particle Size Research Articles

Recovery and Size-Tuning of Amorphous Silica from Geothermal Scales in Batangas, Philippines

Scale deposits in geothermal power plants are well-known potential sources of minerals. Extensive research in mineral recovery is crucial due to the considerable variability in scale composition and geochemistry based on location. Geothermal scales from Batangas, Philippines, were used to synthesize size-modified amorphous silica (SiO2) via sol-gel method. Initial analyses employing x-ray fluorescence spectroscopy (XRF), total dissolved solids (TDS), electrical conductivity (EC), and pH measurements confirmed that the scale is rich in silica and salts at neutral pH. Then, the effect of varying scale concentration, precipitation pH, and aging time on the particle size distribution of recovered amorphous silica were investigated. Dynamic light scattering (DLS) for particle size analysis (PSA) revealed that the sample with 2.5% (w/v) scale precursor in NaOH and precipitated until pH 10 had the lowest average cumulant diameter (1.66 μm). Moreover, the synergy of precipitation pH and aging time was found to significantly affect the polydispersity index and cumulative diameter of precipitated SiO2 based on 23 factorial ANOVA at 0.05 significance level. X-ray diffractometry (XRD), Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) confirmed that the precipitates were amorphous SiO2 with spherical morphology. This study proves the viability of utilizing geothermal scales from Batangas, Philippines for the synthesis of amorphous SiO2 with controlled particle size, which is a potential filler for composite materials.

Green-synthesis of silver nanoparticles AgNPs from Podocarpus macrophyllus for targeting GBM and LGG brain cancers via NOTCH2 gene interactions

Brain tumors, particularly Glioblastoma Multiforme (GBM) and Low-Grade Gliomas (LGG), present significant clinical challenges due to their aggressive nature and resistance to conventional treatments. Traditional therapies such as surgery, chemotherapy, and radiation are often limited in efficacy, necessitating novel therapeutic strategies. Nanotechnology, particularly the use of silver nanoparticles (Ag NPs), offers a targeted and potentially more effective approach. This study focuses on the green synthesis of Ag NPs using Podocarpus macrophyllus leaf extract as a reducing agent. The synthesized Ag NPs were characterized for their physicochemical properties, demonstrating a controlled particle size of 13 nm as determined by scanning electron microscopy (SEM). Fourier-transform infrared (FTIR) spectroscopy confirmed the presence of functional groups, and energy-dispersive X-ray (EDX) spectroscopy revealed that silver constituted approximately 90% of the nanoparticle composition. The Ag NPs exhibited promising biological activity, including 90% free radical scavenging (antioxidant) activity, 99.15% inhibition of protein denaturation (anti-inflammatory activity), and 90.56% inhibition of alpha-amylase (anti-diabetic activity). Additionally, the nanoparticles displayed significant anti-hemolytic (89.9% inhibition) and antimicrobial activities, with a 20 mm inhibition zone against Staphylococcus species. Computational analyses further indicated that the NOTCH2 gene, which is upregulated in LGG and GBM, may interact with Ag NPs, suggesting their potential in brain cancer therapy. The green synthesis approach offers a sustainable and bioactive method for producing Ag NPs, underscoring their therapeutic promise for treating GBM and LGG.

Synthesis and Characterization of Self-Dispersion Monodisperse Silica-Based Functional Nanoparticles for Enhanced Oil Recovery (EOR) in Low-Permeability Reservoirs

A controllable particle size mono-dispersing nanofluid system has been developed to address the challenges of low porosity and low-permeability in low to ultra-low-permeability reservoirs. This system combines high dispersion stability with enhanced oil recovery performance, and its effectiveness in improving recovery rates in low-permeability reservoirs, where conventional chemical flooding is ineffective, has been well demonstrated. Using the in situ method to prepare monodispersed nano-silica particles, the effects of the water concentration, ammonia concentration, and silica precursor concentration on the morphology, particle size, and formation time of the silica spherical particles were analyzed. Building on this foundation, a partially hydrophobic modified nano-silica oil displacement fluid was synthesized in situ. The system’s dispersion stability, ability to reduce oil-water interfacial tension, and capacity to alter rock wettability were evaluated. Core physical models were used to evaluate the oil displacement efficiency and the permeability applicability limits of the self-dispersing nano-silica oil displacement system. The experiments confirmed that the particle size distribution of the self-dispersing nano-silica oil displacement system can be controlled within a range of 10 nm to 300 nm. The nanofluids exhibited excellent stability, effectively altering the rock wettability from oil-wet to water-wet and reducing the oil-water interfacial tension to approximately 10−1 mN/m. The nano-displacement system increased the recovery rate of the low permeability reservoirs by more than 17%. The in situ modification method used to prepare these self-dispersing nanoparticles provides valuable insights for synergistic enhancement of recovery when combined with other systems, such as surfactants and CO2. This approach also opens up new possibilities and drives further development in the field of nano-enhanced oil recovery chemistry.

Hyperbranched Organosilicon Surfactants as Emulsifiers for the Emulsion Polymerization of Methyl Methacrylate

This report is devoted to the investigation of the emulsion polymerization of methyl methacrylate in the presence of PEGylated hyperbranched polymethylethoxysiloxane as an emulsifier. It is shown that its use in the amount of 1–5 wt % affords stable 25–50% poly(methyl methacrylate) dispersions with the controlled particle sizes from 300 to 800 nm and a narrow particle size distribution.

2-Axis controlled spray pyrolysis deposition device for Dye-sensitized Solar Cell (DSSC)

Dye-sensitized solar cells (DSSCs) are a promising alternative to traditional silicon-based photovoltaic systems due to their efficient light-to-electricity conversion. A critical component of DSSCs is titanium dioxide (TiO2), responsible for converting light into electrical energy. Spray pyrolysis was one of the methods for fabricating TiO2 thin films. However, there are several drawbacks, such as challenges in particle size control, maintaining homogeneity of the thin film, and scalability issues during the deposition process. Modifications to the manufacturing process are necessary to achieve optimal performance in DSSCs, particularly with the thickness of the cell. This work focuses on the 2-axis spray pyrolysis process, a cost-effective way to create thin and thick films. In particular, it focuses on TiO2 thin films utilized as working electrodes in DSSC applications. The method was performed at different motor speeds, namely MS80, MS100, and MS120. The X-ray diffraction (XRD) spectrum showed that the dominance of the anatase phase appeared in an MS100. The UV-Vis results depict that the band gap value is 3.02 eV. The surface profiler analysis indicates that sample MS100 has an optimal thickness of 15.17 µm. The DSSC achieved 9.4% efficiency with sample MS100. This finding demonstrates that using 2-axis controlled spray pyrolysis deposition improves DSSC performance with an optimal motor speed.

Synthesis of α-LiAlO<sub>2</sub> powders of controlled particle size composition for a matrix electrolyte based on carbonate melts

Three methods of synthesis α-LiAlO2 powders for the preparation of a matrix electrolyte for a molten carbonate fuel cell have been considered. The submicron fraction with a specific surface area of 79 m2/g was obtained from an aqueous solution by spray pyrolysis and the large rod-shaped fractions with particles up to 19 μm in length were obtained by synthesis in halide melt and in aqueous solution. Tape casted ceramic matrices were tested in the single fuel cell with 53Li2CO3–47Na2CO3 melt as an electrolyte. The matrices have demonstrated good gas tightness; nitrogen inleakage in anode space did not exceed 0.6 % during 1100 h lifetime test, which included 15 thermal cycles with cooling the cell below melting point of the electrolyte.

High-efficiency synthesis of colloidal silica via suppression of foam layer

As an important fundamental material, colloidal silica is widely used in many fields. Hydrolysis of elemental silicon is an important method for the preparation of colloidal silica. This method has been widely studied because of its simple process, low cost, easy control of colloidal particle size and good stability. However, this method has the problem of low reaction conversion rate (RCR). This paper proposed an efficient method to increase RCR of colloidal silica by inhibiting the formation of a foam layer. After the size of the silicon powder particle, reaction time, and the defoamer types were optimized, the defoamer of hydrophobic fumed silica could effectively inhibit the increase of foam layer and improve the yield of colloidal silica, the RCR was significantly increased from 54.8 % to 85 % within 4 h. This research provides an innovative strategy for the efficient chemical synthesis of colloidal silica.

Structural and Optical Properties of Nickel-Doped Zinc Sulfide.

In this study, undoped and Ni-doped ZnS nanoparticles were fabricated using a hydrothermal method to explore their structural, optical, and surface properties. X-ray diffraction (XRD) analysis confirmed the cubic crystal structure of ZnS, with the successful incorporation of Ni ions at various doping levels (2%, 4%, 6%, and 8%) without disrupting the overall lattice configuration. The average particle size for undoped ZnS was found to be 5.27 nm, while the Ni-doped samples exhibited sizes ranging from 5.45 nm to 5.83 nm, with the largest size observed at 6% Ni doping before a reduction at higher concentrations. Fourier-transform infrared (FTIR) spectroscopy identified characteristic Zn-S vibrational bands, with shifts indicating successful Ni incorporation into the ZnS lattice. UV-visible spectroscopy revealed a decrease in the optical band gap from 3.72 eV for undoped ZnS to 3.54 eV for 6% Ni-doped ZnS, demonstrating tunable optical properties due to Ni doping, which could enhance photocatalytic performance under visible light. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) analyses confirmed the uniform distribution of Ni within the ZnS matrix, while X-ray photoelectron spectroscopy (XPS) provided further confirmation of the chemical states of the elements. Ni doping of ZnS nanoparticles alters the surface area and pore structure, optimizing the material's textural properties for enhanced performance. These findings suggest that Ni-doped ZnS nanoparticles offer promising potential for applications in photocatalysis, optoelectronics, and other fields requiring specific band gap tuning and particle size control.

1,2-bis(triethoxysilyl)methane (BTESM)-derived organic–inorganic membranes with controlled sol particle size: Preparation and pervaporation dehydration performance of isopropanol aqueous solutions

1,2-bis(triethoxysilyl)methane (BTESM) is a bridged-type organoalkoxysilane, which was utilized for organic–inorganic membranes preparation via a sol–gel method to achieve high permselectivity, thus are promising for dehydration and purification of organic solvents. However, the particle size of the derived sol is crucial for membrane preparation during sol–gel processing, significantly influencing the membrane’s performance. Herein, we reported a novel strategy of controlling the sol particle size by adjusting the pH during the preparation process. BTESM-derived membranes were prepared by BTESM-H+ sol and BTESM-swing sol, which were subsequently employed for the dehydration of isopropanol (IPA) through pervaporation (PV). Compared with the BTESM-H+ sol, the particle size of the BTESM-swing sol prepared by the pH-swing method was increased from 1.3 nm to 32.7 nm. The larger particle size could hinder the permeation into the intermediate layer. Meanwhile, the dense arrangement of silica particles could efficiently retain IPA molecules, thereby substantially enhancing the rejection rate of IPA. The average particle size of the BTESM-swing sol was 18.7 nm at an acid-base ratio of 1.2 and acid-silicon ratio of 0.55, resulting a permeate flux of 1.04 kg·m−2·h−1 and separation factor of 521, while IPA rejection rate was 97.84 %. This work has shown that adjusting the pH during the process is a useful strategy of controlling the sol size for the preparation of organic–inorganic membranes. Hence, the control of sol particle size to achieve a high-performing membrane layer offers a novel approach to producing diverse membrane materials.

Novel Synthesis Route of Plasmonic CuS Quantum Dots as Efficient Co-Catalysts to TiO2/Ti for Light-Assisted Water Splitting.

Self-doped CuS nanoparticles (NPs) were successfully synthesized via microwave-assisted polyol process to act as co-catalysts to TiO2 nanofiber (NF)-based photoanodes to achieve higher photocurrents on visible light-assisted water electrolysis. The strategy adopted to perform the copper cation sulfidation in polyol allowed us to overcome the challenges associated with the copper cation reactivity and particle size control. The impregnation of the CuS NPs on TiO2 NFs synthesized via hydrothermal corrosion of a metallic Ti support resulted in composites with increased visible and near-infrared light absorption compared to the pristine support. This allows an improved overall efficiency of water oxidation (and consequently hydrogen generation at the Pt counter electrode) in passive electrolyte (pH = 7) even at 0 V bias. These low-cost and easy-to-achieve composite materials represent a promising alternative to those involving highly toxic co-catalysts.

Enhanced Lithium Extraction from Brines: Prelithiation Effect of FePO4 with Size and Morphology Control.

Extracting lithium resources from seawater and brine can promote the development of the new energy materials industry. The electrochemical method is green and efficient. Iron phosphate (FePO4) crystal, with its 1D ion channel, holds significant potential as a primary lithium extraction electrode material. Li+ encounters a substantial concentration disadvantage in brines, and the co-intercalation of Na+ diminishes Li+ selectivity. To address this issue, this work enhances the energy barrier for Na+ insertion through prelithiation strategies applied to the 1D channels of FePO4 crystal, thereby improving Li+ selectivity, and further investigating the prelithiation effect with particle size and morphology control. The results indicate that the Li(4C-40%)FePO4// Activated carbon(AC) system enhances selectivity of lithium. The Li(4C-40%)FePO4 with size diameter of 2500nm demonstrates an energy consumption of 0.79Whmol-1 and a purity of 97.94% for lithium extraction at a unit lithium extraction of 5.93mmolg-1 in simulated brine. Li(4C-40%)FePO4-nanoplates demonstrate the most optimal lithium extraction performance among the three morphologies due to their lamellar structure's short ion diffusion path in the [010] channel, favoring Li+ diffusion. The diffusion energy barriers of Li+ and Na+ are calculated using Density Functional Theory (DFT) before and after prelithiation, showing good agreement with experimental results.

Controlling particle size of levan in powder form with different technologies

Levan is a fructose polysaccharide with multiple applications in different fields, but its obtaining in powdered form with a narrow particle size distribution is a complicated task. Two techniques, electrospraying and supercritical antisolvent (SAS) precipitation, were used to process levan that was first obtained enzymatically. The SAS process was able to micronize the polymer (at experimental conditions far above the mixture critical point of the solvent-antisolvent system) to obtain spherical particles between 0.30 and 0.50 μm with a proper particle size distribution. In this case, the Peng-Robinson equation of state was used to theoretically determine the mixture critical point. Bigger and elongated particles were obtained with electrospraying (0.60 μm). According to solution properties, mainly rheology, solubility and conductivity, the best solvent for levan electrospraying, in order to avoid problems of solvent evaporation and jet formation, was a mixture of water and ethanol with a polymer concentration of 50 mg·cm−3. Indeed, that solution has a viscous behavior (according to the oscillatory analysis), a low degree of pseudo-plasticity (based on the shear flow analysis), and the highest value of conductivity. Therefore, the particle size distribution of levan in powdered form can be tuned depending on the technique used.

Preparation and photothermal properties of latent functional thermal fluid based on size-controllable phase change nanocapsules

To improve the solar heat utilization efficiency of working fluid in direct solar collector, a novel latent functional thermal fluid (LFTF) based on self-designed 1-octadecanol@silica phase change nanocapsules (NEPCMs) with excellent heat storage capacity and photothermal conversion efficiency were prepared. The NEPCMs prepared by sol–gel method were dispersed in water containing multi-walled carbon nanoparticles to prepare the LFTF. The prepared NEPCMs have high encapsulation efficiency (85.12 %) and melting phase change enthalpy (235.1 J/g), controllable particle size (27.13–167.30 nm), excellent thermal stability and cycle stability. The LFTF containing 10 wt% NEPCMs was considered the optimal choice for its excellent dispersion stability (zeta potential 35.63 mV), thermal storage capacity (peak specific heat capacity 5.11 J·g−1·K−1) and superior photothermal conversion efficiency (up to 98 %), which is roughly 3.29 times that of water. These results offer valuable insights for the future development of LFTF in the field of solar thermal applications.

Comprehensive Utilization of Formation Water Scale to Prepare Controllable Size CaCO3 Nanoparticles: A New Method to Improve Oil Recovery.

Formation water scale blocks pipelines and results in oil/gas production decreasing and energy consumption increasing. Many methods have been developed to inhibit scale formation. However, these previous methods are limited by their complications and low efficiency. A new method is proposed in this paper that uses the scale in formation water as a nanomaterial to improve oil recovery via controlling particle size. A series of ligands were synthesized and characterized. Micrometer-CaCO3 was formed and accumulated to form scale of a large size under uncontrolled conditions. The tetradentate ligands (L4) exhibited an excellent capturing yield of Ca2+ (87%). The particle size was very small, but they accumulated to form large particles (approximately 1300 nm) in the presence of Na2CO3. The size of the CaCO3 could be further controlled by poly(aspartic acid) to form sizes of about 700 nm. The flooding test showed that this material effectively improved oil recovery from 55.2% without nano CaCO3 to 61.5% with nano CaCO3. This paves a new pathway for the utilization of Ca2+ in formation water.

Sustainable synthesis of iron oxide nanopigments: Enhancing pigment quality through combined air oxidation and cavitation techniques

This study investigates the synthesis and characterization of iron oxide pigments through various methods, including air oxidation, co-precipitation, and hydrodynamic cavitation. The infrared (IR) spectral analysis revealed key functional groups and metal-oxide bonds indicative of goethite, with bands associated with O–H stretching and Fe–O vibrations. The study also explores how different conditions, such as temperature, pH, and reactant ratios, affect the color, yield, and particle size of the pigments produced. Through batch and continuous synthesis processes, it was found that cavitation offers a more controlled particle size distribution compared to other methods. The experiments highlight the influence of parameters like temperature, pH, and NaOH concentration on the final pigment properties, with optimized conditions yielding high-quality pigments. The comparison of synthetic methods demonstrates the trade-offs in terms of reaction complexity, particle size control, and yield, emphasizing the potential of hydrodynamic cavitation for efficient and scalable pigment production. The study concludes by summarizing the versatile reactions of FeSO4 and NaOH in producing various iron oxide and oxyhydroxide materials, which are valuable in industrial and environmental applications.

Highly efficient nucleic acid encapsulation method for targeted gene therapy using antibody conjugation system

Gene therapy has surfaced as a promising avenue for treating cancers, offering the advantage of deliberate adjustment of targeted genes. Nonetheless, the swift degradation of nucleic acids in the bloodstream necessitates an effective and secure delivery system. The widespread utilization of poly lactic-co-glycolic acid (PLGA) nanoparticles as drug delivery systems has highlighted challenges in controlling particle size and release properties. Moreover, the encapsulation of nucleic acids exacerbates these difficulties due to the negatively charged surface of PLGA nanoparticles. In this study, we aimed to improve the encapsulation efficiency of nucleic acids by employing negatively charged microbeads and optimizing the timing of the specific formulation steps. Furthermore, by conjugating PSMA-617, a ligand for the prostate-specific membrane antigen (PSMA), with PLGA nanoparticles, we assessed the antitumor effects and the efficacy of a nucleic acid delivery system on prostate cancer model. The employed technique within the nucleic acid encapsulation system represents a novel approach that could be adapted to encapsulate various kinds of nucleic acids. Moreover, it enables the attachment of targeting moieties to different cell membrane proteins, thereby unveiling new prospects for precise therapeutics in cancer therapy.

Thermally synthesized hematite (α-Fe2O3) nanoparticles as efficient photocatalyst for visible light dye degradation.

In recent years, water pollution has become a pressing global issue because of the continuous release of organic dyes from various industries. Therefore, finding an easy way to remove these harmful dyes from water has drawn the attention of researchers. This study investigates the removal of toxic Rose Bengal (RB) dye using hematite nanoparticles as a visible light photocatalyst without any additive. It is observed that by controlling particle size, quantity of the nanoparticles and reaction temperature, the dye degradation can be improved up to 95.33% with a half-life of 26 min. To understand photodegradation kinetic behavior, the Langmuir-Hinshelwood kinetic equation can be employed. The scavenger test indicated that the OH* radicals majorly led to the photodegradation process. The reaction rate values strongly depended on the size, quantity of the nanoparticles and reaction temperature. Controlling the optimizing condition, faster reaction rate (k = 0.027 min-1) can be achieved as compared to earlier reports. It is also noted that the change in the degradation efficiency of the reused catalyst is negligible when compared to the fresh one. Here, the dye degradation mechanism is discussed. Overall, this study reveals that hematite nanoparticles can be used as efficient photocatalyst for dye degradation applications by optimizing the controlling factors. These observations provide novel perspectives on the development of effective and sustainable photocatalytic technologies for pollution control and water treatment applications.

Improving the re-use potential of reactive waste rock using sieving: a laboratory geochemical study

Stockpiles containing sulfide minerals are subject to oxidation reactions when exposed to atmospheric conditions, which can result in the formation of acid mine drainage (AMD). Reactive waste rock has limited re-use potential due to the contamination risk associated with the generated drainage water. The re-use of reactive waste rock could lead to a significant reduction in the volume of waste rock as it mitigates the environmental impact of mine waste deposition. Acid mine drainage generation rate depends on sulfide weathering kinetics which are controlled by many parameters such as the mineralogy and the particle size. Fine fractions of waste rock have higher specific surface areas and degree of liberation of sulfides, resulting in greater reactivity than the coarse fractions. The objective of this research was therefore to evaluate the potential of re-use by controlling particle size using the sieving method. Two different potentially acid-generating waste rocks were divided into six fractions and subjected to both static and kinetic tests. Prediction of the geochemical behavior using static test did not consider the liberation of the minerals, and the long-term prediction was therefore overestimated. Results of the kinetic columns showed there was less oxidation of the sulfide minerals in the coarse fractions than in the fine fractions. Additionally, the distribution of sulfidic minerals and neutralizing minerals with particle size is influencing the potential of the re-use of the reactive waste rock.

Silica particle size and polydispersity control from fundamental practical aspects of the Stöber method

Silica-based nanoparticles have been continuously investigated for their physical and chemical properties, which have made them adaptable for a wide range of scientific purposes, from adsorption in an aqueous medium to target-specific drug delivery in biological fluids. The achievement of these properties is, in general, possible by controlling the synthesis of the nanomaterial, and the Stöber method is one of the most commonly employed approaches for silica-based nanoparticles. In this study, experiments were carried out to investigate several parameters of the Stöber method for controlling the diameter and size dispersion of silica nanoparticles. The results of these experiments were supported by and contrasted with the theoretical aspects of silica particle nucleation and growth models. In this scenery, practical aspects of the Stöber Method such as the effects of variations in catalyst concentration, colloidal stability and drying approach on particle size and polydispersity were examined in detail for providing an organized basis of experimental and theoretical data about it for who aims at work with silica nanoparticle synthesis through the Stöber Method.

Molecularly Imprinted Microspheres in Active Compound Separation from Natural Product.

Molecularly Imprinted Microspheres (MIMs) or Microsphere Molecularly Imprinted Polymers represent an innovative design for the selective extraction of active compounds from natural products, showcasing effectiveness and cost-efficiency. MIMs, crosslinked polymers with specific binding sites for template molecules, overcome irregularities observed in traditional Molecularly Imprinted Polymers (MIPs). Their adaptability to the shape and size of target molecules allows for the capture of compounds from complex mixtures. This review article delves into exploring the potential practical applications of MIMs, particularly in the extraction of active compounds from natural products. Additionally, it provides insights into the broader development of MIM technology for the purification of active compounds. The synthesis of MIMs encompasses various methods, including precipitation polymerization, suspension polymerization, Pickering emulsion polymerization, and Controlled/Living Radical Precipitation Polymerization. These methods enable the formation of MIPs with controlled particle sizes suitable for diverse analytical applications. Control over the template-to-monomer ratio, solvent type, reaction temperature, and polymerization time is crucial to ensure the successful synthesis of MIPs effective in isolating active compounds from natural products. MIMs have been utilized to isolate various active compounds from natural products, such as aristolochic acids from Aristolochia manshuriensis and flavonoids from Rhododendron species, among others. Based on the review, suspension polymerization deposition, which is one of the techniques used in creating MIPs, can be classified under the MIM method. This is due to its ability to produce polymers that are more homogeneous and exhibit better selectivity compared to traditional MIP techniques. Additionally, this method can achieve recovery rates ranging from 94.91% to 113.53% and purities between 86.3% and 122%. The suspension polymerization process is relatively straightforward, allowing for the effective control of viscosity and temperature. Moreover, it is cost-effective as it utilizes water as the solvent.