Carbonate minerals occur in great abundance in the Earth’s crust, with calcite (CaCO₃) being the most widespread representative. These minerals are classified into four structural groups: calcite, dolomite, aragonite, and hydroxyl-bearing carbonate groups. Members of the calcite and dolomite groups crystallize in the rhombohedral system, whereas aragonite adopts an orthorhombic structure, and hydroxyl-bearing carbonates are characterized by monoclinic symmetry. Carbonates play a crucial role in the global carbon cycle, serving as major carriers of carbon into the deep Earth. Consequently, the investigation of their physicochemical properties under high-pressure and high-temperature conditions is of considerable scientific interest. Raman spectroscopy is widely employed to obtain thermodynamic properties of these materials because the vibrational properties of a mineral control several of its thermodynamic properties. In this work, five different carbonate minerals from the calcite, dolomite, and aragonite groups were analyzed by pressure and temperature-dependent Raman spectroscopy (calcite, magnesite, dolomite, aragonite, and witherite). Pressures ranged from ambient conditions to approximately 10 GPa, while temperatures ranged from –175 °C to 375 °C, representing a notable extension of the existing literature. From the Raman measurements, values of the isobaric and isothermal Grüneisen parameters were determined, as well as anharmonicity parameters for each of these minerals. The fitting procedures used to obtain these properties included both linear and second-order polynomial m odels for four different Raman modes of the minerals. The results obtained are promising and consistent with previously reported literature data.

Soil microaggregates contain components of organic and inorganic nature. These components interact at the molecular scale forming a hierarchy of aggregates which can build up to reach landscape scales. Such aggregates provide soil with unique properties that depend on a wide range of factors such as the type of minerals and soil organic matter, their location, parent materials, weathering conditions and even human influence. Moreover, molecular interactions are responsible to provide stability to soil which has been discussed as key factor to the decrease of carbon sequestration.

In this regard, computer simulations offer the possibility to access molecular scales, serving as virtual microscopes, to characterize complex systems such as soil at realistic conditions without typical problems such as technical difficulties to measure samples, disturbing or destruction of the samples that ultimately lead to under/over-estimation of measurements. This makes simulation methods ideal to characterize soil samples and provide with molecular signatures that address to particular problems on adsorption of components to soil or even strategies to mitigate climate change.

In this work, we characterized organo-mineral aggregates with different organic composition by using molecular dynamic simulations. We observed that all aggregates exhibit unique responses which result in the development of the electric double layer. We characterize the electric double layer in terms of its charge density profiles and structural properties. By providing a deep understanding at the molecular level of specific organo-mineral aggregates, it could lead to an improvement tunnable to specific soils in several fields such as better design of pesticides, implementation of new strategies for carbon sequestration, efficient removal of pollutants such as toxic heavy metals and organic compounds.

Tectonic activity, as a key driver of long-term climate evolution, influences atmospheric CO₂ concentrations by regulating deep carbon cycling while also shaping the development and distribution of mineral systems in specific geological settings. However, the carbon cycling processes during tectonic transitions and their coupling with mineralization remain poorly constrained. The Bangong-Nujiang Suture Zone (BNSZ), a significant tectonic unit within the Tibetan Plateau, comprehensively records the tectonic evolution from oceanic subduction to post-collision. Its formation coincides with the period of declining atmospheric CO₂ concentrations during the Mesozoic, making it an ideal natural laboratory for investigating the interconnections among tectonics, the carbon cycle, and mineralization systems. This study focuses on mafic rock samples from three key tectonic periods within the BNSZ (subduction, collision, and post-collision), conducting whole-rock geochemical and Pb-Mg-Sr isotopic analyses. The results reveal a fundamental shift in the deep carbon cycling mechanism within the region corresponding to changes in tectonic stages. The primary carrier of carbon migrated transitioned from being fluid-dominated to melt-dominated. This shift not only influenced the efficiency of carbon release but also governed the migration and enrichment of ore-forming elements in associated mineralization systems. During the Early Jurassic subduction stage, carbon was primarily transported as CO₂-rich fluids, resulting in sustained but low-flux degassing. By the Early Cretaceous collision stage, carbon migration shifted to being dominated by carbonate melts, leading to pulsed, high-flux carbon release potentially. In the Late Cretaceous post-collision stage, carbon release became more diffuse, involving enhanced multi-source mixing and crustal assimilation. This mechanistic transition indicates that specific tectonic processes, such as collision, can trigger large-scale, rapid release of deep carbon and ore-forming elements. It provides a novel tectonic-mineralization coupling model for understanding global carbon cycle fluctuations, atmospheric CO₂ evolution, and the formation of large metallogenic provinces during the Mesozoic.

Vitreous ceramics are highly impervious, exhibiting less than 1% water absorption, and are commonly derived from triaxial mixtures of clays, fluxes, and fillers. In this study, nickel laterite mine waste (NiLaMW), a by-product of extraction of nickel ore and the idle silicate deposits in Lanao del Norte, specifically black cinder (a pyroclastic material) and diatomaceous earth, were utilized as alternative raw materials. The NiLaMW was used as a full replacement to clay, while black cinder and diatomaceous earth were utilized as substitutes for feldspar in a typical ternary diagram for ceramic formulation. The thermal properties, morphologies, and mineralogical compositions of these materials were characterized to assess their suitability for vitreous ceramics production. At least three ceramic formulations primarily based on NiLaMW were developed, and their products were formed through the slip casting method. Green wares were sintered at 1200°C. The physico-mechanical properties (linear shrinkage, water absorption, apparent porosity, bulk density, and modulus of rupture “MOR”) of these NiLaMW-based formulations were compared against established standards such as ISO Standard 13006, PNS154-2005, and ICCTAS ESTD 1990.

All the materials except NiLaMW exhibited melting behavior at temperatures below 1200°C, which means that they can be used as a source of fluxes. The results demonstrated that all formulations were highly vitreous, with a very low average water absorption of less than 0.03% and a MOR ranging from 42.71MPa to 46.25MPa, thus presenting their potential for vitreous ceramic applications.

Natural zeolite (NZ) offers unique surface properties that enable its use in environmental remediation and catalytic applications. In this study, a graphene oxide/natural zeolite/bismuth oxide (GO/NZ/Bi₂O₃) composite was developed to enhance the functional performance of NZ for the photocatalytic degradation process relevant to environmental treatment. The composite was synthesized through a two-step calcination process: NZ was first calcined with bismuth oxide (Bi₂O₃) at 900 °C to form the NZ/Bi₂O₃ composite, followed by graphene oxide (GO) incorporation and a secondary calcination at 300 °C. Structural characterization revealed apatite-type and eulytite mineral phases in the NZ/Bi₂O₃ system, reflecting phase transformations arising from high-temperature interaction between NZ and Bi₂O₃. Incorporation of GO resulted in a dominant calcium bismuth oxy-silicate phase. FTIR spectra confirmed characteristic Si–O–Si and Si–O–Al vibrations inherent to natural zeolite, alongside Bi–O and C–O bands indicative of successful composite formation. SEM analyses showed porous NZ structures supporting agglomerated Bi₂O₃ particles and irregular GO flakes, while TGA-DTG identified thermal events associated with moisture release, NZ-bound water, GO degradation, and Bi₂O₃ transitions. BET measurements exhibited a Type IV isotherm and a surface area of 1.06 m²/g, consistent with mesoporous mineral composites. Zeta potential data revealed reduced suspension stability following GO integration. Notably, the GO/NZ/Bi₂O₃ composite demonstrated superior photocatalytic degradation efficiency, underscoring the enhanced reactivity achieved through synergistic modification of natural zeolite. Overall, this work highlights the geochemical adaptability of natural zeolite and its potential for advanced environmental applications.

Silt from mining siltation ponds poses environmental risks and hazards, necessitating research into sustainable valorization techniques. One of the unexplored ways to do so is to use them as sustainable fillers for polymer composites. This study investigates the use of silt from mine waste, sourced from siltation ponds of a mining company in the southern Philippines, as a sustainable filler in unsaturated polyester resin (UPR) composites to advance a circular economy. The silt, processed to <1 micron and treated with sodium silicate, was incorporated at 1%, 3%, and 5% weight percentages. Composites underwent tensile and flexural strength tests, with silt characterized by FTIR and XRD to confirm compatibility.

Tensile tests revealed that the 5% filler composite had the highest Young's modulus (437.064 MPa) and toughness (361.473 J/m³), surpassing the UPR control (308.363 MPa and 322.866 J/m³). Flexural tests showed that the 1% filler composite had the highest flexural modulus (1276.413 MPa) and maximum stress (58.716 MPa), while the 3% filler composite balanced stiffness (1061.621 MPa), strength (47.890 MPa), and toughness (617.153 J/m³). ANOVA confirmed significant differences in tensile (p=0.019) and flexural properties (p=0.007). Fracture analysis using a digital microscope indicated mixed brittle and ductile mechanisms, with rougher surfaces in higher filler composites suggesting improved energy dissipation. FTIR and XRD verified silt’s suitability, with the presence of phyllosilicates detected in the sample. Future work should include SEM analysis of fractured surfaces to investigate microstructural interactions and a UTM with higher capacity to accurately assess compressive strength. These findings reveal that mine waste-derived silt can be used as a sustainable filler for enhancing UPR composite mechanical properties, supporting eco-friendly material development.

Rock-Eval (RE) analysis has conventionally been employed as a standard and rapid screening technique in the O&G sector to assess the properties of source rocks. The method relies on thermal decomposition of samples through two heating steps (pyrolysis and combustion), during which released gases (CO, CO₂, HCs, and SO₂) are continuously detected by specific sensors. This study evaluated the applicability of RE as a screening tool for assessing CO₂ conversion into carbonates in the context of carbon mineralization in basalts. For this purpose, after developing a two-step experiment (dissolution and precipitation) using powdered basalt from the Serra Geral Group (Paraná–Etendeka Large Igneous Province), a fraction of the samples was analyzed with the RE instrument to evaluate the CO₂ release profile during heating from 300 °C to 850 °C. The analysis revealed a pattern that is characteristic of carbonates, with decomposition peaks above 650 °C. The amount formed during the experiments was quantified by converting the CO₂ peak into an equivalent calcite mass. This conversion was based on a calibration curve established from known quantities of pure calcite added to a basaltic matrix, allowing for the correlation of the CO₂ signal intensity to the carbonate content. Calculations confirmed that the estimated values were consistent with the CO₂ release observed in the RE profiles. Based on signal intensity, the experimental samples were classified into three groups: G1, with low values (< 500 mV); G2, with moderate values (500–3000 mV); and G3, characterized by high values (> 3000 mV). To complete the workflow, SEM/EDS analyses provided visual confirmation of the carbonate precipitates indicated by RE. The results demonstrate that this approach is a rapid and effective tool for detecting and quantifying mineralized CO₂ in basaltic rocks.

Production of ceramics involves multiple stages, among which sintering is critical for achieving desired properties. The sintering environment, particularly the sintering atmosphere, influences the densification and phase transformation of ceramics. Understanding the phase transformation and densification is essential for optimizing the microstructure and performance of the final ceramic products. This study investigated the effect of sintering atmosphere on the densification and phase transformation of the binary composition of red clay and black cinder. Red clay and black cinder are iron-rich silicates abundant in Lanao del Norte, Philippines. They were mixed in varying proportions, dry-pressed, and sintered at 1200°C under oxidizing (air) or inert (argon) atmospheres. Densification was evaluated through water absorption (WA) and apparent porosity (AP), while mechanical strength was evaluated via the Modulus of Rupture (MOR) test. Phase composition and microstructure were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM).

Argon-sintered samples exhibited enhanced densification, with water absorption and apparent porosity of 0.011% and 0.02%, respectively, compared to 0.25% WA and 0.43% AP in air-sintered samples. Correspondingly, the MOR increased by an average of 25%, reaching up to 47.57 ± 4.18 MPa under argon versus 36.77 ± 2.15 MPa in air. XRD results showed distinct phase differences between air- and argon-sintered samples. In air, the phases present were tridymite, mullite (Al₆Si₂O₁₃), and cristobalite (SiO₂ polymorph), while in argon, cristobalite was absent, with new observed phases of hercynite (FeAl₂O₄) and bytownite (CaAl₂Si₂O₈). SEM observations further confirmed a denser microstructure in argon-sintered samples. In conclusion, sintering atmosphere affects the densification and phase transformation of red clay–black cinder ceramics. Argon-sintered samples demonstrate enhanced densification and higher strength, suggesting potential applications in high-strength ceramics and refractories for preliminary kiln linings in basic environments, with performance under actual operating conditions requiring further assessment.

Thorianite (ThO₂) is a naturally occurring mineral form of thorium dioxide found in diverse geological settings such as pegmatites, carbonatites, and heavy mineral sands. The environmental importance of the material lies in the fact that the mobility of thorium species in the mineral weathering and hydrolysis processes is likely to reduce the quality of groundwater and radiochemical stability. This study aims to computationally investigate the hydrolysis and hydrolysis and aqueous stability behavior of Th⁴⁺ and hydrated ThO₂ complexes to understand their stability and potential environmental implications. Density functional theory (DFT) calculations were performed using Gaussian 09W, Revision D.01 to simulate the hydrolysis of Th⁴⁺ and ThO₂(H₂O)ₙ species (n = 1 to 10). The relative stabilities and electronic characteristics of the hydrated thorium species, optimised geometries, total electronic energies, and thermodynamic parameters, such as entropy and Gibbs free energy, were calculated. The coordination number of Th⁴⁺ was found to be decreasing progressively during stepwise hydrolysis. Among the hydrated species, ThO₂(H₂O)₉ exhibited the highest stability with a total energy of −29764.9950 eV and total free energy of −20701.0604 eV, indicating strong hydration stabilization. ThO₂(H₂O)₆, possessing C₂v symmetry, shows a total energy of −23539.8782 eV and entropy of −865.8066 cal mol⁻¹K⁻¹. The results suggest that hydration plays a critical role in stabilizing thorium oxide clusters, which can influence thorium mobility under aqueous conditions. The computational insights highlight that the hydrolysis of ThO₂ can yield stable hydrated complexes, which may enhance thorium solubility and potential leaching into groundwater systems. These findings contribute to understanding the environmental geochemistry of thorium-bearing minerals and their long-term behavior in natural waters. The study underscores the importance of quantum chemical modeling in predicting mineral water interactions relevant to radioactive element dispersion and environmental safety.

The Cloisite Na-Montmorillonite (CNa-MMT) available in the market contains other silicates, such as beidellite, quartz, cristobalite and tridymite. This study explores the potential of electrophoretic deposition (EPD) to improve the purity of CNa-MMT as an important nanoclay filler of nanocomposites, at least for construction materials, food containers, environmental remediation, wound management and sports gear applications. A program of procedures was developed using AUTOLAB p/g for the conduct of EPD. Stainless steel strips were used as electrodes during EPD. XRD of EPD deposits was performed using a Shimadzu XRD-700 with a copper target. Two levels of applied potential were used: high potential “HP”, low potential “LP”, and electrode gap; high electrode gap “HeG” and low electrode gap “LeG”, were investigated for their effects on the yield and purity of CNa-MMT deposits. Analysis of Variance for the two-factor fixed effect model was performed to determine the effects of the factors and their interaction on the yield of CNa-MMT EPD deposits at a 95% confidence level. Results showed significant effects of applied potential, electrode gaps and their interaction on the yield and purity of CNa-MMT. The specific combination of HP-LeG resulted in the highest yield of Na-MMT deposits, while low potential levels (LP) at any electrode gap had a low yield. Interaction plots also showed that low gap (LeG) has a higher slope than high gap (HeG), suggesting that a slight increase in applied potential at a low electrode gap (LeG) will result in a higher increase in the dry Na-MMT EPD deposit than with the same level of potential at a high electrode gap (HeG). Results further showed that even though HP-HeG and LP-LeG experienced the same effect of the electric field, HP-HeG resulted in a higher yield than LP-LeG. Furthermore, XRD showed that the dry Na-MMT EPD deposits swelled and attained higher purity than the commercially available Cloisite Na-MMT.