2,856 results on '"Diatomite"'
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2. Geology, microstratigraphy, and paleontology of the lacustrine Truckee Formation diatomite deposits near Hazen, Nevada, USA, with emphasis on fossil stickleback fish
- Author
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Cerasoni, Jacopo Niccolò, Bell, Michael A., and Stuart, Yoel E.
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Miocene ,Paleobiology ,Evolution ,Geomorphology ,Diatomite ,Phytoliths - Abstract
Diatomite deposits of the lacustrine Truckee Formation near Hazen, Northern Nevada, are of Miocene age (ca. 10.3 million years old) and consist of varved deposits within commercial mines. These exposed deposits have been primary source of paleontological samples of stickleback fish fossils (Gasterosteous doryssus) spanning 100,000 years. These samples have revealed stasis, rapid morphological and genetic evolution, and local extinction of G. doryssus against a background of changing diatom communities. Here, we draw on geological, limnological, anthropogenic, and bibliographical data to illustrate the geographic and paleontological context of the Hazen diatomite deposits. We include a stratigraphic section describing lithology and stickleback specimen frequency at a 1 mm resolution. This paper should help researchers identify patterns in fossil site distribution and better understand the geological processes that have shaped the area, spurring new sampling and future research.
- Published
- 2024
3. Regulating pore structure of diatomite with alkali dissolution and its influence on humidity control performance.
- Author
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Hu, Zhibo, Wen, Xingqing, Zheng, Shuilin, Yin, Jiayi, Shen, Xinyu, and Zhang, Tiancheng
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HUMIDITY control , *POROSITY , *DIATOMACEOUS earth , *POROUS materials , *HYDROXYL group - Abstract
Alkali dissolution is an effective method to regulate the pore structure of porous mineral material. The main chemical composition of diatomite is amorphous SiO 2 , which can be dissolved in alkali dissolution. The diatomite samples with alkali dissolution treatment were systematacially characterized by the particle size analysis, low temperature nitrogen adsorption, MIP, fractal theory, SEM, TEM, XRD, FTIR and surface hydroxyl density to analyze the pore structure and surface properties. And the humidity control performance of diatomite was tested under different temperatures and relative humidities. The relationship among pore structure, surface properties and humidity control performance were analyzed. The results show that alkali dissolution can regulate the mesoporous and macroporous of diatomite, and some new microporous can generate at high alkali dosage. The specific surface area, mesoporous pore volume, proportion of macroporous volume, surface roughness, heterogeneity of pore structure and number of hydroxyl groups on the surface of diatomite are important factors which determining the humidity control performance. The humidity control performance of diatomite is positively correlated with the specific surface area, mesoporous volume, surface roughness, heterogeneity of pore structure and number of hydroxyl groups on the surface, while is negatively correlated with the proportion of macroporous volume. [ABSTRACT FROM AUTHOR]
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- 2024
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4. Glycidyl methacrylate-modified diatomite as reinforcing filler for natural rubber composite.
- Author
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Zhao, Meng, Duan, Hao, Han, Linfeng, Zhang, Lin, Peng, Keyu, Jing, Yuan, Borah, Jyotishmoy, and Lin, Guangyi
- Abstract
Glycidyl methacrylate (GMA) was grafted onto diatomite (DE) to improve the interfacial bonding between GMA and rubber using "one-step"/"two-step" methods, respectively. The hydroxyl group on DE and the amine group on γ-aminopropyltriethoxysilane (KH550) react with the epoxy group on GMA in a ring-opening reaction during the process. The modified diatomite was characterized and analyzed by using Fourier transform infrared spectroscopy (FT-IR), X-ray fluorescence spectrometer (XRF), X-ray diffraction patterns, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). Natural rubber/diatomite (NR/DE) composites were also prepared using a wet mixing method and investigated the interfacial interactions between different DE and NR in detail using dynamic mechanical analysis (DMA) and rubber process analyzer (RPA). The result showed the improved mechanical properties of NR/DE composites for both "one-step" and "two-step" methods; however, the "two-step" method is found to be more effective. Compared with the unmodified NR/DE composites, the "two-step" modified NR/DE composites exhibited an increase in 37.8% tensile strength, 25.1% tear strength, 11.7% abrasion resistance, and 24% wet slip resistance, respectively. In addition to these, GMA has minimal effect on the elongation at break retention of the rubber composites after aging. These results showed valuable insights for the further application of diatomite in rubber. [ABSTRACT FROM AUTHOR]
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- 2024
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5. Diatoms in Focus: Chemically Doped Biosilica for Customized Nanomaterials.
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Vicente‐Garcia, Cesar, Vona, Danilo, Flemma, Annarita, Cicco, Stefania Roberta, and Farinola, Gianluca Maria
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DIATOMACEOUS earth , *DIATOMS , *ENERGY conversion , *ENERGY storage , *NANOPORES - Abstract
Diatoms are photosynthetic microalgae widely diffused around the globe and well adapted to thrive in diverse environments. Their success is closely related to the nanostructured biosilica shell (frustule) that serves as exoskeleton. Said structures have attracted great attention, thanks to their hierarchically ordered network of micro‐ and nanopores. Frustules display high specific surface, mechanical resistance and photonic properties, useful for the design of functional and complex materials, with applications including sensing, biomedicine, optoelectronics and energy storage and conversion. Current technology allows to alter the chemical composition of extracted frustules with a diverse array of elements, via chemical and biochemical strategies, without compromising their valuable morphology. We started our research on diatoms from the viewpoint of material scientists, envisaging the possibilities of these nanostructured silica shells as a general platform to obtain functional materials for several applications via chemical functionalization. Our first paper in the field was published in
ChemPlusChem ten years ago. Ten years later, in thisPerspective , we gather the most recent and relevant functional materials derived from diatom biosilica to show the growth and diversification that this field is currently experiencing, and the key role it will play in the near future. [ABSTRACT FROM AUTHOR]- Published
- 2024
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6. Effect of Diatomite on the Mechanical and Electrical Properties of Polyurethane/Epoxy Resin Composites.
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Li, Rui, Jiang, Ruihong, Tang, Qin, Yu, Jie, and Song, Dayu
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Epoxy resin is widely utilized for the encapsulation of power semiconductor devices, necessitating excellent insulation properties, mechanical performance, and moisture resistance. In this study, hexadecyltrimethoxysilane was employed to modify diatomite, which was then combined with polyurethane-modified epoxy resin to fabricate a series of filled composites with varying diatomite content. The influence of diatomite content on the mechanical properties, thermal properties, and insulation performance of the polyurethane/epoxy resin composites was investigated. Experimental results showed that, under the synergistic effect of polyurethane and diatomite, the composite containing 4 wt.% diatomite exhibited improvements of 13.95% and 61.11% in tensile strength and flexural strength, respectively, compared to the epoxy resin. The elongation at break and flexural displacement also increased by 22.46% and 68.23%, respectively. Furthermore, the incorporation of diatomite effectively compensated for the thermal losses caused by polyurethane, enhancing thermal stability. Electrical property tests indicated that the addition of diatomite reduced the dielectric constant and conductivity of the epoxy resin while simultaneously improving its breakdown strength. [ABSTRACT FROM AUTHOR]
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- 2024
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7. 硅藻土衍生硅碳负极材料的制备 及其储锂性能研究.
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张利锋, 王凯, 王晓飞, 刘毅, and 郭守武
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Two types of tubular and disc-shaped natural diatomite were used as the initial raw materials to prepare a series of diatomite derived silicon carbon anode materials. The crystal structure, microstructure, and chemical composition of the prepared products were systematically characterized using testing methods such as X-ray diffraction (XRD), Raman spectros-copy (Raman), scanning electron microscope (SEM), transmission electron microscope (TEM), and X-ray photoelectron spectroscopy (XPS), etc. The prepared diatomite derived silicon carbon anode materials were assembled as active substances to assemble lithium ion batteries. The effects of tubular and disc-shaped morphologies on its lithium storage performance were compared, and the effect of the amount of asphalt derived carbon coating on the specific capacity and cycling stability of the silicon carbon anode materials was investigated in detail. The test results show that both products tube DE-1 3 and tube DE-1: 6 have high capacity retention at a low current density of 0.2 Ag¹, after 500 cycles, the specific capacity -1 can be maintained at 443 mAh g¹ and 414 mAh g¹, respectively. While product tube DE-1: 6 has better structure stability at a higher current density of 0.5 Ag. [ABSTRACT FROM AUTHOR]
- Published
- 2024
8. Assessment of Physico-Chemical Behavior and Sorptivity—Diatomaceous Earth as Support for Paraffinic Phase-Change Materials.
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Przybek, Agnieszka
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HEAT storage , *DIATOMACEOUS earth , *THERMAL conductivity , *BEHAVIORAL assessment , *LIGHTWEIGHT materials - Abstract
Diatomite's most common application is its use as a sorbent for petroleum substances. Since paraffin is a petroleum derivative, this paper investigates the sorption capacity of diatomite to absorb it. In this paper, the physical and chemical properties were studied for 4 different fractions of diatomite (0–0.063 mm; 0–2 mm; 0.5–3 mm; and 2–5 mm) in the crude and calcined states, and the sorption capacity of diatomite earth for absorbing paraffinic phase-change substances was determined. The physical and chemical studies of the material included conducting an oxide chemical composition analysis using XRF, examining the composition of the mineral phases using X-ray diffraction, and determining the particle size, porosity, and thermal conductivity of the diatomite. Morphology images were also taken for all 8 diatomite variants using scanning electron microscopy. Each fraction was subjected to static calcination at 850 °C for 24 h. The results showed that the calcination of the diatomite increased the porosity of the material and reduced the thermal conductivity coefficient, and most importantly, the sorption capacity to absorb paraffins. The highest sorption capacity was characterized by calcined diatomite powder, that is, diatomite with the smallest particle size. Absorption of paraffinic substances by diatomite exceeding 200 wt.% is possible. Thus, diatomite is one of the feasible candidates for an economical and lightweight building material for making PCM composites for thermal energy storage in buildings. [ABSTRACT FROM AUTHOR]
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- 2024
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9. Efficient machine learning models for estimation of compressive strengths of zeolite and diatomite substituting concrete in sodium chloride solution.
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Ozcan, Giyasettin, Kocak, Burak, Gulbandilar, Eyyup, and Kocak, Yilmaz
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MACHINE learning , *BOOSTING algorithms , *MATERIALS science , *COMPRESSIVE strength , *RANDOM forest algorithms , *CONCRETE additives - Abstract
This study implements a set of machine learning algorithms to building material science, which predict the compressive strength of zeolite and diatomite substituting concrete mixes in sodium chloride solution. Particularly, Random Forest, Support Vector Machine, Extreme Gradient Boosting, Light Gradient Boosting, and Categorical Boosting algorithms are exploited and their optimal parameters are tuned. In the training and testing of these models, 28 day, 56 day, and 90 day compressive strength observations of 63 samples of 7 different concrete mixtures substituting Portland cement, zeolite, diatomite, zeolite + diatomite were used. Consequently, compressive strength experimentation results and machine learning predictions were compared through statistical methods such as RMSE, MAPE, and R2. Results denote that the prediction performance of machine learning is improving with tuned models. Particularly, RMSE, MAPE, R2 scores of Categorical Boosting are, respectively, 1.15, 1.45%, and 98.03% after parameter tuning design. The results denote that presented machine learning model can provide an advantage in the cost and duration of the compressive strength experiments. [ABSTRACT FROM AUTHOR]
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- 2024
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10. High-Temperature SHS Heat Insulators Based on Pre-Activated Mineral Raw Materials.
- Author
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Sadykov, Bakhtiyar, Khairullina, Ainur, Artykbayeva, Aida, Maten, Alua, Zhapekova, Anar, Osserov, Timur, and Bakkara, Ayagoz
- Abstract
In this paper, the results of the technological combustion of SHS heat insulators based on mineral origins are presented. It is shown that after mechanochemical treatment of minerals—diatomite—the kinetic characteristics of the combustion process change, providing targeted formation of the phase composition, structure, and properties of the SHS composite. A positive effect of using various modifiers during the MCT of diatomite—the activation of the combustion process—was established. The selection of modifiers provides an increase in the strength of the synthesized SHS composites as a result of the formation of aluminate compounds in the synthesis products, and a decrease in thermal conductivity to 0.157 W/m*K due to the formation of the ultraporous structure of the samples. [ABSTRACT FROM AUTHOR]
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- 2024
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11. C/Co 3 O 4 /Diatomite Composite for Microwave Absorption.
- Author
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Liao, Yan, Wang, Dashuang, Zhu, Wenrui, Du, Zhilan, Gong, Fanbo, Ping, Tuo, Rao, Jinsong, Zhang, Yuxin, and Liu, Xiaoying
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MAGNETIC flux leakage , *TRANSITION metal oxides , *IMPEDANCE matching , *DIELECTRIC loss , *ELECTRIC conductivity - Abstract
Transition metal oxides have been widely used in microwave-absorbing materials, but how to improve impedance matching is still an urgent problem. Therefore, we introduced urea as a polymer carbon source into a three-dimensional porous structure modified by Co3O4 nanoparticles and explored the influence of different heat treatment temperatures on the wave absorption properties of the composite. The nanomaterials, when calcined at a temperature of 450 °C, exhibited excellent microwave absorption capabilities. Specifically, at an optimized thickness of 9 mm, they achieved a minimum reflection loss (RLmin) of −97.3 dB, accompanied by an effective absorption bandwidth (EAB) of 9.83 GHz that comprehensively covered both the S and Ku frequency bands. On the other hand, with a thickness of 3 mm, the RLmin was recorded as −17.9 dB, with an EAB of 5.53 GHz. This excellent performance is attributed to the multi-facial polarization and multiple reflections induced by the magnetic loss capability of Co3O4 nanoparticles, the electrical conductivity of C, and the unique three-dimensional structure of diatomite. For the future development of bio-based microwave absorption, this work provides a methodology and strategy. [ABSTRACT FROM AUTHOR]
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- 2024
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12. The Influence of Diatomite on the Sound Absorption Ability of Composites.
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Łach, Michał, Gliścińska, Eulalia, Przybek, Agnieszka, and Smoroń, Krzysztof
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ABSORPTION of sound , *DIATOMACEOUS earth , *THERMOPLASTIC composites , *THERMAL conductivity , *ABSORPTION coefficients - Abstract
Diatomites are well-known mineral materials formed thousands of years ago from the skeletons of diatoms. They are found in many places around the world and have a wide range of applications. This article presents innovative research related to the possibility of using diatomite as a filler in composites to improve their sound absorption properties. The results of the study of the effect of diatomite processing (calcination) and its degree of fineness on the sound absorption coefficient of thermoplastic composites are presented. Three fractions of diatomite (0 ÷ 0.063 mm; 0.5 ÷ 3 mm; 2 ÷ 5 mm) and its variable mass proportion (0, 25, and 50 wt.%) were used. The composites were made with flax fibers as a reinforcement, polylactide as a matrix, and diatomite as an additional filler. This paper also presents the results of oxide chemical composition, diatomite mineral phase composition, morphology, and thermal conductivity coefficient of all diatomite fractions studied. In addition, the average particle size for diatomite powder was also determined. The most important of the studies was the determination of the acoustic properties of the aforementioned composites. As a result of the tests, it was found that the smallest fraction of diatomite particles and a variant without thermal treatment give the best effect in terms of sound absorption. [ABSTRACT FROM AUTHOR]
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- 2024
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13. Preparation of diatomite-based self-adhesive super-hydrophobic anti-corrosion coating.
- Author
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YANG Lei, CHEN Shibo, ZHANG Yanchi, LIU Shupei, ZHANG Xinfang, and RAO Jinsong
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Industrial production and daily life are inseparable from steel tools and equipment, but with the extension of the use of time, carbon steel equipment will inevitably occur corrosion, which will reduce the mechanical and physical properties of carbon steel, shorten the service life, waste economy at the same time may cause fire, explosion and other catastrophic accidents, so the corrosion of carbon steel is very important. So electrochemical method, organic coating method, corrosion inhibitor method and other common methods are designed to solve such problems. Among them, the organic coating method is the most convenient and the best effect, and among all kinds of coatings, the superhydrophobic coating has attracted the attention of researchers because of its unique surface structure and excellent anti-corrosion performance. However, the coating prepared by the existing method usually requires a large number of organic solvents, which is not only a complicated process, but also causes serious environmental pollution, and the later maintenance work is very complicated. Therefore, it is necessary to prepare a self-adhesive and self-cleaning coating which is not limited by time, space and thermal spraying equipment for the protection of carbon steel equipment. In this study, a preparation method was introduced. The anti-corrosion coating with self-adhesion, self-adsorption and long-term superhydrophobic properties was prepared by scraping coating through secondary hydrothermal method, and relevant tests were carried out on it. The results show that the modified composite coating has a maximum hydrophobic Angle of 151.52° and an impedance modulus of 1011 Ω • cm², showing excellent self-cleaning and anti-corrosion properties. [ABSTRACT FROM AUTHOR]
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- 2024
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14. Thermal Insulation Properties of Ceramovermiculite and Ceramoperlite Materials Containing a Wollastonite Binder at High Temperature.
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Rodin, A. I., Ermakov, A. A., Korotaev, S. A., Kyashkin, V. M., and Rodina, N. G.
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FIREPROOFING agents , *THERMOPHYSICAL properties , *INSULATING materials , *INDUSTRIAL wastes , *PERLITE - Abstract
High-temperature insulation materials are used extensively in civil engineering as flame retardant materials, as well as in numerous industrial sectors. The raw materials used in the production of these materials include rocks and industrial waste. The article substantiates the feasibility of using ceramovermiculite and ceramoperlite materials containing a wollastonite binder as high-temperature insulation. The materials were obtained through the firing of a charge containing chalk, diatomite, and a heat-resistant filler (expanded perlite or expanded vermiculite). The material of the fired samples with expanded vermiculite is primarily composed of the crystalline phase of wollastonite and biotite, with a minor amount of quartz and akermanite-gehlenite. The use of expanded perlite as a heat-resistant filler results in the presence of a low amount of plagioclases in addition to the crystalline phase of wollastonite in fired samples, along with an amorphous phase. The physicomechanical properties of the charge and the fired samples were determined, and the effect of the apparent density and phase composition of the developed materials on the variation in their thermal insulation properties at high temperatures was studied. The thermal insulation properties of the materials were determined by supplying heat flow from the heating chamber of the muffle furnace to one side of the sample. The samples from the developed materials exhibited apparent densities ranging from 375 to 630 kg/m3 and compressive strengths between 0.95 and 3.25 MPa. The developed ceramoperlite materials containing wollastonite binder can be used as high-temperature thermal insulation up to +900°C, while ceramovermiculite can be used up to +1050°C. According to a range of physicomechanical and thermophysical properties, the materials obtained are comparable to or exceed the performance of known analogs. [ABSTRACT FROM AUTHOR]
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- 2024
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15. One-step construction of halogen-free, phosphorus-free, mono-component and Mn-doped diatomite for effectively improving the fire safety of silicone rubber.
- Author
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Su, Xinying, Chai, Weihong, Zhang, Ziyang, Tang, Zhenlin, Gao, Meihuan, Li, Yingge, Han, Zhishuang, and Zheng, Zaihang
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FIREPROOFING , *HEAT release rates , *FIRE prevention , *SILICONE rubber , *CHEMICAL processes , *FIRE resistant polymers , *FIREPROOFING agents - Abstract
Aiming at settling the critical problems of ecological and environmental safety caused by traditional halogen-containing and phosphorus-containing flame-retardant system, this paper has fabricated a transition metal manganese ion (Mn2+) loaded diatomite (Mn@DE) via a simple chemical modification process, which can be employed as raising the flame retardancy of silicone rubber (SR). Compared with traditional flame retardants, the unique lamellar shielding ability and Mn-enhanced catalytic charring ability from designed mineral-based flame retardants are conductive to upgrading the flame-retardant level of silicone rubber/Mn-modified diatomite (SR/Mn@DE) composites. The results demonstrate that when the amount of Mn@DE reaches 30 phr in the composites, the limiting oxygen index (LOI) and vertical combustion tests of SR/30 phr Mn@DE can reach 27.3% and UL-94 V-0 ratings, respectively. Simultaneously, the reduction for peak heat release rate (PHRR) and total heat rate (THR) of SR/Mn@DE can achieve 55.3% and 66.1%, revealing that the fire hazard of SR has been effectively decreased. Thermogravimetric analysis (TGA) has enlightened that the introduction of Mn onto diatomite can effectively reinforce the thermal stability and char-forming ability of SR composites. Through the systematic analysis for combustion residues, the condensed flame-retardant mechanism of SR/Mn@DE via restraining the heat transfer and fuel feedback can be primarily inferred. Therefore, this paper have provided a fast and practical flame-retardant strategy in order to discarding the halogen-/phosphorus-containing flame retardants, which will open up the key problem of limited application for SR composites in more fields. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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16. Degradation of biomass tar catalyzed by Fe/Ce supported on diatomite-based foam ceramics.
- Author
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Yang, Chen, Pang, Yunji, Li, GangHui, Chen, Yisheng, and Li, Huan
- Abstract
Foam ceramics with excellent pore structure were prepared by using mineral diatomite with abundant reserves. It is used for catalytic reforming of biomass pyrolysis gas. Fe
2 O3 and CeCl3 were loaded on foam ceramics as active materials to explore the effect of using them as catalyst supports. The experimental results show that diatomite-based foam ceramics (DBFC) have good catalytic performance. At 750 ℃, the gas yield was increased by 6.5% and the liquid yield was reduced by 16.04% under the catalysis of diatomite-based foam ceramics. After repeated use tests, the results show that the anti-deactivation activity is higher, and the catalytic effect of the second use is better than that of the third use, but still better than that of the first use. When DBFC is used as catalyst carrier, Fe2 O3 loaded on it has better catalytic performance. At 750 ℃, the gas yield increased by 13.14% and the liquid yield decreased by 33.54%. The analysis of gas phase products shows that the use of DBFC will increase H2 , CH4 , and CO2 in the syngas, but will reduce the yield of CO, and the increase of CO2 yield is greater than that of H2 and CH4 . Fe2 O3 loading leads to the highest gas productivity, but the proportion of CO2 in syngas is also the highest and LHV is the lowest. [ABSTRACT FROM AUTHOR]- Published
- 2024
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17. Fabrication and characterization of graphene oxide and reduced graphene oxide decorated diatomite composite materials and their adsorption performance for uranium ions.
- Author
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Yusan, Sabriye, Mumcu, Burak, López-Maldonado, Eduardo A., EL Kaim Billah, Rachid, and Bahsis, Lahoucine
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ENDOTHERMIC reactions ,DIATOMACEOUS earth ,EXOTHERMIC reactions ,GRAPHENE oxide ,URANIUM oxides ,URANIUM - Abstract
In this study, the composite materials based on the incorporation of diatomite of graphene oxide (GO)/reduced graphene oxide (rGO/diatomite) were developed and characterized by different techniques (SEM, XRD, FTIR and BET). Developed composites were used for the first time in the removal of uranium ions from aqueous solutions. In adsorption studies, parameters affecting the adsorption efficiency such as solution pH, temperature, contact time and initial U(VI) concentration were investigated using full factorial experimental design (FFED). ANOVA (analysis of variance) analysis within the 95 % confidence interval of the model applied to control the compatibility of the model and the experimental findings was examined. Langmuir, Freundlich and Temkin isotherms were used to determine the adsorption model and related parameters were calculated. In addition, adsorption thermodynamic parameters such as enthalpy, Gibbs free energy change and entropy were calculated. The uranium removal behaviour on GO/diatomite and rGO/diatomite was better characterized by the pseudo-second order and Langmuir models, indicating that uranium ions were chemically adsorbed onto composite materials. Additionally, it was observed that higher temperatures promoted the uranium removal on GO/diatomite and rGO/diatomite, suggesting that the removal process was a spontaneous endothermic and exothermic reaction, respectively. In addition, the adsorption of U(VI) with GO/diatomite and rGO/diatomite was investigated using density functional theory (DFT) study. Configuration and adsorption energy were determined. The GO/diatomite composite materials can be a promising candidate as an adsorbent for the removal of uranium from aqueous solutions. [ABSTRACT FROM AUTHOR]
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- 2024
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18. Diatomite-incorporated hierarchical scaffolds for osteochondral regeneration
- Author
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Cuijun Deng, Chen Qin, Zhenguang Li, Laiya Lu, Yifan Tong, Jiaqi Yuan, Feng Yin, Yu Cheng, and Chengtie Wu
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Diatomite ,Si release ,Hierarchical scaffolds ,3D printing ,Osteochondral regeneration ,Materials of engineering and construction. Mechanics of materials ,TA401-492 ,Biology (General) ,QH301-705.5 - Abstract
Osteochondral regeneration involves the highly challenging and complex reconstruction of cartilage and subchondral bone. Silicon (Si) ions play a crucial role in bone development. Current research on Si ions mainly focuses on bone repair, by using silicate bioceramics with complex ion compositions. However, it is unclear whether the Si ions have important effect on cartilage regeneration. Developing a scaffold that solely releases Si ions to simultaneously promote subchondral bone repair and stimulate cartilage regeneration is critically important. Diatomite (DE) is a natural diatomaceous sediment that can stably release Si ions, known for its abundant availability, low cost, and environmental friendliness. Herein, a hierarchical osteochondral repair scaffold is uniquely designed by incorporating gradient DE into GelMA hydrogel. The adding DE microparticles provides a specific Si source for controlled Si ions release, which not only promotes osteogenic differentiation of rBMSCs (rabbit bone marrow mesenchymal stem cells) but also enhances proliferation and maturation of chondrocytes. Moreover, DE-incorporated hierarchical scaffolds significantly promoted the regeneration of cartilage and subchondral bone. The study suggests the significant role of Si ions in promoting cartilage regeneration and solidifies their foundational role in enhancing bone repair. Furthermore, it offers an economic and eco-friendly strategy for developing high value-added osteochondral regenerative bioscaffolds from low-value ocean natural materials.
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- 2024
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19. Preparation of Fe-Modified Diatomite-Based Ceramsite for Efficient Phosphate Adsorption: Utilizing Diatomite's Distinctive Porous Structure and Surface Silanol Groups.
- Author
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Chen, Zhichao, Min, Yulin, Zhao, Xin, Shi, Penghui, and Lu, Hongxiu
- Subjects
PRECIPITATION (Chemistry) ,DIATOMACEOUS earth ,LANGMUIR isotherms ,ZETA potential ,ADSORPTION capacity - Abstract
Ceramsites are extensively employed as substrates for adsorbents in studies focused on phosphorus adsorption, leaving ceramsites crafted from diatomite less explored. Diatomite-based ceramsite, with its distinct porous architecture and surface silanol functionalities, is adept at supporting a variety of metal oxides, presenting a distinct advantage over other ceramsite variants. In light of this, the present study embarked on producing diatomite-based ceramsite using diatomite as the foundational material, subsequently enhancing it through the incorporation of Fe, thus yielding an Fe-modified diatomite-based ceramsite. Through adsorption testing, the modified ceramsite demonstrated a significantly improved adsorption capacity of 4.06 mg P/g, marking a substantial enhancement from the initial capacity of 0.9 mg P/g. The process of phosphorus adsorption exhibited a strong alignment with the Langmuir isotherm model and the pseudo-second-order kinetic model. In-depth analyses employing XRD, FTIR, zeta potential, and XPS techniques have revealed that the principal mechanisms driving the adsorption process are centered on interactions involving electrostatic forces, the formation of chemical precipitates, and the exchange of ligands. This investigation not only opens new avenues for the application of diatomite-based ceramsite but also lays down a theoretical foundation for its modification, thereby enriching the spectrum of its utility. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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20. The effects of the contents of modified‐diatomite on the properties of modified‐diatomite/epoxy resin composites.
- Author
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Wang, Huixiao, Lou, Chunhua, Yu, Jingjing, and Yang, Yuxin
- Subjects
EPOXY resins ,GLASS transition temperature ,DIFFERENTIAL scanning calorimetry ,IMPACT strength ,DIATOMACEOUS earth ,BENDING strength - Abstract
External plasticization is one of the effective ways to toughen epoxy resins. In this study, an inorganic filler (EMD) was prepared by chemical modification of diatomite and was used to fill epoxy resin matrix. The effects of different amounts (5%, 10%, 15%, and 20%) of raw diatomite (RD) and modified‐diatomite (EMD) on the mechanical and thermal properties of epoxy resin composites were studied. The mechanical results showed that the impact strength, tensile strength, and bending strength of EMD/EP were higher than those of RD/EP. The impact strength of EMD‐15/EP reached 5.39 KJ/m2, which was 36.8% higher than that of RD‐15/EP. Thermogravimetric analysis showed that the thermal stability of EMD/EP was better than that of RD/EP. The results of DMA show that the glass transition temperature of EMD/EP was lower than that of RD/EP. Non‐isothermal differential scanning calorimetry study showed that the apparent activation energy of EMD‐15/EP was much lower than that of RD‐15/EP, which proved that EMD could promote the curing of epoxy resin. The Malek method was used to determine that both the RD‐15/EP and EMD‐15/EP curing systems were autocatalytic (Šesták–Berggren) models. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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21. The Diatomite Grinding Technology Concept for the Protection of Diatomite Shells and the Control of Product Grading.
- Author
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Stempkowska, Agata, Gawenda, Tomasz, and Smoroń, Krzysztof
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DIATOMACEOUS earth , *SCANNING electron microscopes , *PARTICLE analysis , *X-ray diffraction , *BALL mills - Abstract
Diatomite deposits in Poland are located in the Podkarpackie Voivodeship, and the only active deposit is in Jawornik Ruski. Therefore, it is a unique material. Improved rock processing methods are constantly in demand. In the research presented here, we have used research methods such as X-ray diffraction (XRD), scanning electron microscope (SEM), particle shape analysis, and appropriate sets of crushing machines. Diatomite comminution tests were carried out on test stands in different crushers (jaw crusher, hammer crusher, high-pressure roller press, ball mill) using different elementary crushing force actions: crushing, abrasion, and impact, occurring separately or in combination. The machines were tested with selected variable parameters to obtain products with a wide range of grain sizes ranging from 0 to 10 mm. The ball mill (yield 87%, system C3) and the hammer crusher with HPGR (high-pressure grinding roller) (yield 79%, system D2 + D3) have the greatest impact on diatom shell release and accumulation in the finest 0–5 μm and 5–10 μm fractions. For commercial purposes, it is important to obtain very fine fractions while keeping the shells undisturbed. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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22. Utilisation of Biosilica as Active Silica Source for Metakaolin-Based Geopolymers.
- Author
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Guo, Haozhe, Huang, Zhihao, Pantongsuk, Thammaros, Yu, Ting, Zhang, Baifa, Luo, Jinghan, and Yuan, Peng
- Subjects
- *
DIATOMACEOUS earth , *DIATOM frustules , *SILICA , *DIATOMS , *SOLUBLE glass - Abstract
This study explores the potential of biosilica including diatom and diatomaceous earth as alternative silica sources for metakaolin-based geopolymers. Diatomaceous earth, composed of fossilised diatom frustules rich in amorphous silica, and diatoms, a sustainable source of renewable biosilica, are investigated for their effectiveness in enhancing geopolymer properties. Through detailed analyses including FTIR, XRD, and SEM, the study evaluates the impact of these biosilica sources on geopolymer compressive strength and microstructure, comparing them with conventional sodium silicate. Results show that diatoms exhibit significant promise, achieving 28-day strength up to 17.9 MPa at a 30% mass fraction, while diatomaceous earth reaches 26.2 MPa at a 50% addition rate, demonstrating their potential as active silica sources. Furthermore, the study elucidates the role of organic matter in biosilica on geopolymerisation, highlighting its influence on active silica release and the strength performance of products. This study proposes a novel pathway to enhance the sustainability of geopolymers through the utilisation of biosilica from diatoms, contributing to advancements in eco-efficient construction materials. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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23. Towards Safe Diatomite Sludge Management: Lead Immobilisation via Geopolymerisation.
- Author
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Guo, Haozhe, Huang, Zhihao, Zhang, Baifa, Yu, Ting, Pantongsuk, Thammaros, and Yuan, Peng
- Subjects
- *
FOURIER transform infrared spectroscopy techniques , *LEAD , *SLUDGE management , *MINES & mineral resources , *DIATOMACEOUS earth , *KAOLIN - Abstract
Diatomite, a natural adsorbent rich in active silica, serves as a valuable precursor for geopolymer synthesis. The safe disposal of diatomite as a failed lead (Pb(II)) adsorbent is critical to prevent secondary contamination. This study investigated the immobilisation efficiency of geopolymerisation for Pb(II)-rich diatomite sludge. Low-grade diatomite with high ignition loss was utilised in the synthesis of alkali-activated geopolymers. It was demonstrated that the geopolymers achieved a compressive strength of 28.3 MPa with a 50% replacement rate of metakaolin by diatomite sludge, which was not a compromise in strength compared to that of the geopolymer with no Pb(II) (26.2 MPa). The leaching behaviour of Pb(II) was evaluated using water and acetic acid, yielding concentrations below 3 mg/L and immobilisation efficiencies of 95% in both scenarios. Analytical techniques including Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) elucidated the mineral composition and chemical environment of the geopolymers. These analyses revealed that Pb(II) migrated from diatomite pores, potentially forming soluble hydroxides under sufficient hydroxide, which then participated in condensation with silicon and aluminium monomers, effectively immobilising Pb(II) within amorphous aluminosilicate gels. Furthermore, the formation of the amorphous gels within diatomite pores hindered Pb(II) leaching, encapsulating Pb(II) effectively. This study presents a novel approach to immobilising heavy metals within building materials, enhancing mineral resource utilisation efficiency while addressing environmental contamination concerns. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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24. Enhanced photocatalytic degradation of rhodamine B dye and antibacterial activity of diatomite-supported TiO2/ZnS hybrid catalyst via additional calcination.
- Author
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Benzelmat, Lamia Ahlem, Bernaoui, Cheikh Reda, Hadjel, Mohammed, Djediai, Houria, Cherrak, Rachida, Goual, Nor El Houda, Alaoui, Chakib, Karkachi, Noureddine, Benhamed, Amine, and Taibi, Zohra
- Abstract
The current investigation introduces a novel diatomite-TiO
2 /ZnS photocatalyst tailored to address the challenges posed by organic dye pollution while concurrently providing antibacterial activity. The methodology commences with diatomite purification, followed by the deposition of nanoparticles forming a heterojunction system between ZnS and TiO2 on the diatomite surface, culminating in the development of the nanocomposite. Notably, the optical absorption edge of the diatomite-TiO2 /ZnS nanocomposite resides within the UV light spectrum. Subsequent heat treatment at 500 °C heightens the system's responsiveness to UV radiation. The nanocomposite exhibits exceptional efficacy in the photocatalytic degradation of rhodamine B dye. The optimal catalyst, DTZS 500, achieves a remarkable 98% degradation of rhodamine B within 180 min, boasting a pseudo-first-order constant of 0.03299 min−1 , which is twice that of P25. Furthermore, nearly complete mineralization of organic matter is evidenced by chemical oxygen demand (COD) measurements. These superior performances are ascribed to the well-dispersed TiO2 and ZnS on the diatomite surface, the adsorption properties of diatomite, and the effective separation of photo-generated electron–hole pairs facilitated by the formation of a heterojunction system between TiO2 and ZnS. Moreover, the nanocomposite exhibits notable antibacterial effects against S. aureus, as evidenced by substantial inhibition zones measuring 38 mm in diameter. This study thus presents a promising avenue towards the provision of highly efficient and economical solutions for water treatment, encompassing both photocatalysis and bacterial disinfection. [ABSTRACT FROM AUTHOR]- Published
- 2024
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25. Analysis of the Influence of Borate and Fluoride Fluxes on the Sintering of Silicate Raw Materials.
- Author
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Gol'tsman, B. M., Yatsenko, E. A., Bostanov, Yu. A., Panteleeva, A. E., Smoliy, V. A., and Yatsenko, V. S.
- Subjects
- *
HEAT treatment , *HEAT flux , *DIATOMACEOUS earth , *RAW materials , *BORAX - Abstract
The effectiveness of using borate (borax) and fluoride (sodium fluoride) fluxes in the sintering of crystalline (sand) and amorphous (diatomite) silicate raw materials was considered. The change in the density and appearance of samples with varying amounts of fluxes during their heat treatment at different temperatures was described. It was shown that the introduction of 4 wt.% of borax reduces the temperature necessary to reach a density of 1500 kg/m3 by 100°C, and 6 wt.% of borax by 200°C. It was shown that the introduction of fluxes increases the amount of x-ray amorphous glass phase due to depolymerization of the silicon-oxygen network and the formation of a low-temperature melt. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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26. 碳热还原氮化硅藻土制备 Si2N2O/SiC 复合粉体.
- Author
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万 赣, 匡 猛, 黄思源, 张琎珺, 王 平, and 张声洲
- Abstract
Copyright of Bulletin of the Chinese Ceramic Society is the property of Bulletin of the Chinese Ceramic Society Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
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- 2024
27. Durable and High-Temperature-Resistant Superhydrophobic Diatomite Coatings for Cooling Applications.
- Author
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Pereira, José, Souza, Reinaldo, Moreira, António, and Moita, Ana
- Subjects
CONTACT angle ,FOURIER transform infrared spectroscopy ,SUPERHYDROPHOBIC surfaces ,SILANIZATION ,SUBSTRATES (Materials science) - Abstract
The present work is aimed at the development of superhydrophobic coatings and surfaces with enhanced robustness and boiling temperature resistance. We will address the synthesis method of the coatings, which was based on the preparation of a composite of silanized diatomite particles embedded in epoxy resin. After the synthesis of the composite solution, it was applied by dip-coating in stainless steel substrates and submitted to a post-treatment cure in an oven. The method proved to be a comparatively fast and simple one. Then, the substrate/coating sets were characterized using different techniques, including Fourier transform infrared spectroscopy and scanning electron microscopy, and their water contact angle and roughness were measured. Apart from this, the physical and chemical robustness of the sets was also tested using diverse resistance tests like adhesion strength, abrasion resistance, resistance to strong acids and bases, and resistance to boiling water. The main results are that we obtained robust coatings, with wettability defined by water contact angles above 150°. Also, the synthesized coatings revealed good resistance to boiling water, as their properties were almost unchanged after the completion of a long period of tests. The characterization of the produced coatings suggested their propensity to be explored for use in water boiling surfaces and interfaces for cooling purposes in boiling heat transfer systems. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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- View/download PDF
28. Improving Sag Resistance in Geopolymer Coatings Using Diatomite Filler: Effects on Rheological Properties and Early Hydration.
- Author
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Hu, Yuan, Jin, Zuquan, Pang, Bo, Du, Zhantao, Li, Xiangxiang, and Huang, Yuxin
- Subjects
- *
RHEOLOGY , *DIATOMACEOUS earth , *STRESS concentration , *YIELD stress , *SURFACE coatings , *POLYMER colloids , *KAOLIN , *POLYMER clay - Abstract
The reduction in the rheological parameters and dissolution rate of precursors in geopolymer coatings during early hydration significantly contributes to sagging. This study aims to improve the sag resistance of these coatings by incorporating diatomite filler. Rheological testing was conducted to assess the impact of diatomite and its concentration on the yield stress, plastic viscosity, and thixotropy of the geopolymer coatings. The results indicated that diatomite's large specific surface area and high reactivity have a significant influence on the rheological parameters and early dissolution rate of precursors. With a diatomite concentration of 1.1%, the coating exhibited a yield stress of 2.749 Pa and a plastic viscosity of 0.921 Pa·s, maintaining stability, homogeneity, and no sagging at a thickness of 600 μm. Furthermore, the highly active SiO2 in diatomite participates in the secondary hydration reaction of the geopolymer materials led to the formation of substantial C-(A)-S-H gel. This gel enhances internal interconnectivity within the coating, thereby improving its rheological and mechanical properties. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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29. The Influence of Environmental Factors on the Degradation of PLA/Diatomaceous Earth Composites.
- Author
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Dobrosielska, Marta, Dobrucka, Renata, Brząkalski, Dariusz, Pajewska-Szmyt, Martyna, Kurzydłowski, Krzysztof J., and Przekop, Robert E.
- Subjects
- *
DIATOMACEOUS earth , *ENVIRONMENTAL degradation , *RHEOLOGY , *ULTRAVIOLET radiation , *BEESWAX , *POLYAMIDES , *MINERAL dusts - Abstract
In the present study, tests were carried out on composite samples on a polylactide matrix containing 25% by weight of mineral filler in the form of diatomaceous earth, base, and silanized with GPTMOS (3-glycidoxypropyltrimethoxysilane), OTES (n-octyltriethoxysilane), and MTMOS (methyltrimethoxysilane) silanes. The addition of two types of waxes, synthetic polyamide wax and natural beeswax, were used as a factor to increase the rheological properties of the composites. The obtained samples were characterized in terms of the effect of filler silanization on the degradation rate of the composites. The tests were conducted under different conditioning conditions, i.e., after exposure to strong UV radiation for 250 and 500 h, and under natural sunlight for 21 days. The conditioning carried out under natural conditions showed that the modified samples exhibit up to twice the degradation rate of pure polylactide. The addition of synthetic wax to the composites increases the tendency to agglomerate diatomaceous earth, while natural wax has a positive effect on filler dispersion. For composites modified with GPTMOS and OTES silanes, it was noted that the addition of natural wax inhibited the degree of surface degradation, compared to the addition of synthetic wax, while the addition of MTMOS silane caused the opposite effect and samples with natural wax degraded more strongly. It was shown that, despite the high degree of surface degradation, the process does not occur significantly deep into the composite and stops at a certain depth. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
30. Multifunctional Anatase–Silica Photocatalytic Material for Cements and Concretes.
- Author
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Strokova, Valeria, Ogurtsova, Yulia, Gubareva, Ekaterina, Nerovnaya, Sofya, and Antonenko, Marina
- Subjects
MORTAR ,TITANIUM dioxide surfaces ,CONCRETE ,PORTLAND cement ,CEMENT ,DIATOMACEOUS earth ,CEMENT admixtures ,CONCRETE additives - Abstract
The purpose of this research was to study the influence of multifunctional anatase–silica photocatalytic materials (ASPMs) with various photocatalytic and pozzolanic activities on the properties of white portland cement and fine-grained concrete. ASPMs were synthesized by a sol–gel method, during which the levels of photocatalytic and pozzolanic activity were regulated by a certain amount of solvent. ASPMb, obtained with the use of a smaller amount of solvent, was characterized by increased pozzolanic activity due to the lower degree of coating of the surface of diatomite particles with titanium dioxide and the higher content of an opal–cristobalite–tridymite-phase and Bronsted acid sites. They promoted the reaction of diatomite with portlandite of cement stone and allowed significant decreases in the strength of cement–sand mortar to be avoided when replacing 15% of the cement with ASPMs. This allowed self-cleaning fine-grained concrete to be produced, which, after forced carbonization, simulating the natural aging of the product during operation, retained the ability of self-cleaning without changes. ASPMc, produced with the use of a larger amount of solvent with a more uniform distribution of titanium dioxide on the surface of diatomite, allowed fine-grained concrete with a high self-cleaning ability to be obtained, but with a lesser manifestation of the pozzolanic effect. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
31. Producing a siliceous ferroalloy from a mixture of amorphous rocks
- Author
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V.M. Shevko, N.M. Mirkayev, D.K. Aitkulov, and A.D. Badikova
- Subjects
Tripoli ,Diatomite ,Opoka ,Electric smelting ,Planning of experiments ,Optimization ,Technology - Abstract
The main silicon-containing component in a charge during ferrosilicon smelting is quartzite. The carbothermic reduction rate of the crystalline structure SiO2 has a limitation associated with a fixed energy reserve of silicon-oxygen bond. The reactive capacity of silica can be increased by using its amorphous form instead of the crystalline SiO2. The amorphous form of silica has a higher dispersion, greater free surface energy, and, consequently, a more active degree of entering into a reaction. Such silica-containing materials include amorphous rocks: diatomite, opoka, tripoli. The article presents the results of experimental studies of electrothermal ferrosilicon production from a mixture of amorphous rocks (tripoli, opoka, diatomite with a mass ratio of 1:1:1).It is established that when smelting the mixture of amorphous rocks containing 77 % SiO2, 7.9 % Al2O3, 5.2 % Σ CaO and MgO, 4 % Σ K2O Na2O, 3.3 % Fe2O3, 1.3 % CaCO3, 0.9 % CaSO4, 0.4 % others, three ferrosilicon grades are formed: FeSi25 (22–29 % Si), FeSi45 (41–47 % Si), FeSi50 (47–52 % Si) with the extraction degree of 70–87.6 % silicon into the alloy. Moreover, the ferrosilicon grade decreases with an increase in steel shavings in the charge from 21.9-31.4 % to 33–35 %. In comparison with ferrosilicon smelting from a standard charge containing quartzite with the crystalline form of SiO2, steel shavings and coke, ferrosilicon production from the mixture of amorphous rocks allows to increase the process rate by 17.5–21.6 %. It is possible to increase the silicon extraction degree into the alloy from 80-85 %–94.5 % if its final stage is carried out in the resistance mode. Widespread occurrence in nature, favorable conditions of occurrence, low cost, high reactive capacity are favorable factors for using amorphous rocks in the production of ferroalloys.
- Published
- 2024
- Full Text
- View/download PDF
32. Pilot-scale evaluation of a dynamic body-feed filtration system for primary clarification of snake antivenoms produced by the caprylic acid method
- Author
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Andrés Sánchez, Maykel Cerdas, Jairo Gutiérrez, Mariángela Vargas, Álvaro Segura, María Herrera, Stephanie Chaves-Araya, Ronald Sánchez, Mauren Villalta, Gina Durán, Adriana Sánchez, Gabriela Solano, Daniel Cordero, Paola Sánchez, José María Gutiérrez, and Guillermo León
- Subjects
Caprylic acid ,Diatomite ,Dynamic body-feed filtration ,Equine plasma ,Snake antivenom ,Toxicology. Poisons ,RA1190-1270 - Abstract
The performance of dynamic body-feed filtration (DBF) in the removal of bulky solids produced during the manufacturing of snake antivenoms using the caprylic acid method was evaluated. For this purpose, diatomites with different filterability properties were compared in a bench-scale study to assess their effectiveness in removing the precipitated material formed after the addition of caprylic acid to equine hyperimmune plasma. C1000 diatomite at a concentration of 90 g/L of precipitated plasma showed the best performance. Then, the process was scaled up to three batches of 50 L of hyperimmune horse plasma. At this pilot scale, 108 ± 4% of the immunoglobulins present following plasma precipitation were recovered after DBF. The antivenoms generated using this procedure met quality specifications. When compared to open filtration systems commonly used at an industrial scale by many antivenom manufacturers, DBF has a similar yield and produces filtrates with comparable physicochemical characteristics. However, DBF ensures the microbiological quality of the primary clarification in a way that open systems cannot. This is because: 1) DBF is performed in a single-use closed device of depth filters which prevents microbial contamination, and 2) DBF removes bulky material in few minutes instead of the more than 24 h needed by open filtration systems, thus reducing the risk of contamination. It was concluded that DBF is a cost-effective, easily validated, and GMP-compliant alternative for primary clarification following caprylic acid precipitation of plasma in snake antivenom production.
- Published
- 2024
- Full Text
- View/download PDF
33. Magnesia Cements Based on Trepel and Diatomite of the Vladimir Region
- Author
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Kapush, Ilya, Bitkov, Vladislav, Bulakhtin, Sergey, Semenov, Aleksandr, Zakrevskaya, Lubov, di Prisco, Marco, Series Editor, Chen, Sheng-Hong, Series Editor, Vayas, Ioannis, Series Editor, Kumar Shukla, Sanjay, Series Editor, Sharma, Anuj, Series Editor, Kumar, Nagesh, Series Editor, Wang, Chien Ming, Series Editor, Vatin, Nikolai, editor, Roshchina, Svetlana, editor, and Serdjuks, Dmitrijs, editor
- Published
- 2024
- Full Text
- View/download PDF
34. Green based composite polyurethane coatings for steel
- Author
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Konovalov, Dmitry S., Saprykina, Natalia N., and Zuev, Vjacheslav V.
- Published
- 2024
- Full Text
- View/download PDF
35. Fabrication of polyvinyl alcohol-diatomite hybrid aerogel and its application for treatment of tritium-containing waste oil
- Author
-
Chen, Shi and Li, Yuan-yuan
- Published
- 2024
- Full Text
- View/download PDF
36. Evaluating the antibiotic adsorption ability of diatomite minerals: the role of treatment agents
- Author
-
Nguyen, The Luan, Le Phan, Quynh Nhu, Vo, Oanh Kieu Thi, Le, Tien Khoa, and Pham, Van Viet
- Published
- 2024
- Full Text
- View/download PDF
37. Physico-mechanical properties of geopolymers prepared with the partial incorporation of ceramic wastes
- Author
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T. P. P. Coelho, B. P. Bezerra, J. R. Verza, A. P. Luz, and M. R. Morelli
- Subjects
geopolymers ,metakaolin ,diatomite ,solid wastes ,properties ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
Abstract The utilization of waste or by-products in geopolymers is an effective strategy that contributes to the development of more sustainable ceramics. The present study aimed to evaluate the physico-mechanical properties of compositions prepared by partially replacing aluminosilicate precursors (metakaolin or calcined diatomite) with solid wastes (granite, roof tile chamotte, or glass powder) at contents of 10, 20, and 40 wt%. Geopolymers were synthesized by blending the solid raw materials (precursor+wastes) with an alkaline activating solution comprising NaOH and colloidal silica suspension. The samples were cured at 40 °C for 24 h, and the following analyses were conducted: elastic modulus, compressive strength, porosity, density, X-ray diffraction, and Fourier-transform infrared spectroscopy measurements. The results demonstrated that the formulation containing 10 wt% of chamotte exhibited the best performance, showing a remarkable mechanical strength of 31.7 MPa after one day of curing. Therefore, by incorporating waste materials into geopolymers, not only can the environmental impact be minimized, but it also presents an opportunity to utilize resources that would otherwise go to waste.
- Published
- 2024
- Full Text
- View/download PDF
38. Diatomite with gold nanoparticles for atrazine adsorption
- Author
-
Melany Aguilar, Sarah Briceño, Karla Vizuete, Alexis Debut, Carlos Reinoso, and Gema González
- Subjects
Diatomite ,Nanoparticles ,Atrazine ,Pesticide ,Removal ,SERS ,Chemistry ,QD1-999 - Abstract
Atrazine is a commonly used herbicide worldwide, and it has significant environmental concerns due to its toxic ecological effects. This work uses diatomite decorated with gold nanoparticles to evaluate its capacity for atrazine adsorption. The structural characterization was studied by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Energy Dispersive spectroscopy (EDX), Fluorescence microscopy and X-ray photoelectron spectroscopy (XPS). Our findings reveal that diatomite decorated with gold nanoparticles with an average particle size of 10 nm enhances the Raman signal and fluorescence intensity for atrazine detection. Experimental conditions, such as atrazine concentration, pH, contact time, and diatomite mass, have been optimized to quantify the maximum removal conditions using ultraviolet–visible spectroscopy, reaching a maximum adsorption of 2.5 mg/g in 4 h. FTIR and XPS evidence the interaction of the amine groups of the atrazine with the diatomite-decorated surface. The impact of this work relies on environmental remediation using naturally available diatomite decorated with gold nanoparticles and understanding the binding interactions for the removal of atrazine.
- Published
- 2024
- Full Text
- View/download PDF
39. Preparation and adsorption kinetics and thermodynamics of sodium humate‐modified diatomite.
- Author
-
Chen, Hongye, Gao, Ruqin, and Ma, Qiuhui
- Subjects
- *
ADSORPTION kinetics , *DIATOMACEOUS earth , *THERMODYNAMICS , *FIELD emission electron microscopy , *TRANSMISSION electron microscopes - Abstract
Diatomaceous earth has been used as a nonorganic carrier to prepare a sodium humate modified diatomaceous space using the sol‐gel method. X‐ray diffraction, field emission scanning electron microscopy, transmission electron microscope, the Brunauer–Emmett–Teller (BET) method, and other methods were used to characterize its physio‐chemical properties. The effects of sodium humate/diatomite on the pH of tetracycline in water, the dosage of adsorbent, and pollutant temperature on the adsorption effect were studied. The results show that after alkali modification, the porous structure of diatomite remains undamaged, and the specific surface area of the modified sample is increased to 12.712 m2/g, and the average pore diameter is reduced to 146.19 nm. Adding 20‐mg sodium humate/diatomite into 100‐mL tetracycline wastewater with an initial concentration of 20 mg/L, and pH of 5 at a temperature of 55°C, the adsorption capacity reaches 75.1 mg/L, and the removal rate reaches 78.3%. The quasi‐second‐order kinetic model was fitted by regression and found to have R2 > 0.99, indicating that the adsorption process was one of surface adsorption. It is a process that involves initially rapid adsorption and then slowly reaching equilibrium. As an adsorption thermodynamics model, the Temkin, Redlich‐Peterson and Koble‐Corrigan models can explain humic acid sodium/diatomite behavior in the adsorption of tetracycline in water (each with R2 ≥ 0.99), and the effects of surface behavior in multilayer adsorption and electrostatic attraction on uneven heterogeneous adsorption. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
40. Effects of diatom content on rheological properties of marine diatomite.
- Author
-
Yiqing Xu, Xianwei Zhang, Gang Wang, Xinyu Liu, and Lei Yan
- Subjects
- *
DIATOMACEOUS earth , *RHEOLOGY , *KAOLIN , *DIATOMS , *HERSCHEL-Bulkley model , *YIELD stress - Abstract
Diatomites, or natural soils containing diatoms are found in the marine environment all over the world. Diatomites tend to have skeleton microstructures, resulting in unique rheological behaviors. In marine areas, the rheological behavior of diatomite significantly contributes to geohazards, especially submarine landslides. Predicting and preventing submarine landslides require a profound understanding of the rheological characteristics of diatomites. Therefore, to assess the rheological characteristics of diatomite with different diatom and water contents, we prepared different diatom-kaolin mixtures (diatom contents ranging from 0 to 100% and water contents from 66.8% to 640 %) and subjected them to rheological shearing tests. The Herschel-Bulkley model and the Cheng's model were used to analyze the critical rheological parameters (i.e., dynamic and static yield stresses) and the flow behaviors of the samples. The results show that kaolin mixed with 20% diatoms exhibits the highest value in yield stress. Also, the addition of diatoms alters the microstructure of kaolin which may lead to static yield at low water content and shear thickening at high water content. This study offers valuable references regarding critical rheological parameters and flow regimes for simulating submarine landslides in regions covered by natural sediments containing diatoms. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
41. High-temperature CO2 sorption over Li4SiO4 synthesized from diatomite: study of sorption heat and isotherm modeling.
- Author
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Messabih, Khedidja, Bendjaballah-Lalaoui, Nadia, and Boucheffa, Youcef
- Subjects
DISTRIBUTION isotherms (Chromatography) ,DIATOMACEOUS earth ,SORPTION ,CARBON sequestration ,HIGH temperatures - Abstract
The Li
4 SiO4 seems to be an excellent sorbent for CO2 capture at post-combustion. Our work contributes to understanding the effect of the natural Algerian diatomite as a source of SiO2 in the synthesis of Li4 SiO4 for CO2 capture at high temperature. For this purpose, we use various molar % (stoichiometric and excess) of calcined natural diatomite and pure SiO2 . To select the best composition, CO2 sorption isotherms at 500 °C on the prepared Li4 SiO4 are obtained using TGA measurements under various flows of CO2 in N2 . The sorbent having 10% molar SiO2 in diatomite (10%ND-LS) exhibits the best CO2 uptake, probably due to various factors such as the content of the different secondary phases. A comparative study was performed at 400 to 500 °C on this selected 10%ND-LS and those with stoichiometric composition obtained with diatomite and pure SiO2 . The obtained isotherms show the endothermic character of CO2 sorption. In addition, the evolution of isosteric heat highlights the nature of the involved CO2 /Li4 SiO4 interactions, by considering the double-shell mechanism. Finally, the experimental sorption isotherms are confronted with some well-known adsorption models to explain the phenomenon occurring over our prepared sorbents. Freundlich and Jensen–Seaton models present a better correlation with the experimental results. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
42. Vapor-Assisted Synthesis of Nanosized Beta-Zeolite from Natural Ores and Using as Efficient Catalysts for Baeyer–Villiger Oxidation.
- Author
-
Si, Jiwen, Guo, Ruifeng, Qiu, Fagui, Ning, Weikun, Sun, Yanbin, Li, Wenqing, Tao, Qinglong, and Miao, Shiding
- Abstract
The nanosize Beta-zeolites with hierarchical structures were time efficiently synthesized from natural diatomite and ball clays under 150 °C via a vapor-assisted method with the absence of solvents and F
– anions. The Sn-(IV) species were incorporated within frameworks of the presynthesized Beta-zeolite using a modified treatment of acid and tetraethylammonium hydroxide (TEAOH). The dealumination and reconstruction of zeolite frameworks were essential. A high atomic ratio of Si/Sn = 63.95 was obtained and the Sn-(IV) species were in a tetrahedral coordination in the zeolite framework, as confirmed by various characterizations. The Sn-Beta zeolites show excellent performance in the Baeyer–Villiger oxidation reaction for the conversion of cyclohexanone to ε-caprolactone, with 63.3% conversion of cyclohexanone and superior selectivity for ε-caprolactone. The durability and stability of the catalyst was acceptable, as evidenced by a slight decrease in conversion of only 2.5% after 5 catalytic runs. These demonstrated a prototype practice in synthesizing Sn-Beta zeolites from natural ores and applicable catalysis in green chemistry. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
43. 橡胶-硅藻精土复合改性沥青的制备及机理.
- Author
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谭波, 粟友良, 谢恩连, 刘敬霜, and 陈平
- Abstract
In order to improve the high-temperature performance of asphalt, a variety of composite modified asphalts with different proportions of rubber and diatomite were prepared. The performance of various modified asphalt formulations was assessed through tests measuring penetration, softening point, ductility, and rotational viscosity. Subsequently, the optimal modifier blending ratios were determined using response surface methodology. The modification effects were evaluated by comparing them to rubber asphalt and rubberSBS composite modified asphalt. The aging properties, high-temperature performance, microstructure, and reaction mechanisms of the rubber-diatomaceous earth composite modified asphalt were investigated through rotational thin-film oven aging tests, thermal gravimetric analysis, differential scanning calorimetry, Fourier-transform infrared spectroscopy analysis, and scanning electron microscopy analysis. The results indicate that the composite modified asphalt with 22% rubber and 4% diatomite exhibits the best overall performance. Compared to rubber asphalt and rubber-SBS composite modified asphalt, the rubber-diatomite composite modified asphalt demonstrates superior high-temperature stability. There is mainly physical blending between rubber powder, diatomite, and matrix asphalt. Asphalt and the two form a uniform and stable whole that is fixed to each other. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
44. Enhancement of fire safety in epoxy resin composites through incorporation of microencapsulated diatomite.
- Author
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Jin Wang, Xiaoyue Shen, Mengwei Jiang, Fang Zhou, and Yupeng Zhang
- Subjects
FIRE prevention ,DIATOMACEOUS earth ,EPOXY resins ,HEAT release rates ,FIREPROOFING ,COMBUSTION gases ,SMOKE ,ENTHALPY - Abstract
Diatomite (DIA) particles are commonly employed as flame-retardant additives for polymers, yet their intrinsic inefficiency requires substantial quantities for optimal efficacy. To address this issue, we proposed a novel approach involving the microencapsulation of DIA with polyethylene glycol phosphate (PEGP) to enhance the flame retardancy of epoxy resin (EP). Characterization of the prepared DIA@PEGP utilized scanning electron microscopy with energy-dispersive x-ray spectrometry and Fourier transform infrared spectroscopy. The resulting EP composite, DIA@PEGP-4/EP, achieved a limiting oxygen index of 33.2% and achieved a V-0 level in vertical combustion tests. Compared to EP, DIA@PEGP-4/EP demonstrated significantly improved fire performance, with 38.6%, 47.8%, 25.0%, 41.3%, and 60.4% reduction in peak heat release rate, total heat release, peak smoke production rate, total smoke production, and CO yield. Furthermore, the highest FPI value of 0.080 m2·s/kW for DIA@PEGP-1/EP and the lowest FGI value of 8.734 kW/m2·s for DIA@PEGP-4/EP, indicate that the incorporation of DIA@PEGP into EP enhances its fire safety. The flame retardancy mechanism of DIA@PEGP-4 involves the formation of a phosphorus-containing aromatic carbon layer during EP char formation, capturing radicals in the gas phase during combustion. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
45. Obtaining New Biocompatible Composite Materials with Antibacterial Properties Based on Diatomite and Biologically Active Compounds.
- Author
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Kabieva, Saule, Zhumanazarova, Gaziza, Zhaslan, Rymgul, Zhumabayeva, Gulistan, Ukhov, Arthur, Fedorishin, Dmitry, Gubankov, Alexander, Tarikhov, Farkhad, Yerkhan, Ordabay, Irina, Kurzina, Yerkassov, Rakhmetulla, and Bakibaev, Abdigali
- Subjects
- *
DIATOMACEOUS earth , *BIOMEDICAL materials , *BIOACTIVE compounds , *COMPOSITE materials , *ANTIBACTERIAL agents , *X-ray photoelectron spectroscopy , *BLOOD proteins - Abstract
This study aimed to create new composite materials based on diatomite—a non-organic porous compound—through its surface modification with bioactive organic compounds, both synthetic and natural. Chloramphenicol, tetrahydroxymethylglycoluril and betulin were used as modifying substances. Composite materials were obtained by covering the diatomite surface with bioactive substance compounds as a solution and material dispersion in it. The materials were characterized by IR spectroscopy, SEM and X-ray photoelectron spectroscopy. For the biocomposites, the hemolytic effect, plasma proteins' adsorption on the surface and the antibacterial activity of the obtained materials were studied. Results show that the obtained materials are promising for medicine and agriculture. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
46. Geotechnical characterization of the diatomaceous silty soil in Walvis Bay, Namibia: mechanical properties and interpretations of CPTu records.
- Author
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Li, Jianyu, Lin, Hongjie, Zhang, Yue, Yang, Hongwei, and Liu, Jiankun
- Abstract
Diatomaceous soils as a special soil containing diatom frustules are widely distributed in marine deposits. Although their soil properties have been partially tested and reported which exhibit high void ratio and compressibility, a thorough investigation is in lack. Moreover, the interpretation of the cone penetration test (CPTu), a widely-used in-situ test, to the properties of such soil is still unknown, hindering a proper estimation of the diatomaceous soils in engineering geology and geotechnical practice. This study reports the soil properties and mechanical behavior of the undisturbed diatomaceous soil obtained from Walvis Bay in Namibia, which shows that the soils had an extremely high void ratio (~ 4.39) and low specific gravity (~ 2.16), and consequently low density and high compressibility. Due to the porous property of diatom frustules, the diatomaceous soils also exhibited a high liquid limit and plastic limit. Although these properties provide an identification to super soft soils, the diatomaceous soils had discrepant mechanical properties, i.e., the values of strength parameters in diatomaceous soils were higher than those in typical soft soils. At the end, by comparing the results of strength parameters obtained from the laboratory tests on undisturbed soil samples and the in-situ CPTu records, this paper proposes the interpretation methods of CPTu results to the strength parameters (effective friction angle and undrained shear strength) in the diatomaceous soils. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
47. Experimental Study of the Moisture Resistance of Cement Mortar Using Pozzolan Materials and Calcium Stearate.
- Author
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Park, Jang Hyun and Yoon, Chang Bok
- Subjects
- *
MORTAR , *CALCIUM , *POZZOLANIC reaction , *PARTICULATE matter , *DIATOMACEOUS earth , *CEMENT - Abstract
Nanosilica and diatomite are pozzolanic resources rich in SiO2. In this study, the purpose of this study was to improve the moisture resistance of the specimen by producing a mixed material using pozzolanic materials and calcium stearate and adding it to cement mortar while stirring. The results showed that the hydration reaction was not activated when calcium stearate adhered to the fine particles of nanosilica; it existed simply in the form of a filler inside the specimen. Diatomite, due to its atypical particles and porosity, may have greater water tightness than nanosilica because of the pozzolanic reaction in particles to which calcium stearate is not attached. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
48. 钒酸铋基复合光催化剂的制备及性能研究.
- Author
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刘景景
- Abstract
Copyright of Iron Steel Vanadium Titanium is the property of Iron Steel Vanadium Titanium Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2024
- Full Text
- View/download PDF
49. Geology, mineralogy, geochemistry and genesis of volcano-sedimentary hosted Lake Abiyata diatomite in central main Ethiopian Rift
- Author
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Yirgalem Hunegnaw and Worash Getaneh
- Subjects
Amorphous silica ,Diatomite ,Genesis ,Lacustrine ,Mineralogy ,Science (General) ,Q1-390 ,Social sciences (General) ,H1-99 - Abstract
The Abiyata Diatomite deposit is located in the Main Ethiopian Rift, which is characterized by strong extensional tectonics. The deposit is mostly made up of diatomaceous earth, which is a sedimentary rock made up of the fossilized remnants of diatoms, which are tiny algae. Diatomite's geological, geochemical, and mineralogical features, as well as its formation, are discussed in this research. To characterize diatomite from Abiyata, chemical, mineralogical, technological, and micro paleontological examinations were conducted on samples collected from outcrops and stream sections. The XRD characteristic peaks of diatomite demonstrate that it is primarily made up of Opal A silica, however certain crystalline phases were discovered in adequate amounts. Quartz and feldspar were the predominant crystalline phases, with lesser amounts of Calcite, Cristobalite, Illite, Mordinite, Wairakite, Halloysite, Clinoaptilolite, Adularia, and Tridymite. From SEM photomicrographs diatomites are primarily formed of benthic freshwater diatom species such as Staurosirella pinnata, Staurosira construens, Pseudostaurosira brevistriata, Epithemia Sorex and surirella pinnata. Diatom species, sedimentary profile sections and mineralogical data suggest that diatomite was deposited in lacustrine-type freshwater shallow lake environment. Chemical data obtained from 10 diatomite samples show that while silica is the bodybuilding material for diatomite. i.e., Silica (SiO2), 76.9 %; Alumina (Al2O3), 3.49 %; Sodium Oxide (Na2O), 1.52 %; Potassium Oxide (K2O), 1.107 %; Iron Oxide (Fe2O3), 1.1 %; Loss on ignition (LOI) 13.7 and other oxides are below 1 %. Studies from technological properties like physical tests, chemistry, and mineralogy and micropaleontology of Abiyata diatomite suggest that calcined diatomite can be used for waste treatment processes in the filter aid industry and as filler material.
- Published
- 2024
- Full Text
- View/download PDF
50. Performance evaluation of asphalt binders incorporating surface-modified diatomite and bio-oil: A value-added utilization of natural resource
- Author
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Youyun Li, Tao He, and Jianliang Tang
- Subjects
Asphalt binder ,Asphalt mixture ,Diatomite ,Bio-oil ,Rheological properties ,Materials of engineering and construction. Mechanics of materials ,TA401-492 - Abstract
To study the effect of surface-modified diatomite (SMD) on bio-asphalt performance, the asphalt binders incorporating SMD and bio-oil (SMDB) was prepared with different dosages. The high-temperature characteristics of SMDB were assessed by consistency test, viscosity test, and dynamic shear rheometer (DSR). Meanwhile, the low-temperature characteristics of SMDB were evaluated by bending beam rheometer (BBR) and ductility test. The compatibility of SMDB was assessed by a storage stability test and a Fluorescence microscope (FM). The adhesion and chemical composition of SMDB were analyzed using the sessile drop method and Fourier transform infrared (FTIR) spectroscopy, respectively. Finally, the moisture stability and high-temperature properties of the SMDB mixture were studied using the tensile strength ratio (TSR) test and wheel track test, respectively. The preliminary results of this work show that the addition of SMD increases the viscosity, softening point, fatigue index, and rutting factor of asphalt and reduces the penetration. It is found that SMD improves the anti-aging performance, adhesion performance, and high-temperature stability of SMDB. Although SMD has a negative effect on the low-temperature properties and fatigue resistance of asphalt, the characteristics of SMDB at low temperatures are still superior to those of virgin asphalt. SMD at low content had little effect on the fatigue resistance of the bio-asphalt. Moreover, it is found that SMD is better than the original diatomite in enhancing bio-asphalt properties more significantly. In addition, the blending among SMD, asphalt matrix, and bio-oil is the physical modification, and the mixture has excellent storage stability. Finally, the mixture property testing results indicate that SMD improves the rutting and moisture resistance of the SMDB mixture.
- Published
- 2024
- Full Text
- View/download PDF
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