X-ray Fluorescence Research Articles

Amorphous silica production from Colombian rice husk: demonstration in scaled-up process Products

Introduction: the agroindustry generates significant waste, posing environmental, health, and economic challenges. Among these, rice husk, a byproduct of the food industry, stands out due to its potential as a source of silicon. Due to its silicon content, rice husk offers a unique opportunity for sustainable energy production and the extraction of high-value products, such as amorphous silicon dioxide (SiO2). However, optimizing processes for its efficient conversion remains a challenge.Objective: the aim of this study was to optimize the nitric acid concentration for the pretreatment of Colombian rice husk in order to produce high-purity amorphous SiO2 and demonstrate the feasibility of scaling up the process.Methods: a two-stage process was developed, which involved treating rice husk with nitric acid, followed by calcination at 620 °C. The nitric acid concentration was optimized to achieve the highest SiO2 purity. Material characterization was performed using thermogravimetric analysis (TGA), X-ray diffraction (XRD), X-ray fluorescence (XRF), and nitrogen adsorption-desorption. To assess the scalability of the process, the treatment was replicated on a larger scale using the optimized acid concentration.Results: the optimized process using a nitric acid concentration of 0.2 M yielded amorphous SiO2 with a purity of 94.9% and a surface area of 298 m²/g. When scaled up, the process achieved SiO2 with a purity of 95.5%, confirming the feasibility of the methodology for industrial applications. Conclusions: the treatment of rice husk with nitric acid followed by calcination proves to be an effective and scalable approach for producing high-purity amorphous SiO2. This process not only holds potential for industrial applications but also provides a sustainable solution for valorizing agroindustrial waste, contributing to the circular economy.

Layers and Layers: Analysis and Treatment of Egyptian Cartonnage at the Penn Museum

ABSTRACT Egyptian cartonnage is a complex material, creating challenges around analysis, treatment, display, and storage. It consists of layers of linen and/or papyrus, followed by a ground layer, then paint, each with its own conservation challenges. This paper provides information on a little published material through presentation of analysis and treatment methods. A group of cartonnage objects were examined and treated at the Penn Museum. This paper will explain the analytical methods employed to identify materials and examine observed deterioration. These objects would have originally covered the body of a deceased individual. All the pieces presented here have been separated from the individuals they belonged to, which has caused some of the observed deterioration, as well as subsequent improper storage. Preferential deterioration of certain paints has also been observed. The prevalence of each condition issue and how it may relate to manufacture and treatment/handling history will be discussed. Preliminary pigment characterization was conducted using portable X-ray fluorescence, multimodal photography, digital microscopy, and reflectance transformation imaging. This included the possible discovery of tin leaf on a small selection of masks, a material which has not previously been identified on objects from ancient Egypt.

Raman spectroscopy combined with active hyperspectral sensing for classification of waste plastics containing brominated flame retardants: A sensor fusion approach.

Discrimination of waste plastics according to brominated flame retardant (BFR) concentration is essential to ensure quality and safety in recycling. We present a sensor fusion approach to classify BFR-containing plastic waste by combining Raman and near-infrared (NIR) spectroscopies. We analysed 210 waste plastic samples sourced from waste electronics and electrical equipment stream and 25 laboratory-made plastics. The Raman spectra were acquired in the range 27-2481 cm-1 using a time-gated Raman and the NIR spectra in the range 4000-5260 cm-1 using a novel active hyperspectral sensor. Total elemental bromine concentrations were determined with X-ray fluorescence spectroscopy and used as reference for training extremely randomized trees classifiers for high- and low-bromine plastics with different thresholds of segmentation. The classifier models were built using Raman and NIR spectral data after reducing dimensions with principal component analysis, both separately and by fusing the data. We achieved over 80% balanced classification accuracies using all models, with significant improvements by data fusion.

The Influence of Temperature and Stoichiometry on the Optical Properties of CdSe Nanoplatelets

Colloidal quasi-two-dimensional cadmium chalcogenide nanoplatelets have attracted considerable interest due to their narrow excitonic emission and absorption bands, making them promising candidates for advanced optical applications. In this study, the synthesis of quasi-two-dimensional CdSe NPLs with a thickness of 3.5 monolayers was investigated to understand the effects of synthesis temperature on their stoichiometry, morphology, and optical properties. The NPLs were synthesized using a colloidal method with temperatures ranging from 170 °C to 210 °C and optimized precursor ratios. Total reflection X-ray fluorescence (TXRF) analysis was employed to determine stoichiometry, while high-resolution transmission electron microscopy (HRTEM) and UV-Vis spectroscopy and photoluminescence spectroscopy were used to analyze the structural and optical characteristics. The results showed a strong correlation between increasing synthesis temperature and the enlargement of nanoscroll diameters, indicating dynamic growth. The best results in terms of uniformity, stoichiometry, and optical properties were achieved at a growth temperature of 200 °C. At this temperature, no additional optical bands associated with secondary populations or hetero-confinement were observed, indicating the high purity of the sample. Samples synthesized at lower temperatures exhibited deviations in stoichiometry and optical performance, suggesting the presence of residual organic compounds.

Characterization of Palm Kernel Shell Ash Nanoparticles as Coating Material for High Temperature Applications

The kernel shell of oil palm (Elaesis guineensis) was milled, calcinated and synthesized into nanoparticles (np) with a view to analyzing and ascertaining its high temperature strength. The synthesized particles were characterized to reveal their elemental composition and temperature of maximal decomposition/destruction, with the solgel method employed in the nanoparticle synthesis. The morphology of the Palm Kernel Shell Ash nanoparticles (PKSAnp) viewed from Transmission Electron Microscope (TEM) revealed that the nanoparticles were solid in nature but vary in sizes with some spherical particles visible, and an average particle size found to be 39.17nm. The Electron Dispersion Spectroscope (EDS) result shows that only elements such as C, O, Si, Al, Ca, and K are present in the PKSAnp, with silicon (Si) found to be dominant. Oxides of Silicon and Aluminum (SiO2 and Al2O3) were identified as the key chemical compounds in PKSAnp from X-Ray Fluorescence (XRF) investigation whereas K2O, CaO and Na2O were among the other oxides present in traces. The Thermogravimetric analysis (TGA) curve shows a lower proportion of breakdown and a residual weight stability at temperatures above 1000oC, coinciding with the silica content in PKSAnp. This is comparable and consistent with known high temperature coating materials in previous literature.

Cellular targets of cytotoxic copper phenanthroline complexes: a multimodal imaging quantitative approach in single PC3 cells.

Metal complexes are emerging as promising alternatives to traditional platinum-based cancer treatments, offering reduced side effects. However, understanding their cellular uptake and distribution and quantify their presence at the single cell level remains challenging. Advanced imaging techniques, including transmission electron microscopy (TEM), synchrotron radiation X-ray fluorescence (SR-XRF) and energetic ion beam-based nuclear microscopy (STIM, scanning transmission ion microscopy; PIXE, particle-induced X-ray emission; EBS, elastic backscattering spectrometry), allow detailed high-resolution visualization of structure and morphology, high sensitivity for elemental detection with quantification within single cells, and the construction of three-dimensional (3D) models of metal distribution, positioning them as powerful tools for assessing the cellular uptake and compartmentalisation of complexes. Three Cu(II) complexes [Cu(phen)2(H2O)](NO3)2 (1), [Cu(Me2phen)2(NO3)]NO3 (2) and [Cu(amphen)2(H2O)](NO3)2 (3), (phen = 1,10-phenanthroline, Me2phen = 4,7-dimethyl-1,10-phen, amphen = 5-amino-phen) were investigated for Cu uptake and distribution in PC3 prostate cancer cells. All complexes show significant Cu-uptake regardless of media concentration. Cu-concentrations in cytoplasm and nucleus are similar between treatments. Complexes 1 and 3 concentrate Cu in the nuclear region and show a vesicle-like pattern around the nucleus, while 2 shows a dispersed cytoplasmic pattern with large vesicles. The 3D models confirm that Cu is not retained at the plasma membrane, with complex 1 targeting the nucleus and 2 remaining in the cytoplasm. These results highlight the importance of quantifying metal distribution and correlating it with structural changes to understand the relevance of the ligand in the mechanisms of cellular uptake and targeting, crucial for the development of effective metal-based cancer therapies.

Characteristics of foundries and alloy composition of modern and contemporary Korean artistic bronze

This study investigated the changes in foundries and production techniques of modern and contemporary Korean artistic bronze constructions from the 1910s to the 2000s. To determine the characteristics of foundries and changes in alloy composition based on era, interviews with key sculptors and foundry technicians, analysis of archival materials related to casting, and nondestructive X-ray fluorescence analysis of 92 bronze sculptures by Manlin Choi, were conducted. This study found that foundries for artistic bronze underwent technical and organizational changes from the 1910s to the 2000s. Modern casting techniques and foreign technologies have been introduced since the late 1960s that have resulted in various production methods. The portable X-ray fluorescence analysis of Manlin Choi’s 92 bronze sculptures revealed distinct differences in alloy composition depending on the foundry, findings that have also been supported by records (contracts, receipts, payment confirmations). This study systematically organizes the changes in foundries and production techniques of modern and contemporary Korean artistic bronze, identifying correlations between alloy composition and foundries, and is expected to provide important data for the future conservation and scientific authentication of artistic bronze.

New Copper(I) oxide biocatalyst based on functionalized olive stone for the synthesis of 1,4-disubstituted-1,2,3-triazoles under very mild conditions

An efficient methodology for coating silanized olive stone with copper(I) oxide has been described and fully characterized using various techniques, including X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR-ATR), X-ray fluorescence (XRF), electronic microscopy, thermogravimetric analysis (TGA), moisture content, electrophoretic mobility and particle size distribution. The applicability of this new biocatalyst in the 1,3-dipolar cycloaddition click reaction between alkynes and azides has been demonstrated leading to the obtention of a great variety of 1,4-disubstituted-1,2,3-triazoles with good to excellent conversions. The new biocatalyst showed promising features in terms of recyclability and industrial or biomedical application. It could be recycled up to five times with minimal loss of catalytic activity when synthezing compound 3a-3n. Additionally, it was effective in the multi-gram scale synthesis of compounds 3b and 3e, which were tested for the first time in cells, specifically on the human fibroblast-derived M1 cell line, demonstrating that these compounds are non-cytotoxic and thus suitable for potential uses in biomedicine.

Electrochemical Degradation of Methylene Blue using Aluminum Doped Copper Oxide Electrode: Modeling and Optimization

An electrochemical oxidation process with an aluminum-doped copper oxide (Al@CuO) anode was modeled and optimized for the degradation of methylene blue (MB). The Al@CuO anode material was prepared by the thermal decomposition method. X-ray fluorescence (XRF) analysis confirmed the successful deposition of CuO on the aluminum substrate. The influence of current density, electrolysis time, and MB concentration on the performance of the electrochemical degradation of MB was modeled using Box-Behnken design (BBD). The accuracy of the proposed quadratic model by BBD was confirmed with a p-value < 0.0001 and adj-R2 > 0.9. The optimum MB degradation efficiency of 53.23 % was obtained at 80 mg MB concentration, 40 min electrolysis time, and 3.75 V applied current. The kinetics on the MB electrochemical degradation process using Al@CuO followed pseudo first-order kinetics model. These studies revealed that the Al@CuO anode electrode is not a promising anode for the electrochemical degradation of methylene blue.

Palynofacies as sea-level-sensitive proxy in Early Cretaceous marine mudstones – A critical evaluation

Stratigraphic distribution patterns of particulate organic matter (POM) have been widely used for facies recognition and paleoenvironmental interpretation as well as to decipher proximal to distal trends within fine-grained sediments. The Lower Cretaceous mudstone-dominated succession in the eastern Lower Saxony Basin (LSB) offers an excellent opportunity to critically evaluate such palynofacies parameters, commonly used to identify transgressive-regressive (T-R) cycles in marine sediments. For the seemingly monotonous succession, a robust sequence stratigraphic framework has been previously established by integrating high-resolution elemental intensity data from X-Ray Fluorescence (XRF) core scanning and biostratigraphy from four drill cores. In this study, the composition and distribution of the POM has been assessed by analysis of 220 strew mounts using transmitted-light microscopy. Overall, the POM composition indicates deposition in a mud-dominated proximal to distal shelf setting. The ratio of opaque versus translucent phytoclasts (OP/TR ratio) shows a distinct long-term increase from the Berriasian onwards with maximum values during the early Hauterivian, followed by a subsequent decrease in OP/TR ratio. This trend broadly reflects the overall T-R evolution of the succession interpreted from Si/Al changes. This also applies to the size and sorting of opaque phytoclasts, with the greatest amplitude changes in opaque particle size parameters being observed in the more proximal deposits of the studied succession. On the other hand, the ratio of terrestrial versus marine palynomorphs (T/M ratio), often applied as indicator of proximal to distal trends and distances from the coastline, shows no correlation with the T-R cycles. Systematic long- and short-term trends visible in T/M ratio correspond to variations in the XRF-derived Ca/Ti stratigraphic trend, which is interpreted to reflect variations in carbonate content. This may indicate that the T/M ratio in the LSB is largely controlled by variations in marine palynomorph flux, probably related to productivity changes of the organic-walled microplankton.

Microscale chemical imaging to characterize and quantify corrosion processes at the metal-electrolyte interface

We introduce an experimental setup to chemically image corrosion processes at metal-electrolyte interfaces under stagnant, confined conditions—relevant in a wide range of situations. The setup is based on a glass capillary, in which precipitation of corrosion products in the interfacial aqueous phase can be monitored over time with optical microscopy, and chemically and structurally characterized with microscopic synchrotron-based techniques (X-ray fluorescence, X-ray diffraction, and X-ray absorption spectroscopy). Moreover, quantification of precipitates through X-ray transmission measurements provides in-situ corrosion rates. We illustrate this setup for iron corrosion in a pH 8 electrolyte, revealing the critical role of O2 and iron diffusion in governing the precipitation of ferrihydrite and its transformation to goethite. Corrosion and coupled reactive transport processes can thus be monitored and fundamentally investigated at the metal-electrolyte interface, with micrometer-scale resolution. This capillary setup has potential applications for in-situ corrosion studies of various metals and environments.

Sulfur Diffusion Studies Imitating Recycled Ground-Rubber-Containing Compounds

In-rubber properties of vulcanizates deteriorate in the presence of incorporated recycled ground rubber (GR). This behavior is partly explained by a possible diffusion of sulfur from the rubber matrix into the GR. Therefore, the sulfur concentration and, thus, the crosslink density in the matrix are reduced. This phenomenon was further investigated in this research work using two spatially resolved methods that supplement each other: the diffusion of soluble sulfur in GR-containing compounds was locally investigated via Micro X-Ray Fluorescence analysis. Viscoelastic properties were also determined spatially by the Micro Dynamic-Mechanical Indentation method. Combining the results of both methods, local concentrations of sulfur were related to local viscoelastic properties, revealing great differences in crosslink density at the interface between the GR and matrix material. In this way, it is shown that sulfur is capable of diffusing several mm, which locally doubles its concentration with respect to the sulfur content of the compound formulation. This, in turn, negatively impacts the homogeneity of crosslink density in both the matrix and GR, revealing a local increase in the elastic stiffness of 100 %. In addition, it was found that the vulcanization characteristics of the used polymers determine the amount of sulfur diffusion and, thus, the change in viscoelastic properties.

What jewelry did people wear in the Middle Byzantine period (10th-12th C. CE) in the Peloponnese? A technological and analytical case study

The present paper presents the preliminary results of the archaeometric analysis of a Middle Byzantine jewelry assemblage made of non-precious metals from the ancient site of Pallantion, near Tripoli (Peloponnese, Greece). The assemblage under examination consists of 26 artifacts, including earrings, finger rings and buckles. Macroscopic observations and optical microscopy were used to examine the manufacturing technology of the artifacts, with a particular focus on the manufacturing technology of wires. The proposed methodology combined a Handheld X-ray Fluorescence Spectrometer (HH-XRF) and a Micro X-ray Fluorescence Spectrometer (μ-XRF) to group the alloys used in the manufacture of the jewelry, despite the presence of corrosion. This methodology indicated that the majority of the artifacts was made of bronze, leaded or not, and gunmetal. Moreover, a quantification criterion was used to determine the state of preservation of the surface of the jewelry. Overall, the present study highlights the manufacturing technology of jewelry of the Middle Byzantine period and the tendency to imitate silver jewelry with lower-cost materials.

AUGITE-BASED CERAMICS OBTAINED BY SOLID-STATE SINTERING OF LOESS

Loess from the Danubian Plain (Bulgaria) was used as the raw material for the solid-state synthesis of ceramics.The mineral phase composition of the loess fraction used was determined by powder X-ray phase analysis, and the chemical composition by X-ray fluorescence analysis. The semi-quantitatively determined mineral phases are quartz, plagioclase, K-feldspar, mica, carbonates (calcite and dolomite), chlorite and amphibole. The major oxides of the chemical composition of loess fraction are (in wt. %): SiO2 - 53,61; Al2O3 - 12.57; Fe2O3 - 7.05; P2O5 - 0,23; TiO2 - 1.37; CaO - 19.36; and MgO - 1.48. Experiments were performed with sintering of pure loess without additives, and with addition of MgO and Na2O in order to obtain a composition corresponding to that of the pyroxene augite - (Ca,Na)(Mg,Fe,Al,Ti)(Si,Al)2O6. Ceramics were obtained at three temperatures: 1000, 1100 and 1200°C. The phase composition, spectral characteristics and colour coordinates of the obtained ceramics were determined. The results show that when magnesium and sodium are added to the loess raw material, the ceramics obtained after sintering at 1100 and 1200°C have a predominant content of augite and have a yellow-beige colour.

Some educational uses of EDXRF for technologists in health science

Abstract Physicists teach physics to students of various academic disciplines such as physics, chemistry, health sciences, biology, geology, environmental sciences, etc. Energy dispersive X-ray fluorescence spectroscopy (EDXRF) is a case of application of atomic physics in the real world. Students, through applications of EDXRF, may find out how the basic concepts of atomic physics can be used for elemental analysis of samples of their scientific interest and everyday life. This paper presents some educational implementations of EDXRF and highlights the importance of incorporating this spectroscopic method in undergraduate or postgraduate labs or lectures in the field of health sciences. Five experimental activities, a general one for understanding X-ray spectra and the others for the analysis of substances/materials related to chemistry/toxicology, dentistry, optics, and cosmetics, are presented and discussed.

Heavy metal contamination in soils of industrial estates of Tamil Nadu, India and source identification by magnetic susceptibility.

An increase in erratic industrial activity has been a major contributing factor to the significant contamination in environmental matrices. This study aimed to ascertain the level of heavy metal contamination in soils in major industrial estates of Tamil Nadu as well as the threats to human health and the environment that concomitant with it. This led to the use of the total reflection X-ray fluorescence (TXRF) spectroscopy technique to analyse 31 soil samples. Thus, the mean heavy metal concentrations were found to be in the ascending order: As < Ni < Pb < V < Cu < Zn < Cl < Mn < Sr < Cr < Al < Fe. Pb, Cr, Cu, As, and Zn have been identified as predominantcontaminants in the study area using the conventional pollution indices such as geo-accumulation index (Igeo), contamination factor (CF), and enrichment factor (EF). The magnetic susceptibility measurements indicates that the percentage of frequency dependence of magnetic susceptibility of the studied soil samples varied from 0.88 to 11.15 and that represents the presence of admixture ofsuperparamagnetic (SP) particles in the soil samples. From the results of multivariate statistical analyses, the sources ofidentified heavy metals were classified as anthropogenic sources(Cr, Cu, Pb, As, and Zn),natural sources(V, Mn, Fe, Ni, and Sr ),and intermediate sources (Al and Cl).

Experimental Study of Sugarcane Bagasse Ash as Partial Replacement of Cement Based on SEM and XRF Analysis

This research aims to identify chemical composition and it’s leaching from concrete mixed with sugarcane bagasse ash. By manipulating percent of slump flow at 110±5%, sugarcane bagasse ash was employed as a pozzolanic material to partially replace cement at 0, 10, 20, 30, 40, and 50 percent by weight of binder in concrete. Cube specimens were cast and cured in water for 3, 7, 14 and, 28 days, respectively. The patterns of sugarcane bagasse ash morphology were performed by using Scanning Electron Microscope (SEM) to analyze physicochemical characteristics. Results of tests on the X-ray fluorescence (XRF) analysis from the ash and curing water at various times revealed that SiO2 made up half of the components in sugarcane bagasse ash. Al2O3, CaO, Fe2O3, K2O, P2O5, and MgO were the minor components. The calcium content from the 14-day period at 50% by weight of the sugarcane bagasse ash binder was higher than that of the other elements, according to the results of curing water. According to the results of 28-day water curing, potassium outnumbered all other elements in the replacement of sugarcane bagasse ash in every ratio.

Gabbro of the mantle part of the ophiolite section in the Alapaevsky dunite-harzburgite-gabbro massif (Eastern zone of the Middle Urals)

Research subject. An intrusive body of gabbroids breaking through mantle peridotites (dunites and harzburgites) of the Alapaevsky ophiolite massif (Eastern zone of the Middle Urals). Methods. The contents of petrogenic elements were determined by the X-ray fluorescence method; the contents of rare and scattered elements were studied by the ICP-MS method. The age of gabbroids was determined by 147Sm-143Nd ID-TIMS by isotope dating. Results. The gabbro and their containing ultramafic rocks were established to be of almost the same age of about 580 Ма, which indicates their belonging to a single ophiolite association of the Vendian age. At the same time, the gabbroids of the Alapaevsky massif differ sharply from both isotropic and stratified gabbro of the crustal part of the ophiolite section, fragments of which are observed within the Eastern zone of the Middle Urals, in terms of a significantly reduced content of light REE, rare alkalis, barium, uranium and thorium, as well as the absence of Pb maxima on spider diagrams. Conclusions. The established features in the composition and intrusive occurrence of the gabbro of the Alapaevsky massif among mantle ultramafic rocks indicate that the studied rocks cannot be identified with gabbroids of the crustal part of the ophiolite association. This suggests that this rather large intrusion of gabbro may be analogous to small veins and dikes of gabbroids observed among mantle peridotites in a number of ophiolite massifs, such as Voikar-Synyinsky massif in the Polar Urals and the Samail ophiolite in Oman. The distribution specifics of rare elements on the spider diagrams of the gabbroids of the Alapaevsky massif, i.e., the presence of Sr and Ba maxima and Nd and Th minima, as well as the Harzburgite composition of the mantle restite containing the gabbro body under consideration, indicate that the Vendian ophiolite association of the Eastern zone of the Middle Urals formed in a suprasubduction (pre-arc) environment. A model for the formation of large masses of gabbro in the mantle part of the ophiolite section is proposed.

Iodinated PSMA Ligands as XFI Tracers for Targeted Cell Imaging and Characterization of Nanoparticles

Prostate cancer is the second most commonly diagnosed cancer in men worldwide. Despite this, current diagnostic tools are still not satisfactory, lacking sensitivity for early-stage or single-cell diagnosis. This study describes the development of small-molecule tracers for the well-known tumor marker prostate-specific membrane antigen (PSMA). These tracers contain a urea motif for PSMA-targeting and iodinated aromatic moieties to allow detection via X-ray fluorescence imaging (XFI). Tracers with a triiodobenzoyl moiety allowed the specific targeting and successful imaging of PSMA+ cell lines with XFI. The XFI-measured uptake of 7.88 × 10−18 mol iodine (I) per cell is consistent with the uptake of known PSMA tracers measured by other techniques such as inductively coupled plasma mass spectrometry (ICP-MS). This is the first successful application of XFI to tumor cell targeting with a small-molecule tracer. In addition, iodinated tracers were used for the characterization of quantum dots (QDs) conjugated to PSMA-targeting urea motifs. The resulting targeted QD conjugates were shown to selectively bind PSMA+ cell lines via confocal microscopy. The immobilized iodinated targeting vectors allowed the determination of the tracer/QD ratio via XFI and ICP-MS. This ratio is a key property of targeted particles and difficult to measure by other techniques.

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.