Silicate Materials Research Articles

Salty chemical cocktails as water quality signatures: Longitudinal trends and breakpoints along different U.S. streams

Along urban streams and rivers, various processes, including road salt application, sewage leaks, and weathering of the built environment, contribute to novel chemical cocktails made up of metals, salts, nutrients, and organic matter. In order to track the impacts of urbanization and management strategies on water quality, we conducted longitudinal stream synoptic (LSS) monitoring in nine watersheds in five major metropolitan areas of the U.S. During each LSS monitoring survey, 10–53 sites were sampled along the flowpath of streams as they flowed along rural to urban gradients. Results demonstrated that major ions derived from salts (Ca2+, Mg2+, Na+, and K+) and correlated elements (e.g. Sr2+, N, Cu) formed ‘salty chemical cocktails’ that increased along rural to urban flowpaths. Salty chemical cocktails explained 46.1% of the overall variability in geochemistry among streams and showed distinct typologies, trends, and transitions along flowpaths through metropolitan regions. Multiple linear regression predicted 62.9% of the variance in the salty chemical cocktails using the six following significant drivers (p < 0.05): percent urban land, wastewater treatment plant discharge, mean annual precipitation, percent silicic residual material, percent volcanic material, and percent carbonate residual material. Mean annual precipitation and percent urban area were the most important in the regression, explaining 29.6% and 13.0% of the variance. Different pollution sources (wastewater, road salt, urban runoff) in streams were tracked downstream based on salty chemical cocktails. Streams flowing through stream-floodplain restoration projects and conservation areas with extensive riparian forest buffers did not show longitudinal increases in salty chemical cocktails, suggesting that there could be attenuation via conservation and restoration. Salinization represents a common urban water quality signature and longitudinal patterns of distinct chemical cocktails and ionic mixtures have the potential to track the sources, fate, and transport of different point and nonpoint pollution sources along streams across different regions.

Silicate brick production using anhydrite raw material

Purpose: The aim of this work is to substantiate recycling of anhydrite raw materials for the production of silicate products and the development of methods for preparing source materials, compositions and process modes.Methodology/approach: Selection and research of basic materials, methods of their preparation for the production of silicate products; justification of process methods and assessment of quality parameters of materials with the required properties.Research findings: The possibility of utilizing acid fluoride during the synthesis of calcareous-siliceous binder used to produce silicate bricks during autoclave processing. The obtained sand-lime brick samples possess the following physical and mechanical properties: 1750 to 1900 kg/m3 average density, 10 to 12.5 MPa compressive strength, 16 or 17 % water absorption. The samples meet the requirements for sand-lime bricks, namely strength, density, water absorption and correspond to grades 100 and 125.Practical implications: The process modes of autoclaving are detected and the main operational characteristics of sand-lime brick are determined. Methods proposed for preparing raw materials and process conditions of silicate wall materials allow solving environmental problems and saving natural limestone raw materials.Novelty: Sand-lime brick production is based on anhydrite raw materials; suggested dependencies make it possible to control the composition and properties of silicate materials.

Adsorption of Co2+ and Cr3+ in Industrial Wastewater by Magnesium Silicate Nanomaterials.

In this paper, two flower-like magnesium silicate nanomaterials were prepared. These and another two commercial magnesium silicate materials were characterized using a scanning electron microscope, the N2 adsorption-desorption method, and other methods. The structure-activity relationship between the adsorption performance of these four magnesium silicate materials and their specific surface area, pore size distribution, and pore structure was compared. The results showed that the 3-FMS modified by sodium dodecyl sulfonate (SDS) had the largest specific surface area and pore size, the best adsorption performance, and the largest experimental equilibrium adsorption capacity (qe,exp) for Co2+, reaching 190.01 mg/g, and Cr3+, reaching 208.89 mg/g. The adsorption behavior of the four materials for Co2+ and Cr3+ both fitted the pseudo-second-order kinetic model and Langmuir adsorption model, indicating that chemical monolayer uniform adsorption was the dominant adsorption process. Among them, the theoretical adsorption capacity (qm) of 3-FMS was the highest, reaching 207.62 mg/g for Co2+ and 230.85 mg/g for Cr3+. Through further research, it was found that the four materials mainly removed Co2+ and Cr3+ through electrostatic adsorption, surface metal ions (Mg2+), and acidic groups (-OH and -SO3H) exchanging with ions in solution. The adsorption performance of two self-made flower-like magnesium silicate materials for Co2+ and Cr3+ was superior to that of two commercial magnesium silicates.

Biological and Mechanical Performance of Dual-Setting Brushite-Silica Gel Cements.

Bone defects resulting from trauma, diseases, or surgical procedures pose significant challenges in the field of oral and maxillofacial surgery. The development of effective bone substitute materials that promote bone healing and regeneration is crucial for successful clinical outcomes. Calcium phosphate cements (CPCs) have emerged as promising candidates for bone replacement due to their biocompatibility, bioactivity, and ability to integrate with host tissues. However, there is a continuous demand for further improvements in the mechanical properties, biodegradability, and bioactivity of these materials. Dual setting of cements is one way to improve the performance of CPCs. Therefore, silicate matrices can be incorporated in these cements. Silicate-based materials have shown great potential in various biomedical applications, including tissue engineering and drug delivery systems. In the context of bone regeneration, silicate matrices offer unique advantages such as improved mechanical stability, controlled release of bioactive ions, and enhanced cellular responses. Comprehensive assessments of both the material properties and biological responses of our samples were conducted. Cytocompatibility was assessed through in vitro testing using osteoblastic (MG-63) and osteoclastic (RAW 264.7) cell lines. Cell activity on the surfaces was quantified, and scanning electron microscopy (SEM) was employed to capture images of the RAW cells. In our study, incorporation of tetraethyl orthosilicate (TEOS) in dual-curing cements significantly enhanced physical properties, attributed to increased crosslinking density and reduced pore size. Higher alkoxysilyl group concentration improved biocompatibility by facilitating greater crosslinking. Additionally, our findings suggest citrate's potential as an alternative retarder due to its positive interaction with the silicate matrix, offering insights for future dental material research. This paper aims to provide an overview of the importance of silicate matrices as modifiers for calcium phosphate cements, focusing on their impact on the mechanical properties, setting behaviour, and biocompatibility of the resulting composites.

Transforming Natural Eggshell and Diatomite into Bioactive Calcium Silicate Material for Bone Regeneration.

Calcium silicate (CS), a new and important bioceramic bone graft material, is prepared by using eggshells, which have a porous structure and are rich in calcium ions. Furthermore, the preparation of new CS materials using eggshells and diatomaceous earth minimizes their negative impact on the environment. In this study, we prepared CS materials using a high-temperature calcination method. The composition of the material was demonstrated by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analysis. Scanning electron microscopy (SEM) analysis confirmed the porous structure of the CS material. We also introduced ZnO to prepare ZnO-CS with antibacterial properties and showed that ZnO-CS exhibits excellent antibacterial effects through in vitro antibacterial experiments. Subsequent in vitro mineralization experiments demonstrated that ZnO-CS promoted the formation of a hydroxyapatite layer. Furthermore, in vitro cytotoxicity experiments demonstrated that ZnO-CS had very good biosafety and promoted cell proliferation. These findings were confirmed through subsequent cell proliferation experiments. Our results indicate that the novel ZnO-CS is a promising candidate for bone tissue engineering.

Effect of the boson peak and the ionic resonance in the dielectric properties of silicate materials at mm-wave and THz frequencies

In this paper, a broadband measurement of the dielectric properties of silicates has been done to cover the seldom characterized mm-wave spectrum and the low THz spectrum. The dielectric properties, i.e. loss and permittivity, show a frequency independent response up to approximately 40 GHz and the loss monotonically increases to the THz frequency range. Two resonance peaks appear at THz frequencies: the first is the boson peak, and the second one corresponds to the ionic resonance of the network former, which in this case is silicon. Even though the materials belong to different groups in the silicate family (crystalline and non-crystalline, with different levels of purity), they seem to have the same overall tendency in the dielectric properties. Argand plots are used for the first time at THz frequencies to provide physical insight into the boson peak and ionic resonance. The complex plane analysis reveals details on the polarization mechanisms underlying silicate network vibrations through direct visualization of their characteristic signatures, and simplifies the process of modeling the dielectric response, leading to a better fit.

The Effect of Chitosan Incorporation on Physico-Mechanical and Biological Characteristics of a Calcium Silicate Filling Material.

A tricalcium silicate-based cement, Biodentine™, has displayed antibiofilm activity when mixed with chitosan powder. This study aimed to assess the effect of chitosan incorporation on the physico-mechanical and biological properties of Biodentine™. In this study, medium molecular weight chitosan powder was incorporated into Biodentine™ in varying proportions (2.5 wt%, 5 wt%, 10 wt%, and 20 wt%). The setting time was determined using a Vicat apparatus, solubility was assessed by calculating weight variation after water immersion, radiopacity was evaluated and expressed in millimeters of aluminum, the compressive strength was evaluated using an Instron testing machine, and the microhardness was measured with a Vickers microhardness tester. In addition, surface topography of specimens was analyzed using scanning electron microscopy, and the effect of chitosan on the viability of human embryonic kidney (HEK 293) cells was measured by a colorimetric MTT assay. Incorporation of 2.5 wt% and 5 wt% chitosan powder delivered an advantage by speeding up the setting time of Biodentine material. However, the incorporation of chitosan compromised all other material properties and the crystalline structure in a dose-dependent manner. The chitosan-modified material also showed significant decreases in the proliferation of the HEK 293 cells, signifying decreased biocompatibility. Chitosan incorporation into calcium silicate materials adversely affects the physical and biological properties of the material. Despite the increased antimicrobial activity of the modified material, the diminution in these properties is likely to reduce its clinical value.

Enhancing physico-mechanical properties and thermal stability of geopolymer composites through nano-material incorporation

Influence of various types of nano powder on the physico-mechanical properties of geopolymer materials has been studied, in addition to studying their firing stability up to 1000 °C. Alumino–silicate materials used are kaolin, fired kaolin and lime stone. Materials prepared at water/binder ratios of 0.40; whereas the used equal volume of activator 5 M sodium hydroxide with liquid sodium silicate. Nano-kaolin admixed with Nano-powder as a partial replacement from metakaolin material. The control mixes incorporating either 7% Nano-glass or 5% Nano-silica fume. Nano-kaolin was partially replaced Nano-glass powder and Nano-silica fume. It is possible to use the mixes containing limestone and nano materials to solve the problem of using heat curing, thermal energy consumption and pollution by reducing the MK used for MK-geopolymer cement. Results indicated an enhancement in the physico-mechanical properties of mix incorporating 1: 6% and 2:3% of NK:N-glass and NK:N-silica fume, respectively. Firing of hardened geopolymer resulted in high thermal resistance up to 700 °C then exposed to decrease up to 1000 °C. However, no micro-cracks were noticed up to 800 °C for all samples as recorded by visual examination of the fired samples, while micro-cracks were recorded for hardened composites at 1000 °C.Graphical

Siliceous waste material supported MOF-5 for carbon monoxide capture at low temperature

Siliceous waste material supported MOF-5 for carbon monoxide capture at low temperature

Silica extracts from fly ash modified via sol-gel methods and functionalized with CMPO for potential scavenging of rare earth elements La³⁺ and Ce³⁺

A mesoporous material was synthesized using silica extracts from fly ash and its properties were studied. Subsequently, it was functionalized with carbamoylmethylphosphine oxide (CMPO) to capture La3+ and Ce3+. The developed mesoporous material was obtained by the sol-gel method and was called Si-MMS (siliceous mesoporous materials), subsequently functionalized with APTMS (1-(2-aminoethyl)-3-aminopropyl trimethoxysilane) in a reflux system, which led to the synthesis of Si-MMS-APTMS. This derivative was modified with carbonyldiimidazole (CDI) and diethylphosphonoacetic acid, which finally resulted in the synthesis of Si-MMS-CMPO as the final product. The materials were characterized by DRIFT, XRD, SEM-EDS, TEM, XPS, elemental analysis and nitrogen isotherms at −196 °C, confirming that the synthesis and subsequent modification of the mesoporous structure was successful. Adsorption studies in batch systems indicated that the optimal pH for La3+ was 6, the Langmuir isotherm model and the non-linear Sips models were perfectly fitted and the best fitting kinetics is the Elovich model. For Ce3+ the optimal pH was 7.5, the non-linear Sips isotherm fit the best and the non-linear Pseudo-second order kinetics was the mechanism that best represents the adsorption. The maximum experimental adsorption capacity qe of La3+ was 17.00 mg g−1 and for Ce3+ was 30.09 mg g−1. In both cases, the rapid adsorption suggests an open porous matrix that facilitates the formation of chelates between the adsorbates and the phosphoryl group -PO32-.

Authigenic Barite in Tailing Dumps: Mineralogical and Geochemical Data and Results of Physico-Chemical Modeling

On the example of the Novo-Ursk tailing dump (Salair Ridge), the typomorphic characteristics of barite are considered. It was found that in the dumps, in addition to residual barite from pyrite-polymetallic ores, there are its authigenic varieties. Ore barite grains are found in the form of fragments of irregular shapes, less often grains of a tabular habit, have a dimension of 50–400 microns, Sr up to 1.41 wt.%. Newly formed barite occurs as single grains or clusters of round and elongated shapes or acicular crystals, ranging in size from 1–2 µm to larger aggregates that form veinlets or clusters in the siliceous matrix in association with jarosite and/or anhydrite. Among the impurities, Pb up to 6.33 wt.% was noted, less often Fe up to 0.73 wt.%, Sr up to 0.94 wt.%. It was shown by using thermodynamic modeling that the concentrations of Ba, SO4, Fe and Ca in solution vary within several orders of magnitude when the mineral composition of the tailings mound zones changes depending on the Eh–pH conditions of their formation. It has been suggested that the formation of barite along with pyrite may occur as a result of the action of a reductive biogeochemical barrier or a sulfate concentration barrier in the deeper parts of the section where supersaturation is achieved.The most informative typomorphic feature proving that barite was formed under tailings conditions is particle morphology, mineral association and chemical composition.

Nanoporous aluminosilicate mediated synthesis of 2- and 2,2-substituted 2,3-dihydroquinazolin-4(1H)-ones

Nanoporous silicate materials, made by an operationally simple evaporation-induced self-assembly (EISA) approach, efficiently catalyze the formation of 2-substituted 2,3-dihydroquinazolin-4(1H)-ones from aldehydes and dimethyl acetals. This methodology can be extended to encompass the reaction of ketones and ketals to provide facile access to 2,2-disubstituted and spiro dihydroquinazolin-4(1H)-ones in high yields and short reaction times.

Clean-up of divalent cobalt ions by massive sequestration in a low-cost calcium silicate hydrate material

Cobalt is a critical resource in industrial economies for the manufacture of electric-vehicle batteries, alloys, magnets, and catalysts, but has acute supply-chain risks and poses a threat to the environment. Large-scale sequestration of cobalt in low-cost materials under mild conditions opens a path to cobalt recycling, recovery and environmental clean-up. We describe such sequestration of cobalt by a widely available commercial calcium silicate material containing the mineral xonotlite. Xonotlite rapidly and spontaneously takes up 40 percent of its weight of cobalt under ambient conditions of temperature and pressure and reduces dissolved cobalt concentrations to low parts per million. A new Sharp Front experimental design is used to obtain kinetic and chemical information. Sequestration occurs by a coupled dissolution-precipitation replacement mechanism. The cobalt silicate reaction product is largely amorphous but has phyllosilicate features.

Frequency-based electric fingerprint and thermal properties of the NWA 869 chondrite

The NWA 869 chondrite is among many common stony regolith breccia meteorites that have been collected from northwest Africa (NWA). It is composed of Fe sulphide and Fe-Ni metallic phase inclusions embedded in a silicate stony matrix (primarily pyroxene). Although the physical properties of meteorites are the implementation of their mineral and chemical compositions, their electric and dielectric properties (electric conductivity σ, dielectric constant ε′, and dielectric loss ε") are rarely studied, while no literature has been published on their thermal properties (thermal conductivity K, thermal diffusivity α, specific heat capacitance Cp, and thermal effusivity e). Consequently, the present study deals with studying the electric and dielectric properties of the NWA 869 chondrite at a frequency range (4.0 Hz-8.0 MHz), and their behavior against the applied frequency (fingerprint) was matched. Also, the thermal properties were measured at the ambient conditions. The porosity and density of the chondrite were also measured using helium injection technique. To explain the electric and thermal properties of the meteorite sample, its internal structure as well as its mineral and chemical compositions were revealed using the environmental Scanning electron microscopy (ESEM) supported by the EDAX technique. It is indicated that the chondrite is composed of iron sulphide and Fe-Ni inclusions scattered in a stony silicate matrix; it is characterized by moderate density (3.5069 g/cc) with a considerable porosity value (2.12 %). It is also characterized by moderate electric conductivity (σ), dielectric constant (ε′), and dielectric loss (ε") values (0.50 < σ < 2037.3 ohmm, 67.0 < ε' < 1713.7, and 0.22 < ε" < 12,432 at frequency range 4 Hz-8MHz, respectively). Also, it is characterized by thermal conductivity (K), thermal diffusivity (α), thermal capacitance (Cp), and thermal effusivity (e) values of average 1.5185 W/(K.m), 1.5425 mm2/s, 286 J/(K.kg), and 2628 W(s)0.5/m2K, respectively.

Metallic nickel exsolved from a two-dimensional MWW-type zeolitic nickel silicate: An effective catalyst for ammonia decomposition

Exsolution of active species from metal oxide materials is an effective strategy for preparing a highly active and stable catalyst. Here, we prepared two-dimensional nickel (Ni) silicate material with delaminated MWW layers (Ni-DMLs) by hydrothermal treatment of borosilicate MWW precursor (B-MWW(P)) with Ni nitrate solutions and applied on the catalytic decomposition of ammonia (NH3) via exsolution. The layered B-MWW(P) was transformed to a three-dimensional (3D) tectosilicate MWW, a two-dimensional (2D) Ni-DML, and a 2D phyllosilicate structures at temperature regions of 100–120 °C, 140–160 °C, and 170–180 °C, respectively. Meanwhile, the Ni contents on the samples increased from 3.6 to 37.6 wt.% as the hydrothermal temperature increased from 100 to 180 °C, owing to the substitution of framework B by Ni. The chemical state of Ni on each sample was characterized by various analytical tools and correlated with their catalytic properties of NH3 decomposition over the exsolved metallic Ni species. The NH3 decomposition over Ni-DMLs was evaluated in the temperature range of 300–600 °C, and the apparent activation energies were compared. The Ni-DML-160 exhibited the best catalytic activity, achieving an NH3 conversion of 70% at 500 °C and maintained 90% to initial conversion during 100 h on stream at 550 °C. The synergistic effect of the strong interaction between the exsolved metallic Ni and the zeolite support and the 2D nature of Ni-DMLs relieved the catalytic deactivation by sintering and coking, respectively.

Ruthenium supported on silicate and aluminosilicate mesoporous materials applied to selective sugar hydrogenation: Xylose to xylitol

A series of ruthenium-based catalysts supported on a set of silicate and aluminosilicate mesoporous molecular sieves was synthesized and tested in xylose hydrogenation. The materials were characterized in terms of morphology, textural properties, acidity, as well as ruthenium loading, dispersion, and oxidation state. In general, the aluminosilicates-based catalysts displayed a higher activity compared to their respective silicate supports, which can be ascribed to a higher Ru content and dispersion, enhanced by a higher acidity. The most active synthesized catalyst (Ru/Al-MCM-4) displayed an improved performance compared to a commercial Ru/C catalyst due to a better xylitol selectivity. Two modelling approaches were implemented to describe the kinetic rate. The first model was based on the hypothesis that xylose molecules and hydrogen are adsorbed in different active sites on the catalyst surface, while the second model supposes the formation of an intermediate on the catalyst surface that reacts to form xylitol. Both models gave a very good description of the experimental data.

Synthesis and characterization of surface-modified magnetic mesoporous silicate materials for phosphate adsorption.

The magnetic mesoporous silica material, Mag-MCM-41, was synthesized by coating magnetite (Fe3O4) nanoparticles with a mesoporous material called MCM-41. Mag-MCM-41 and modified nanomaterials Mag-MCM-41-NN and Mag-MCM-41-NN-Fe+3 which were modified with aminopropyl functional groups. In water and wastewater, phosphate anions are considered significant contaminants due to their detrimental impact on the environment. They promote the growth of algae, leading to eutrophication. The purpose of this study is to investigate the removal of phosphate anions from aqueous solutions using modified magnetic silica particles. The Mag-MCM-41 material exhibits hexagonal properties and belongs to the class of "mesoporous" materials. It has a surface area of 923 m2.g-1, which was determined through N2 adsorption-desorption isotherms, FTIR, TEM, BET, and SAXS analysis. Kinetic and adsorption isotherm studies were conducted using Mag-MCM-41, Mag-MCM-41-NN, and Mag-MCM-41-NN-Fe+3 adsorbents to examine the behavior of phosphate anions. The kinetic and adsorption isotherm studies of phosphate anions revealed that the adsorption process on Mag-MCM-41, Mag-MCM-41-NN, and Mag-MCM-41-NN-Fe+3 adsorbents followed the chemical adsorption mechanism. Phosphate adsorption on all adsorbents occurred in a monolayer, and the MCM-41-NN-Fe+3 adsorbent exhibited the highest maximum adsorption capacity (qm) value of 112.87 mg.g-1 compared to the other adsorbents.

Research Progress in Mechanochemistry of Inorganic Materials

With the progress of science and technology, China has gradually attached importance to research and exploration in chemistry, and the achievements in exploring mechanochemistry are also quite significant. Therefore, it is necessary to study and explore mechanochemistry. This article mainly discusses the application of mechanochemistry in powder and some silicate materials, as well as in special ceramics, and provides a brief introduction to provide reference for relevant researchers.

Dynamics of pH&lt;sub&gt;KCl&lt;/sub&gt; of calcified sod-podzolic sandy loam soil by meliorants of various chemical nature

The possibility of accelerating the reaction of meliorant-freshly calcified soil in a solution of 1 n. KCl is shown. Changes in the pH value during 20 days of soil-solution interaction were traced. Differences in the reaction rate have been established when using ameliorants of various chemical nature for liming. It was revealed that the reclamation effect when using silicate materials in the experiment was less than that of carbonate. According to the effect achieved as a result of liming, all meliorants used in the experiment can be arranged in the following descending order: dolomite flour (DF), crushed stone screening (CSS) conversion chalk (CC), dolomitized limestone flour (DLF) blast furnace slag (BFS) shale ash (SA). Empirical models of changes in the pHKCl value over the entire experimental interval have been developed for all lime fertilizers. Clustering of individual variants of the experiment, produced by various meliorants, according to their effect on the pHKCl index over the entire period of study was carried out.

Growth of Urochloa grass in an oxisol treated with powdered silicate materials

An experiment was carried out in pots with a soil mixed with six powdered silicate materials originated from mining (kyanite, biotite schist, biotite syenite, basalt, vermiculite, or bentonite). These sources were mixed in 4.4 kg of soil (Anionic Acrustox) at the rates of 0 (control), or 440 g of ground silicate materials, in pots where Urochloa decumbens cultivar Basilisk was grown. The grass growth followed the relative total dry mass (%): 100 &gt; 93.8 &gt; 82.7 &gt; 71.4 &gt; 54.4 &gt; 9.4 &gt; 6.8 for biotite schist, bentonite, vermiculite, basalt, syenite, kyanite, and soil (control), respectively. Soil pH (6.5) ultimately decreased Mn availability to plants. Although some silicate materials increased Mn availability to plants, increasing treated plants growth, it was not possible to evaluate if plants were able to acquire more P when treated with silicate materials. Concentrations of Fe and P extracted from the soil and from shoots were highly correlated with dry mass. The reactivity of these materials in soils increasing soil pH may be an important parameter for ranking agrominerals, as the availability of nutrients was correlated to the amount of carbonate used to increase pH of the treated soil to 6.5.