Search

Natural rubber (NR) composites reinforced with sepiolite and crosslinked with phenolic resin were prepared. Effects of compatibilizer types and contents, namely 3-aminopropyl triethoxysilane (APTES) or epoxidized NR (ENR50), on curing, tensile, strain-induced crystallization, and stress relaxation were investigated. Compared to APTES, ENR50 provided a greater compatibilizing effect in the NR composites. The ENR50 introduced strong physical and chemical interactions between sepiolite and NR, while only physical interaction was present in the APTES compatibilized composites. Stronger interaction between rubber and sepiolite improved filler dispersion, swelling resistance, and tensile strength; and delayed stress relaxation of the composite. Increased addition of ENR50 improved the modulus and tensile strength, and the greatest tensile strength was achieved at 2 phr ENR50 with a 15% improvement over composite without compatibilizer. In the case of APTES, 2 phr level enhanced tensile strength, but a further increase in APTES content degraded tensile, swelling resistance, and stress relaxation responses, due to its plasticizing effect. Moreover, ENR50 enhanced the strain-induced crystallization and delayed stress relaxation of the composites more than APTES. Weaker interaction between rubber and filler in APTES filled composites was due to having only hydrogen bonds formed between rubber and filler, in addition to crosslinks. [ABSTRACT FROM AUTHOR]

Soil cadmium contamination is a global environmental issue, threatening ecosystem health and human safety. Common remediation strategies, including phytoremediation and soil replacement, are typically hampered by their lengthy processes or high costs. The aim of this review is to explore and evaluate innovative physical and chemical remediation techniques to address cadmium pollution effectively. This review focuses on three promising approaches: the co-application of phosphate fertilizers and sepiolite, CaAl-layered double hydroxide (LDH) immobilization, and hydrochar treatments. The primary methodologies involved evaluating the adsorption capacity, ion exchange mechanisms, and remediation efficiency under varying environmental conditions. Results indicate that these techniques significantly enhance cadmium immobilization, with the co-application of phosphate fertilizers and sepiolite demonstrating up to 72.6% removal of HCl-extractable cadmium. The review concludes that these techniques offer superior cost-effectiveness and scalability for large-scale applications and recommends future research to optimize amendment formulations and develop renewable adsorbents to further improve sustainability. [ABSTRACT FROM AUTHOR]

Development of drug delivery systems is an extensively researched area in the biomedical field. In recent years, there has been an increasing interest in fabrication of biocompatible nanofibrous drug delivery systems. The present study describes the fabrication of calcium chloride‐crosslinked bionanocomposite hydrogels based on pectin for the use of gastro‐retentive delivery system. Sepiolite/famotidine/pectin nanocomposite hydrogel was fabricated by using Ionotropic gelation process. The thermal, structural and morphological properties were evaluated via different experimental techniques such as TGA‐DSC, FTIR, and SEM. The prepared hydrogels showed a pH sensitive swelling profile with maximum water absorption at pH 1.2. Analysis of in‐vitro drug release data revealed that the sepiolite/famotidine/pectin nanocomposite hydrogels exhibited a slight initial burst release, followed by a sustained release over a 24 h period. This was observed both in simulated gastric fluid and in phosphate‐buffered saline, suggesting that these hydrogels are well‐suited for prolonged drug delivery. To investigate the drug release kinetics, various models were applied. The release of famotidine was predominantly governed by diffusion, as described by the Korsmeyer‐Peppas model. [ABSTRACT FROM AUTHOR]

This review critically examines the latest advancements in clay mineral-based photocatalysts for water purification. Clay minerals, owing to their natural abundance, low cost, and unique physicochemical properties, have emerged as promising candidates for enhancing photocatalytic efficiency. This article delves into various activation methods for clay minerals, including acid, alkali, calcination, and mechanochemical activation, highlighting their roles in enhancing surface area, creating active sites, and improving photocatalytic performance. Moreover, the review explores various modification strategies for photocatalysts, such as doping with metal and non-metal ions, deposition of metals, and the design of heterojunctions, to further boost photocatalytic activity. In particular, the utilization of kaolinite, montmorillonite, attapulgite, and sepiolite as clay mineral supports for photocatalysts is discussed in detail, showcasing their potential in wastewater treatment. The review underscores the significant strides made in the development of clay mineral-based photocatalysts, highlighting their effectiveness in degrading organic contaminants under light exposure. Nevertheless, there are persisting challenges such as the optimization of loading quantities, improvement in compatibility between clay minerals and photocatalysts, and reduction in preparation costs for large-scale applications. In summary, this review offers valuable insights into the current status of clay mineral-based photocatalysts for water purification, thereby stimulating future research in this promising field. [ABSTRACT FROM AUTHOR]

In the northern part of the Niğde (Central Anatolian) Quaternary Bor Basin, stratigraphic sections P1 and P2 were sampled, reaching depths of 11 m and 25 m. The samples were analyzed with thin-section, XRD, and chemical analyses (ICP-MS) to determine their chemical and mineralogical properties. In the study area, partially lithified volcano-sedimentary rocks comprised paleosol, calcrete, gravel, sand, silt, mud, clay, and volcanoclastics such as pumice fall-out. Grain size analyses from the Zengen (P1) and Altunhisar (P2) regions showed very poor sorting and strong positive skewness. The Zengen-area (P1) samples contained rock fragments, calcite, quartz, opal-CT, feldspar, amphibole, pyroxene, biotite, and clay minerals such as smectite, chlorite, illite, palygorskite, and sepiolite. In calcrete zones, however, the amounts of CaO increased, whereas significant decreases in the amounts of SiO2 were observed. Therefore, a negative correlation between SiO2 and CaO was observed. The vertical distributions and behaviors of trace elements in the Zengen-area profile showed variation with the different levels of the P1 section. It is thought that in the Bor Plain, after 17,000 years ago, no lacustrine phase reached a level above the periglacial lake level in the region, reaching this level with the melting of the ice sheets in the area. During the late glacial period, shallow freshwater lacustrine phases and paleosols were identified from 12,500 to 11,000 yr BP in the basin. [ABSTRACT FROM AUTHOR]

Mixed plastic fraction (MPF) from marine litter was investigated as a pore-forming agent in formulations with kaolin and a rejected Mg-clay (rich in smectite and sepiolite) to obtain innovative zeolitic lightweight aggregates. Round granules of ~10 mm in diameter were shaped and fired at 600 °C (mixtures of kaolin with 0, 5, 10, and 20 wt.% MPF) and 900 °C (mixtures of rejected Mg-clay:kaolin (1:0, 2:1, 1:2; 0:1) with 10 wt.% MPF). The fired specimens were hydrothermally treated in a 3M NaOH solution at 150 °C for 24 h. Mixtures containing 20 wt.% MPF led to specimen crumbling, while those with 5 and, especially, 10 wt.% MPF favored a significant crystallization of zeolites and feldspathoids (50–80%), highlighting cancrinite, nepheline, zeolite A, and analcime. The resulting materials were lightweight (1.5–1.8 g/cm3) and their crushing strength increased substantially with the hydrothermal treatment, from 0.04–0.5 MPa to 2.3–5.5 MPa after zeolitization. High content of rejected Mg-clay in the mixture (>67%) negatively affected the zeolitization and the properties of the final aggregate, while 33 wt.% was adequate, increasing slightly the crushing strength (3.4 vs. 3.1 MPa). These findings contribute to plastic waste circularity and sustainability/technological progress in materials production. [ABSTRACT FROM AUTHOR]

Nanofibrous clay minerals, specifically palygorskite (Pal) and sepiolite (Sep), have been becoming a new generation of rheological additives for drilling fluid systems due to their unique nanostructure, high performance, environmentally benign nature, and cost-effectiveness. These nanoclay minerals exhibit excellent colloidal and rheological properties in aqueous systems, even in saline and high-temperature environments. Although Pal and Sep have been employed as auxiliary rheological additives in a few cases to enhance the salt resistance of conventional water-based drilling fluids (WBDFs), these two clay minerals have not yet been used on a large scale due to a lack of understanding of their structures and properties, as well as the control of their performance. This paper presents a comprehensive review of the clay mineralogy, colloidal chemistry, rheological behaviors, and filtration properties of nanofibrous clay minerals in WBDFs, with critical comments. It also discusses the challenges and prospects for further research. This review provides new insights into fundamental and applied studies of nanofibrous clay minerals and helps promote the large-scale application of nanofibrous clay products in drilling fluids. [ABSTRACT FROM AUTHOR]

The objective of the paper is to investigate the effect of organo‐modified sepiolite (MSep) on morphology, mechanical, and viscoelastic properties of polyamide‐11 (PA11) prepared by melt compounding at 5 wt.%. The study reveals that the addition of both unmodified sepiolite (USep) and organo‐MSep to PA11 improves the reinforcement effect of the nanocomposite materials compared to neat PA11, being however more pronounced for the organo‐modified one. Indeed, morphological analysis by transmission electron microscopy (TEM) shows a finer dispersion of organo‐MSep in PA11 matrix than the unmodified one, which is characterized by a significant presence of fibers aggregates in number and size. Further, dynamic mechanical analysis (DMA) results are in a good agreement with both tensile properties and TEM observations. [ABSTRACT FROM AUTHOR]

To enhance the high-temperature adaptability of copper-based composite materials and C--C/SiC discs, this article innovatively introduces a method of replacing graphite with sepiolite, resulting in the successful fabrication of samples with exceptional mechanical and friction properties. The results reveal that moderate incorporation (less 6%) of sepiolite provides a particle reinforcement effect, resulting in an improvement of mechanical properties. Interestingly, the addition of sepiolite causes a change in the traditional saddle-shaped friction curve due to high temperature lubrication. Meanwhile, the primary advantage of sepiolite lies in its superior abrasion resistance, evident in the increased friction coefficient and altered wear mechanisms with higher sepiolite content. The wear resistance is optimal at 200 Km/h (400 °C). Particularly, the unique composition of the friction layer (outermost layer: a composite film consisting of B2O3, sepiolite, graphite, and metal oxide films; intermediate layer: metal oxide films) plays a pivotal role in improving friction stability. Finally, there are significant optimizations in the GA algorithm, especially GA-GB model has the best prediction effect on the maximum friction temperature. [ABSTRACT FROM AUTHOR]

The presence of heavy metals and pollutant dyes can have detrimental effects on aquatic ecosystems and compromise aquatic aesthetics. This study investigates the use of unprocessed waste gem meerschaum powder as a new adsorbent in the removal of both Cu(II) and methylene blue (MB) from aqueous solutions to reduce water pollution. The structure of the waste powder was characterized by FT-IR, XRD, SEM and BET methods. Optimization of Cu(II) and MB dye removal was carried out using design of experiment technique. Under optimum conditions, remarkable removal efficiencies of 95.5% (± 3.7) for Cu(II) and 97.8% (± 0.4) for MB were achieved. The removal of Cu(II) followed the Freundlich isotherm model, while the removal of MB dye adhered to the Langmuir isotherm model. Both adsorption processes obeyed the pseudo-second-order kinetic model and occurred spontaneously. This innovative approach offers a promising solution to water pollution by highlighting the importance of sustainable and cost-effective waste use. [ABSTRACT FROM AUTHOR]

The organic xerogel (OX) was synthesized through sol–gel polymerization of formaldehyde and resorcinol in inverse emulsion using Na2CO3 as a catalyst. Meanwhile, OX containing sepiolite (OX-Sep) and vermiculite (OX-Ver) were prepared similarly to OX but adding clays during synthesis. All materials were mesoporous and presented spherical morphology, and the surface of these materials exhibited an acidic character because the concentration of acidic sites was higher than those of basic sites. Cd(II) adsorption from aqueous solutions onto OX, OX-Sep, and OX-Ver was examined, and the OX-Sep showed the highest adsorption capacity towards Cd(II) of 189.7 mg/g, being 1.5, 2, and 36 times higher than that of OX-Ver, OX, and Sep. The OX-Sep capacity for adsorbing Cd(II) was significantly lessened by decreasing the pH from 7 to 4 and raising the ionic strength from 0.01 N to 0.1 N. This trend was ascribed to electrostatic attraction between the Cd+2 in water and the negatively charged surface of OX-Sep. Besides, desorption studies at pH 4 showed that the average desorption percentage of Cd(II) adsorbed on OX-Sep was 80%. The characterization results and the effect of the operating conditions on the adsorption capacity proved that electrostatic attraction and cation exchange play a crucial role in the adsorption mechanism. [ABSTRACT FROM AUTHOR]

As a common method for preparing micron powder in industrial operations, the mechanical extrusion method simply pursues the particle size without considering the microstructure characteristics of sepiolite, which leads to problems such as bundles of sepiolite not being effectively dispersed, and thus the disruption of fibers is inevitably caused. In this work, a new micronization method for disaggregating these bundles while preserving the original structural integrity of the fibers is proposed based on steam pressure changes. The effects of steam pressure changes on the particle size distribution, microstructure, and properties of treated sepiolite are studied using X-ray fluorescence spectrometer (XRF), X-ray diffractometer (XRD), Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy (TEM), and a specific surface area and aperture analyzer (BET). The experimental results show that the particle size of sepiolite powder depends greatly on steam pressure, and sepiolite powder with mass ratio of 91.6% and a particle size D97 of 21.27 μm is obtained at a steam pressure of 0.6 MPa. Compared to the sepiolite after mechanical extrusion, the sepiolite treated with steam pressure changes can maintain the integrity of its crystalline structure. The specific surface area of sepiolite enhanced from 80.15 m2 g−1 to 141.63 m2 g−1 as the steam pressure increased from 0.1 to 0.6 MPa, which is about 1.6 times that of the sample treated with mechanical extrusion. [ABSTRACT FROM AUTHOR]

A carbon paste sensor was modified with sepiolite clay particles (SC/CPE) to quantify the bicalutamide (BICA). BICA's probable oxidation mechanism and the interaction between calf thymus DNA (dsDNA) were investigated (in aqueous medium, pH 4.8) for the first time. Cyclic voltammetry (CV), Electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM) were used for the investigation of surface morphology and electrochemical characteristics. The effect of the amount of SC, supporting electrolyte, and pH was optimized. Under optimum conditions, the developed sensor exhibited a linear response between 0.223 and 20.0 μM. The detection of the limit was found to be 0.069 μM. The sensor was successfully applied to quantify BICA in biological and pharmaceutical samples. Finally, cyclic voltammetry (CV) and differential pulse voltammetry (DPV) provided new insight into the interaction between BICA and ds‐DNA. The kinetic parameters for the free DNA, diffusion coefficient (D), heterogeneous rate constant (ks), and electrode surface concentration (Γ) were calculated to be 4.22×10−5 cm2 s−1, 0.57 s−1 and 7.67×10−9 mol cm−2, respectively. The (ds‐DNA)‐BICA complex parameters were 4.56×10−6 cm2 s−1, 0.70 s−1, and 1.61×10−9 mol cm−2. In addition, binding constant (K) and Gibbs free energy change (ΔG°) were 6.02×105 M−1 and −32.97 kJ mol−1, respectively. [ABSTRACT FROM AUTHOR]

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety of sepiolite as a technological feed additive for all animal species. In 2022, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) delivered an Opinion on the safety and efficacy of the same additive. The Panel concluded that sepiolite used as a feed additive is safe for the consumers and the environment, and efficacious as a thickener‐suspending agent, binder and anticaking agent in feed for all animal species under the proposed conditions of use. The additive was not considered an eye or skin irritant. However, it was considered a respiratory irritant, a respiratory and dermal sensitiser; owing to the dusting potential and its silica content, the additive was considered a risk by inhalation. Regarding the target species, in the previous Opinion, the Panel concluded on the safety of the additive for dairy ruminants. However, no conclusion could be drawn for all other species/categories. Based on the tolerance studies in chickens for fattening, weaned piglets and trout evaluated in the current assessment, and the one in dairy cows previously assessed, the Panel concluded that the inclusion of sepiolite at the maximum recommended level of 20,000 mg/kg complete feed is safe for all animal species. [ABSTRACT FROM AUTHOR]

Polyvinyl alcohol (PVA) hydrogel has attracted significant attention in the field of biomedicine, sensors, and other related areas due to their exceptional biocompatibility and interfacial properties. However, conventional single‐component hydrogels often face challenges associated with insufficient mechanical and rheological properties, lacking the structural strength required for practical applications. This study aims to investigate the impact of introducing sepiolite on the rheological behavior of PVA hydrogels. To this end, sepiolite/PVA composite hydrogels were fabricated using a chemical cross‐linking technique. Subsequently, a comprehensive series of rheological experiments was conducted to assess their properties. Experimental results and model comparisons demonstrate that fractional order constitutive equations can accurately describe the rheological behavior of the hybrid hydrogels. With the increase of sepiolite content in the hydrogel, the critical strain does not change significantly, but both the storage modulus and loss modulus of the hydrogel gradually increase. When the sepiolite content reaches 10 wt %, the tensile strength of the composite hydrogel at the yield point jumps to 17.07 kPa, and the toughness increases to 549.69 kJ/m3. This significant improvement in toughness is accompanied by a fracture strain of approximately 4000 %. By adjusting the sepiolite content, different rheological properties can be achieved. [ABSTRACT FROM AUTHOR]

Alumina (Al2O3) ceramics are widely used in electronics, machinery, healthcare, and other fields due to their excellent hardness and high temperature stability. However, their high brittleness limits further applications, such as artificial ceramic implants and highly flexible protective gear. To address the limitations of single-phase toughening in Al2O3 ceramics, some researchers have introduced a second phase to enhance these ceramics. However, introducing a single phase still limits the range of performance improvement. Therefore, this study explores the printing of Al2O3 ceramics by adding two different phases. Additionally, a new gradient printing technique is proposed to overcome the limitations of single material homogeneity, such as uniform performance and the presence of large residual stresses. Unlike traditional vat photopolymerization printing technology, this study stands out by generating green bodies with varying second-phase particle ratios across different layers. This study investigated the effects of different contents of sepiolite fiber (SF) and 316L stainless steel (SS) on various aspects of microstructure, phase composition, physical properties, and mechanical properties of gradient-printed Al2O3. The experimental results demonstrate that compared to Al2O3 parts without added SF and 316L SS, the inclusion of these materials can significantly reduce porosity and water absorption, resulting in a denser structure. In addition, the substantial improvements, with an increase of 394.4% in flexural strength and an increase of 316.7% in toughness, of the Al2O3 components enhanced by incorporating SF and 316L SS have been obtained. [ABSTRACT FROM AUTHOR]

Natural sepiolite has great potential for application in wound healing, haemostasis and medicines. This paper introduces a versatile solid-state sintering technique for preparing sepiolite-based nanocomposites with enhanced antibacterial properties, and the physical, structural, rheological and antibacterial properties of which were determined to be enhanced. The incorporation of nanosized Ag and metal oxides into sepiolite composites results in a notable improvement in their antibacterial efficacy against Escherichia coli and Staphylococcus aureus in comparison to the unmodified sepiolite. With a low silver content of just 5%, the sepiolite–Ag composite achieves an antibacterial rate of ~100%. Furthermore, the rheological properties exhibited by the sepiolite composites are noteworthy, suggesting their suitability for use in wound-dressing applications due to their exceptional workability. The methodology employed in this research has the potential to offer a viable substitute for the production of economical and effective natural antibacterial nanocomposites. [ABSTRACT FROM AUTHOR]

Sepiolite is a fibrous clay mineral, which is mostly associated with a semi-arid to arid climate, with characteristics intermediate between kaolinite and montmorillonite minerals. An experimental study was conducted, with the goal of creating a substantial database of physical, microstructural, and geotechnical characteristics of sepiolite to develop its applications as a natural resource that is explored as the main deposit of Iran. It has been found that sepiolite soils were lightweight, porous, and cohesive with negligible settlement and swelling properties and almost high UCS values. Various analysis were performed to characterise the macroscopic behaviour (Atterberg limit, physical, and compressibility tests), microstructural, chemical, and mineralogical characterisations by chemical analysis, X-Ray diffraction, and Scanning Electron Microscopy. At first glance, sepiolite soils showed high liquid limits with medium to high plastic indices which can result in problems including creation of up and down movements in foundations. After mixing with silt and fine sand to decrease high liquid limit and optimum moisture amounts, sepiolite is suitable candidate for engineering applications (including clay liners, clay cores, etc.) due to its compressibility and strength characteristics. In conclusion, sepiolite soils are strongly recommended for geo-environmental structures due to their adsorption capacity, low permeability coefficient, and suitable strengths. [ABSTRACT FROM AUTHOR]

As a key component of lithium-ion batteries, a separator with excellent electrolyte wettability and good thermal stability has an important impact on the overall performance of lithium-ion batteries. Herein, a PVDF/sepiolite electrospun layer was coated on one side of the PP separator via electrospinning technology to prepare the composite separator (xMS-PVDF@PP) with sepiolite nanofibers modified with vinyltriethoxysilane (VTES) to ameliorate their dispersibility and compatibility with PVDF polymer matrix. The effect of modified sepiolite addition amounts on the physical and electrochemical properties of composite separator was intensively studied. It is found that the as-prepared xMS-PVDF@PP composite separator displays enhanced porosity, electrolyte uptake, thermal stability and Li + ion transport kinetics than pristine PP separator. Specifically, Li|LiFePO4 battery with 20MS-PVDF@PP as separator shows the best rate and cycling performance, with a specific discharge capacity of 115.3 mAh·g-1 at 10C rate and a capacity retention rate of 97.06% after 200 cycles at 1C rate. The sepiolite in the electrospun layer can immobilize PF6 – anion to facilitate the uniform distribution of Li + ions and then inhibit the lithium dendrite growth, as well as absorb HF to alleviate Fe2+ dissolution from LiFePO4 cathode, thereby further improving the electrochemical performance of LiFePO4 battery [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate the effects of different clay-based additives, which are physically added to water-based paints used in the chemical industry, on the physical strength of paints. For this purpose, three different clay-based additives (kaolin, montmorillonite and sepiolite) were added in three different amounts (0.5-1-2%) to commercial waterborne paints (Ral 6034, Ral 7012, Ral 9003) supplied in three different colors for paint tests and the effects of these additives on some paint properties were studied. As a result of the tests, gloss, cross-cut adhesion class, colorimetry and FT-IR results comparable to those of commercial waterborne coatings without additives were obtained. The values closest to the test results of paints without additives were obtained with the combinations of "Ral 6034+1% kaolin", "Ral 7012+2% mmt" and "Ral 9003+0.5% kaolin". Without deteriorating the other properties of these paints, an increase of 11.1%, 55% and 3.9% was observed for the combinations of "Ral 6034+1% Kaolin", "Ral 7012+2% mmt" and "Ral 9003+0.5% Kaolin", respectively. [ABSTRACT FROM AUTHOR]

The continuous growth of population and urbanization in the world significantly increases the demand for cement. In terms of sustainability, the cement industry needs to develop new and effective pozzolans with the appropriate recycling of alternative raw materials. It is also important to evaluate sepiolite, which has very limited resources in the world compared to other industrial minerals and whose economic deposits are limited to Spain and Türkiye. In this study, the usability of sepiolite as a pozzolan in cement and its effects on physical, mechanical and durability properties were investigated. First of all, the chemical and physical properties of sepiolite in Eskisehir region were investigated. Crude and ground sepiolite calcined at 500 ºC, 700 ºC and 900ºC were substituted for CEM I 42.5 R class standard Portland cement at 5-10-15% and 20% ratios. The pozzolanic activities of produced sepiolite substituted cement were determined according to ASTM C-311. As a result, crude sepiolite retains more water than calcined sepiolite, thus negatively affecting the strength properties of the concrete. Additionally, sepiolite is considered suspicious (harmful-harmless) in terms of alkali silica reactivity except 10%-15%-20% crude sepiolite substitutions. Overall, It has been observed that sepiolite does not have sufficient pozzolanic properties in cementitious composites. [ABSTRACT FROM AUTHOR]

Five phyllosilicates (kaolinite, montmorillonite, saponite, sepiolite and palygorskite) have been selected as starting materials for the synthesis of zeolites. Among them, kaolinite and montmorillonite display the lowest Si/Al molar ratio leading to aluminosilicates with high crystallinity. Thus, the hydrothermal treatment under basic conditions forms 4A zeolite when kaolinite is used as starting material while 13X zeolite is obtained when montmorillonite is used as starting material. The microporosity and CO2-adsorption capacity of the prepared zeolites are directly related to its crystallinity. Thus, in order to improve it, raw phyllosilicates were subjected to a microwave-assisted treatment to remove undesired Mg or Fe-species, which have a negative effect in the assembling of the zeolites by hydrothermal basic conditions in a second step. The highest adsorption value was 3.85 mmol/g at 25 °C and 760 mm of Hg for Mont-A-B sample after the consecutive treatments. [ABSTRACT FROM AUTHOR]

In this study, we synthesized novel, economically efficient phosphonic acid-functionalized grafted sepiolite nanohybrids for selective elimination of copper ions from water. These nanohybrids were prepared by graft polymerization of glycidyl methacrylate onto sepiolite. We utilized free radical graft polymerization to graft glycidyl methacrylate (GMA) onto silanized sepiolite. The nanohybrids obtained exhibited a grafting percentage of 479% at 0.3 g of KPS initiator, 15% GMA monomer, and after 4 h of reaction. In pursuit of selectively removing metal ions from water, the nanohybrid with the highest grafting (PGE3) was chemically treated with phosphoric acid to introduce phosphonic acid groups on it. FTIR, XRD, SEM, CHO analysis, BET, and TGA analysis were utilized to characterize the developed nanohybrids. Batch adsorption studies were carried out using AAS process, examining the impact of pH, adsorbent weight, contact time, adsorbate concentration, and temperature on the adsorption process. Due to the selectivity of phosphonic acid groups towards copper ions, phosphonic acid-functionalized grafted sepiolite nanohybrid (PGE3-P) was used for copper ions removal from its aqueous solution. The maximum adsorption capacity of PGE3-P adsorbents was 134.5 mg/g for copper ions. The data from kinetic studies suggests that the adsorption process of copper ions followed a pseudosecondorder model. Furthermore, Langmuir isotherm proved to be a more fitting model in equilibrium isothermal investigations. The thermodynamic analysis of the data indicates that the adsorption of copper ions by PGE3-P is an endothermic and spontaneous process. The development of this phosphonic acid-functionalized grafted sepiolite nanohybrid adsorbent is a new contribution into the field of adsorption. The developed material can be utilized as selective adsorbent for elimination of other heavy metals from water. [ABSTRACT FROM AUTHOR]

High flame retardancy, satisfactory mechanical properties are crucial for polymeric composites employed in fields with safety requirements. Inorganic fillers can effectively regulate the structure and composition of polymeric materials and have become an effective strategy for fabricating high-performance polymeric composites. Herein, aluminum phosphate–coated sepiolite (Sep@AlPO4) fillers are fabricated as a multifunctional additive to modify polyethylene oxide (PEO), PEO nanocomposites were prepared via incorporation of Sep@AlPO4 and phenethyl-bridged 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) derivative (DiDOPO) in the PEO matrix, and the synergistic effects between Sep and AlPO4 are discussed. The results reveal that Sep@AlPO4 could simultaneously enhance the flame retardancy and strengthen the mechanical properties of PEO/DiDOPO. Additionally, Sep@AlPO4 could increase the viscosity, storage modulus, and loss modulus of the composites. This study provides an effective strategy for fabricating enhanced flame retardants to improve the performance of polymers. [ABSTRACT FROM AUTHOR]

Sepiolite is an important raw fibrous material. A method to prepare red pigments based on sepiolite through the thermal treatment of sepiolite with sulfur and sodium sulfide hydrate is reported. Sepiolite was heated until 800 °C in order to remove zeolitic water, the first coordinated water, the second coordinated water, and structural hydroxyls. Several [S/Na2S]molar ratios in the range 0.5–7 were employed. The properties of these pigments were studied by different analytical techniques, such as colorimetric analysis, thermal analysis, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction and scanning electron microscopy. The samples with [S/Na2S] = 0.5 and 1, corresponding to high contents of sodium sulfide in the synthesis procedure, exhibit high values of the colorimetric parameter CIE a* and a maximum reflectance in the visible zone belonging to red, based on the red colour of the samples. Under the reducing conditions of the synthesis, sulfur forms polysulfides of the general formula [Sx]2−. The sodium sulfide reacts with the excess S to form polysulfides as well. From the polysulfides, the radical anions of the general formula [Sx/2]˙− originate and they are identified as the chromophore groups responsible for the color in the sulfur-based pigment analogues of ultramarines. The red colour of the samples could be mainly attributed to the presence of S4 and S4˙− identified by FTIR. [ABSTRACT FROM AUTHOR]

The purpose of this research was the synthesis of corn silk/sepiolite (CS/SEP) for the elimination of lead and zinc from industrial effluents. The properties of the composite were studied using BET, FT-IR, FESEM, and XRD techniques. Effects of amount of adsorbent, pH, initial concentration, and contact time on lead and zinc heavy metal ions adsorption were studied by central composite design (CCD). The results showed that the highest removal efficiency of lead and zinc (93.13% and 89.04%, respectively) was obtained at pH = 5.49, adsorbent amount: 0.03 g, and contact time: 19.92 min. Besides, the equilibrium and kinetic studies showed that the Langmuir isotherm model (qmax: 245.71 and 199.47 mg g−1 for copper and zinc, respectively) and the pseudo-second-order kinetic model could better determine the sorption process of lead and zinc by the corn silk/sepiolite composite than other models. Also, the thermodynamic study indicated that the sorption process was endothermic. [ABSTRACT FROM AUTHOR]

LIBS is an analytical technique for direct analysis, capable of performing elemental, molecular and isotopic characterization. This technique involves the physical processes of ablation and plasma formation by the incidence of high-energy laser pulses. The direct analysis of liquid samples is challenging due to the occurrence of splashes that impairs the measurement in many aspects. In this work, an inorganic solid substrate consisting of a bentonite/sepiolite composite (70/30 wt%) is described as a support for organic liquids in molecular LIBS analysis. The substrate allowed molecular LIBS measurements of solvents, fuels and even aqueous solution with minimal spectral interference and made it possible to identify molecular radical emissions (CN and C2). Therefore, the proposed substrate is believed to be an alternative material for sampling organic liquids for molecular LIBS analyses. [ABSTRACT FROM AUTHOR]

This work presents a facile hydrothermal synthesis method for fabricating a multifunctional composite of copper zinc tin sulfide (CZTS) nanoparticles coated onto sepiolite fibers. Morphological analysis confirms the firm attachment of approximately 10 nm CZTS nanoparticles onto the sepiolite surface. Elemental analysis verifies the presence of constituent elements from both CZTS and sepiolite, with a slight deficiency in Cu and an abundance of Zn observed. The compositional formula of CZTS in the composite is estimated as Cu1.93Zn1.05Sn0.98S4.04. Notably, the material exhibits a narrow band gap of 1.5 eV, enabling effective utilization of the entire visible light spectrum, making it promising for photocatalytic applications. BET nitrogen adsorption/desorption measurements reveal a substantial surface area of approximately 85.720 m²/g, confirming the composite's versatility and applicability, particularly in photocatalysis and adsorption processes. Additionally, X-ray diffraction analysis indicates reflections consistent with the crystal structures of kasterite CZTS and sepiolite, further confirming the composite's composition. The multifunctional CZTS/Sepiolite composite demonstrates exceptional potential for simultaneous photocatalytic degradation and adsorption of organic pollutants, presenting a promising avenue for sustainable water treatment applications. [ABSTRACT FROM AUTHOR]

The types, occurrence and composition of authigenic clay minerals in argillaceous limestone of sepiolite-bearing strata of the first member of the Middle Permian Maokou Formation (Mao-1 Member) in eastern Sichuan Basin were investigated through outcrop section measurement, core observation, thin section identification, argon ion polishing, X-ray diffraction, scanning electron microscope, energy spectrum analysis and laser ablation-inductively coupled plasma-mass spectrometry. The diagenetic evolution sequence of clay minerals was clarified, and the sedimentary-diagenetic evolution model of clay minerals was established. The results show that authigenic sepiolite minerals were precipitated in the Si4+ and Mg2+-rich cool aragonite sea and sepiolite-bearing strata were formed in the Mao-1 Member. During burial diagenesis, authigenic clay minerals undergo two possible evolution sequences. First, from the early diagenetic stage A to the middle diagenetic stage A1, the sepiolite kept stable in the shallow-buried environment lack of Al3+. It began to transform into stevensite in the middle diagenetic stage A2, and then evolved into disordered talc in the middle diagenetic stage B1 and finally into talc in the period from the middle diagenetic stage B2 to the late diagenetic stage. Thus, the primary diagenetic evolution sequence of authigenic clay minerals, i.e. sepiolite-stevensite-disordered talc-talc, was formed in the Mao-1 Member. Second, in the early diagenetic stage A, as Al3+ carried by the storm and upwelling currents was involved in the diagenetic process, trace of sepiolite started to evolve into smectite, and a part of smectite turned into chlorite. From the early diagenetic stage B to the middle diagenesis stage A1, a part of smectite evolved to illite/smectite mixed layer (I/S). The I/S evolved initially into illite from the middle diagenesis stage A2 to the middle diagenesis stage B2, and then totally into illite in the late diagenesis stage. Thus, the secondary diagenetic evolution sequence of authigenic clay minerals, i.e. sepiolite-smectite-chlorite/illite, was formed in the Mao-1 Member. The types and evolution of authigenic clay minerals in argillaceous limestone of sepiolite-bearing strata are significant for petroleum geology in two aspects. First, sepiolite can adsorb and accumulate a large amount of organic matters, thereby effectively improving the quality and hydrocarbon generation potential of the source rocks of the Mao-1 Member. Second, the evolution from sepiolite to talc is accompanied by the formation of numerous organic matter pores and clay shrinkage pores/fractures, as well as the releasing of the Mg2+-rich diagenetic fluid, which allows for the dolomitization of limestone within or around the sag. As a result, the new assemblages of self-generation and self-accumulation, and lower/side source and upper/lateral reservoir, are created in the Middle Permian, enhancing the hydrocarbon accumulation efficiency. [ABSTRACT FROM AUTHOR]

Low-sulfonation-level polyether sulfone octyl sulfonamide (LSPSO) was blended with a layered double hydroxides (LDHs, Mg2AlCl)/sepiolite nanostructure clay as a filler to create an electrolyte membrane for fuel cell applications. Comprehensive characterization of the composite membranes was conducted, encompassing Fourier-transform infrared spectroscopy, X-ray diffraction, mechanical stability assessment, thermal gravimetric analysis, ion exchange capability, swelling characteristics, water uptake performance, and electrochemical impedance spectroscopy analysis. In comparison to the pristine LSPSO membrane, the presence of LDHs/sepiolite nanoarchitecture material within LSPSO exhibited superior water retention and proton conductivity values, especially at elevated temperatures. The proton conductivity of the composite membranes reached approximately 250 mS/cm, while the unmodified LSPSO membrane only achieved 35 mS/cm at 100 °C. Moreover, LSPSO composite membranes demonstrated enhanced chemical and thermal stability along with higher proton conductivity when compared to pristine LSPSO membranes. These findings highlight the potential of developing tailored LSPSO composite membranes to advance the prospects of commercial applications in proton exchange membrane fuel cells. [ABSTRACT FROM AUTHOR]

Hydrogen production via ethanol steam reforming (ESR) was conducted over amorphous sepiolite (SEP) supported Co based catalysts, deeming as a green and sustainable strategy for renewable energy. However, the subtle regulation to the ESR reactivity of Co/SEP catalysts still remains a challenge. Given the structure sensitive property of ESR, calcination temperature, as a vital regulation parameter, was used to control the key physicochemical properties of catalysts. By various characterization techniques, the results revealed that a calcination temperature mediated metal-support interaction was manifested in the form of Co speciation evolution. With increasing calcination temperature, the occurrence states of Co species change from Co oxides to Co-phyllosilicate then to Co-Al spinel. The ESR experiments indicated that Co/SEP-600 catalyst possessed a suboptimal activity via a dehydrogenation route and a 50 h stability due to a compromising among Co-phyllosilicate dominated MSI, texture, Co0 nanoparticle size and acid-base property. The further improvement of calcination temperature only brought about a poor stability of Co/SEP-700 with a phase transformation or a low activity of Co/SEP-800 with an irreducible Co-Al spinel. Hence, the interaction type of Co with SEP framework Si/Al atoms determined the ESR reactivity of the catalysts, which was modulated by the calcination temperature. Additionally, abundant graphitic coke deposition on the agglomerated Co0 grains was attributed the weak MSI, such as Co/SEP-400, while a slight coke deposition appeared at Co/SEP-800 with an irreducible Co-Al spinel phase. [Display omitted] • Calcination mediated Co speciation was elaborated to adjust H 2 yield from ESR over Co/SEP. • Co speciation evolved from Co oxides to Co-phyllosilicate and then to Co-Al spinel. • The Co-phyllosilicate facilitated ESR behavior due to the texture, MSI and nanoparticle size. • 700 °C heating treatment propelled catalyst degeneration derived from irreducible Co-Al spinel. [ABSTRACT FROM AUTHOR]

In this study, nanocomposite-modified bitumens were prepared and mechanically tested as an alternative to polymer-modified binder. Halloysite nanotube and sepiolite nanoclay were employed along with some polymers to form nanocomposites through the melt intercalation method. The storage stability of the nanocomposite-modified bitumens was tested to evaluate the compatibility. Conventional tests were conducted to compare the physical changes after nanocomposite modification. The viscosity of the nanocomposite-modified binders was determined using a rotational viscometer. Finally, the high- and low-temperature performance grades were evaluated using a rheological testing program. The results showed that the compatibility of the nanocomposites was within acceptable limits, while certain nanocomposite types significantly increased the stiffness of bitumen compared to polymer modifiers alone, resulting in an improvement in the physical performance of bitumen. [ABSTRACT FROM AUTHOR]

Effective and stable catalysts toward ethanol oxidation reaction (EOR) is very important for the application of direct ethanol fuel cells (DEFCs). This research reports a facile synthesis of Ni/sepiolite (Ni/SEP) catalyst through incipient wetness impregnation method, which has large amount of active sites and excellent electrochemical activity toward EOR. Through scanning electron microscope with energy dispersive spectroscopy (SEM-EDS), nickel was found to distribute evenly on the fiber structure of sepiolite through ion exchange with the element magnesium without altering the main structure. With a geometric surface area of 0.07 cm2, Ni/SEP had a larger electrochemical surface area 0.44 m2 g−1, lower onset potential of 0.28 V (vs. SCE), higher peak current density (258.5 mA cm−2), and smaller Tafel slope (20 mV dec−1), indicating a superior electrochemical activity toward EOR. Within the experimental conditions, it was observed to be a diffusion-controlled process based on the linear relationship between peak current and root of scan rates, and the reaction could be accelerated by the increase of both C2H5OH and KOH concentrations. Through the study of cyclic voltammetry as well as calculation of apparent activation energy, an electrolytic-chemical (EC) reaction mechanism was suggested with high valence Ni species as the electron transfer carrier. [ABSTRACT FROM AUTHOR]

To assess whether life existed on Mars, it is crucial to identify geochemical biosignatures that are relevant to specific Martian environments. In this paper, thermochemical modeling was used to investigate fluid chemistries and secondary minerals that would have evolved biotically over geological time scales in Martian fluvio‐lacustrine and evaporitic settings, and that could be used as potential inorganic biosignatures for life detection on Mars. Modeling was performed using fluid and rock chemistries relevant to Gale crater aqueous environments. Potential inorganic biosignatures were identified investigating alteration deposits found at the surface of a simulant exposed to short‐term bio‐mediated weathering and comparing experimental and modeling results. In a fluvio‐lacustrine setting (water/rock of 2000–278), models suggest that less complex mineral assemblages form during biotic basalt dissolution and subsequent brine evaporation compared to what would happen in an abiotic system. Mainly nontronite, kaolinite, and quartz form under biotic conditions, whereas celadonite, talc, and goethite would also precipitate abiotically. Quartz, sepiolite, and gypsum would precipitate from the evaporation of fluids evolved biotically, whereas nontronite, talc, zeolite, and gypsum would form in an abiotic evaporitic environment. These results could be used to distinguish products of abiotic and biotic processes, aiding the interpretation of data from Mars exploration missions. [ABSTRACT FROM AUTHOR]

This study aims to examine the physicochemical and radiological properties of some inorganic materials which are perlite, vermiculite, pumice, rock wool, zeolite, expanded clay aggregate, volcanic tuff, and sepiolite used in soilless agriculture. Water saturation, pH, electrical conductivity, calcium carbonate equivalent, available potassium, available phosphorus, and organic matter analyses were implemented for inorganic materials. The elemental contents of the components for studied inorganic materials were obtained using inductively coupled plasma‐optical emission spectrometry (ICP‐OES). Furthermore, natural and artificial radionuclides of studied inorganic materials were calculated using gamma‐ray spectrometry. The pumice has the highest 226Ra activity concentration, and the zeolite has the highest 232Th and 40K activity concentrations. The 137Cs activity concentration is the maximum for perlite and it is the minimum for expanded clay aggregate. The zeolite has the highest radiological hazard parameters whereas those are the smallest for the rock wool. The Fe, Na, B, Ca, K, Si, P, S, and Mn are the primary components of the inorganic materials used in soilless agriculture. Consequently, this study is contributed to environmental and health problems of livings. In the future, transferred radionuclides from plant to livings assessment can be carried out for these inorganic materials used in soilless agriculture. [ABSTRACT FROM AUTHOR]

Sepiolite is a silicate mineral that improves the fire properties in solid wood when mixed with a water-based coating. The present study was carried out to investigate and evaluate the effects of sepiolite addition to acrylic-latex paint on the pull-off adhesion strength, as an important characteristic of paints and finishes used in the modern furniture industry and historical furniture as well for preservation and restoration of heritage objects. Sepiolite was added at the rate of 10%, and brushed onto plain-sawn beech (Fagus orientalis L.) wood specimens, unimpregnated and impregnated with a 400 ppm silver nano-suspension, which were further thermally modified at 185 °C for 4 h. The results showed that thermal modification had a decreasing effect on the pull-off adhesion strength, primarily as a result of the thermal degradation of cell-wall polymers (mostly hemicelluloses). Still, a decreased wettability as a result of condensation and plasticization of lignin was also partially influential. Based on the obtained results,thermal modification was found to have a significant influence on pull-off adhesion strength. Sepiolite addition had a decreasing effectin all treatments, though the effect was not statistically significant in all treatments. The maximum and minimum decreases due to sepiolite addition were observed in the unimpregnated control (21%) and the thermally-modified NS-impregnated (4%) specimens. Other aspects of the sepiolite addition, and further studies that cover different types of paints and coatings, should be evaluated before coming to a final firm conclusion in this regard. [ABSTRACT FROM AUTHOR]

In this work, a novel silicone composite with low smoke, high flame retardancy, and good overall mechanical properties was prepared, and the flame-retardant mechanism of sepiolite was explored by studying the application of magnesium hydroxide/melamine/starch/sepiolite system in silicone rubber. The impact of the dosage of sepiolite on the mechanical performances of SR composites was studied. The results showed that when the dosage of sepiolite was 20 phr, the comprehensive mechanical performances of the SR composite were the best. The flame-retardant performances of the specimens were characterized by vertical combustion, the limiting oxygen index, and CCT. With the increase of sepiolite dosage, the limiting oxygen index and vertical combustion of the composites gradually enhanced, the highest peak values of HRR and SPR gradually decreased, and the values of THR and TSP gradually reduced. The SEM pictures of the char residue of CCT showed that the char layer formed by the composites with sepiolite had fewer cracks and a more robust structure. The results of the Shore OO hardness test showed that the addition of sepiolite significantly improved the strength of the char residue. TGA analysis indicated that the thermal stability of silicone rubber with sepiolite was enhanced. [ABSTRACT FROM AUTHOR]

The soil in a lead–zinc mining area, contaminated with heavy metals like cadmium (Cd) and lead (Pb), poses a risk to crops such as maize. Experiments using biochar and sepiolite as soil ameliorants in potted maize showed these substances can mitigate heavy metal contamination. Biochar increased potassium and phosphorus in the soil and maize, while sepiolite significantly boosted overground phosphorus by 73.2%. Both ameliorants transformed Cd and Pb into a more stable state in the soil, reducing their accumulation in maize, especially with biochar, which effectively inhibited metal migration during leaching events. This study provided insights for further improvement of soil amendments and multi-factor application experiments. [ABSTRACT FROM AUTHOR]

In this study, a series of polyethylene glycol (PEG)/hydrochloric acid-modified sepiolite (HSEP) composite phase change materials (PCMs) are fabricated via vacuum impregnation. HSEP exhibits high adsorption capacity, rendering it superior to natural sepiolite as carriers for PEG. The resulting composite PCMs possess a melting enthalpy of up to 88.9 J/g and maintain stable thermal performances and chemical structures over 100 heating–cooling cycles between room temperature and 65 °C, thus, indicating long-term reliability. Calorimetry studies on cement paste containing 30% composite PCMs reveal a 24.14% reduction in 3-day cumulative hydration heat. However, the mechanical strength and thermal conductivity of the cement paste are adversely affected. Hence, carbon fibers (CFs) are introduced as reinforcement, resulting in a 28-day compressive strength of 45.6 MPa for cement paste containing 20% composite PCMs and 0.6% CFs. The fabricated composite PCMs are promising functional materials for hydration heat control and energy storage in concrete structures. [ABSTRACT FROM AUTHOR]

Background: Cadmium (Cd) pollution in agricultural soils has become a priority environmental concern globally. A reasonable application of passivators is critical to address the problem. In this study, we examined the remediation effects of rice husk biochar (rBC) and sepiolite (Sep) as single and combined (rBC + Sep) treatments on Cd pollution in a weakly alkaline soil using three maize cultivars (Liyu 16, Zhengdan 958, and Sanbei 218) as test crops. We also explained the mechanisms involved in the remediation effects. Results: The pseudo-second-order kinetic equation and Langmuir model could well describe the adsorption process of rBC + Sep for Cd2+. Compared with the control treatment (CK), soil available Cd concentration decreased by 29.51–36.34% under rBC + Sep treatment (p< 0.05) and the Cd concentrations in maize grains of Liyu 16, Zhengdan 958, and Sanbei 218 decreased by 38.08–47.85%, 37.25–45.61%, and 33.96–46.15%, respectively (p< 0.05). Following passivation treatment, soil available Cd concentration decreased and gradually changed from the exchangeable and carbonate binding forms to the Fe/Mn oxide and residual forms. The bioconcentration factors of Liyu 16 (0.05–0.09) and Sanbei 218 (0.05–0.09) were lower than those of Zhengdan 958 (0.07–0.13). In addition, rBC +Sep treatment increased soil pH and soil electrical conductivity, but the differences were not significant (p> 0.05). Conclusions: The application of 0.2% rBC + 0.5% Sep composite passivation material to weakly alkaline Cd-contaminated soil can effectively reduce the Cd concentration of soil and maize. [ABSTRACT FROM AUTHOR]

A 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO)-based derivative (PN-DOPO) combined with aluminium phosphates-coated sepiolite (Sep@AlPO4) was used to improve the flame retardance, thermal stability and mechanical performances of poly (ethylene oxide) (PEO)/poly (butylene adipate-co-terephthalate) (PBAT) blends. The synergistic effects of PN-DOPO and Sep@AlPO4 on flame-retarded PEO/PBAT composites were systematically discussed. Results indicated that introducing 5 wt% Sep@AlPO4 with 10 wt% PN-DOPO into PEO/PBAT achieved a V-1 rating for the UL-94 test and increased the limiting oxygen index value to 23.7%. Moreover, the peak heat release rate (p-HRR), average HRR and total heat release values of PEO/PBAT/PN10%/Sep5% composites decreased by 35.6%, 11.0% and 23.0% compared with those of PEO/PBAT, respectively. Thermogravimetric analysis (TGA) results confirmed that PN-DOPO/Sep@AlPO4 enhanced the initial thermal stability and char yield of PEO/PBAT matrix, and TGA/Fourier transform infrared spectrometry results revealed that the composites exhibited the characteristic absorption peaks of phosphorous-containing groups and an increase in gas-phase volatiles during thermal degradation. The morphological structures of the residues indicated that PN-DOPO and Sep@AlPO4 mixtures produced a more dense and continuous char layer on the composite surface during burning. Rheological behaviour revealed that higher complex viscosity and modulus values of PEO/PBAT/PN-DOPO/Sep@AlPO4 sample could also promote the crosslinking network structure of condensed phases during combustion. Furthermore, the PEO/PBAT/PN-DOPO/Sep@AlPO4 composites exhibited superior elongation at break and flexural performance than the PEO/PBAT system. All results demonstrated that the PEO/PBAT system modified with PN-DOPO/Sep@AlPO4 showed remarkable flame retardance, and improved thermal stability and mechanical properties, indicating its potential application in areas requiring fire safety. [ABSTRACT FROM AUTHOR]

This study focused on the catalytic pyrolysis of Paulownia (P. elongota) wood. The effects of ZSM-5, Na2CO3, sepiolite, and catalyst ratio (10-80% by wood weight) on product yields and bio-oil composition were investigated. In pyrolysis experiments, 500°C pyrolysis temperature, 50°C min-1 heating rate, and 100 mL min-1 N2 flow rate were kept as constant. The catalyst type and catalyst ratio changed the product yields and bio-oil compositions. Pyrolysis conversion was increased for all catalyst types. Maximum liquid product yields were obtained as 63.26 wt%, 56.18 wt%, and 54.59 wt% with the ZSM-5, Na2CO3 and sepiolite, respectively, at 10 wt% catalyst ratio. For all catalysts, it was determined that the liquid and solid yields reduce and the gas product yield rises with the catalyst ratio. The bio-oil characterization was performed with elemental analysis, FTIR, 1 HNMR, and GC-MS techniques. The bio-oil composition was determined to consist of alkanes, carboxylic acids, ketones, esters, benzenes, and phenols [ABSTRACT FROM AUTHOR]

In this study, two different types of enzyme immobilization methods which were physical adsorptions (PA), and covalent bonding of cross-linked enzyme aggregates (CLEA) were used for laccase to immobilize onto raw polysulfone (PSF) and polysulfone/sepiolite (PSF/SEP) nanocomposites. After the preliminary study, a strategy for screening and optimization of laccase immobilization on PSF/SEP was then further developed by using a two-level factorial design and Box-Behnken design (BBD), respectively. Laccase (Lac) concentration, glutaraldehyde (Gla) concentration, pH values, adsorption (PA) time, PA temperature, CLEA time, and CLEA temperature were chosen in this study as important variables which they will influence the immobilization yield. It was found that Lac concentration, PA time, and Gla concentration are significant variables for the immobilization yield of Lac on PSF/SEP in the screening process. The highest immobilization yield was 75 % at 0.10 mg/mL Lac concentration, 2 h PA time, and 0.20 (v/v) % Gla concentrations, with an increase of 46.57 % over the immobilization yield before optimization. [ABSTRACT FROM AUTHOR]

Magnetic nanoarchitectures have been used to introduce multifunctionality in biopolymeric matrices. Bionanocomposite foams based on the corn protein zein were prepared for the first time using the hydrophobic properties of zein in a sequential treatment consisting of the removal of ethanol-soluble fractions, followed by the water swelling of the remaining phase and a further freeze-drying process. When this protocol is applied to zein pellets, they can be consolidated as porous monoliths. Moreover, it is possible to incorporate diverse types of inorganic nanoparticles in the starting pellet to produce the bionanocomposite foams. In particular, the preparation of superparamagnetic foams has been explored using two approaches: the direct incorporation of magnetite nanoparticles in a ferrofluid by impregnation in the foams, and the application of the foaming process to mixtures of zein with magnetite nanoparticles alone or previously assembled into sepiolite clay fibers. The first methodology leads to the production of inhomogeneous foams, while the use of magnetite nanoparticles and better Fe3O4-sepiolite nanoarchitectured materials as fillers results in more homogeneous materials with improved water stability and mechanical properties, offering superparamagnetic behavior. The resulting multifunctional foams have been tested in adsorption processes using the herbicide 4-chloro-2-methylphenoxyacetic acid as a model pollutant, confirming their potential utility in decontamination applications in open waters as they can be easily recovered from the aqueous medium using a magnet. [ABSTRACT FROM AUTHOR]

The properties of nanocomposites are directly affected by the filler–matrix interaction and therefore surface filler modification is often necessary to improve the mechanical properties of nanocomposites. Our study evaluated surface modification of sepiolite (SEP) on properties of poly(butylene adipate‐co‐terephthalate) (PBAT)‐based nanocomposites. The nanofillers were modified using two organic modifiers, octadecyl isocyanate (OI), and 3‐aminopropyltriethoxysilane (APTES). OI showed higher treatment efficiency than APTES and better results in alkyl groups on the surface of the nanofiller, with crystalline profile, which remained in the nanocomposites. The effect of organo‐sepiolites on the properties of PBAT nanocomposites was investigated by DSC, XRD, TGA, FTIR, scanning electron microscopy (SEM), and mechanical tensile tests. TGA analysis showed that the addition of O‐SEP on PBAT decreases its thermal stability. SEM analysis showed cavities and fiber tips in the matrix associated with clay agglomerates and some untreated clay faces, which impair filler‐matrix interfacial adhesion. Both treatments increased the elastic modulus and preserved the elongation and tensile strength of PBAT and the treatment with OI results in a higher modulus. Although some studies to improve the clay dispersion are necessary, the promising results reveal the potential of using OI and APTES as SEP modifiers to reinforce PBAT or other polyesters. [ABSTRACT FROM AUTHOR]

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of the mixture of Sepiolite and Kieselguhr (diatomaceous earth) (Anpro) as a technological feed additive for all terrestrial animal species. According to the conventional risk assessment, due to lack of adequate data, the safety of the additive Anpro for the target species cannot be established. Based on current knowledge, there is no indication of substantial absorption of the components of the additive and therefore no concern for the consumer. The additive poses a risk by inhalation. It is not irritant to the skin or eyes but should be considered as skin sensitiser. As no suitable data in line with the requirements of the Guidance on risk assessment of nanomaterials were provided by the applicant, the potential risks associated with the presence of nanoparticles could not be assessed for the target species, the consumer and the user. The additive is safe for the environment. The FEEDAP Panel is not in the position to conclude on the efficacy of the additive for all terrestrial animal species. [ABSTRACT FROM AUTHOR]

Acid treatment of sepiolite under different molarity of HCl at various times was studied to find the best acid treatment conditions for obtaining anhydrous sepiolite without structural folding and with fully open and empty channels. It was found that high molarity (e.g., 3 M) acid treatment causes severe acid attack and heterogeneous magnesium dissolution from sepiolite particles. In contrast, the low molarity (e.g., 0.5 M) acid treatment dissolves magnesium homogeneously through the particles. This, in turn, affects the behavior of sepiolite upon calcination at 450ºC in that homogeneous magnesium dissolution gives better structural stability and consequently higher amount of open channels with the least amount of magnesium removal (25%). This is verified by rehydration behavior and specific surface area measurements after the calcination, where over 90% of the surface area could be preserved after the calcination of the low molarity acid-treated samples. No change in the morphology of sepiolite fibers was observed after acid treatment. [ABSTRACT FROM AUTHOR]

The associated impurities with sepiolite, mainly palygorskite, quartz, and dolomite, reduce the industrial quality of this mineral. The objectives of this study were to i) investigate the efficiency of particle size separation for purifying sepiolite and ii) determine the kinetic dissolution of sepiolite in HCl and sodium acetate - acetic acid buffer (SAB). Bulk sepiolite was provided from a mine located around the city of Fairman, in northeastern Iran. Three particle size fractions of 20-50, <20. and <2 μm were separated from the bulk sepiolite. The XRD results showed that the particle size separation method has a great impact on reducing the amount of quartz as well as the complete elimination of dolomite in particles <2 μm and palygorskite in 20-50 μm fractions. The <20 μm fraction composed ~70% of the sample which it's impurities considerably decreased; Therefore, it is a cost-effective fraction for industrial use. Therefore, it is a simple and low-cost physical procedure, without applying chemical reagents to achieve suitable purified sepiolite. The results of dissolution kinetic showed that the data had the best fit with the rate equation of Kt=[(1-(1-X)1/2)²]. Increasing acid concentration, temperature, and time had a direct relation, while the solid to liquid ratio had an inverse relation with the apparent rate constant. This trend was observed for SAB, too. Dissolution of sepiolite in HCl was higher than that of SAB. Acid concentration and temperature were the most effective factors on sepiolite dissolution. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Polytechnic is the property of Journal of Polytechnic 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.)

When drilling into a reservoir, the drilling fluid containing bentonite is prone to solid phase invasion, causing serious damage to the reservoir, and the conventional API barite suspension stability is poor, which makes it easy to cause sedimentation and blockage. Therefore, in order to avoid accidents, we use ultrafine barite to obtain a good suspension stability. More importantly, the method of modifying zwitterionic polymers on the surface of nano-silica is used to develop a temperature-resistant and salt-resistant fluid loss reducer FATG with a core-shell structure, and it is applied to ultra-fine clay-free water-based drilling fluid (WBDF). The results show that the filtration loss of clay-free drilling fluid containing FATG can be reduced to 8.2 mL, and AV can be reduced to 22 mPa·s. Although the viscosity is reduced, FATG can reduce the filter loss by forming a dense mud cake. The clay-free drilling fluid system obtained by further adding sepiolite can reduce the filtration loss to 3.8 mL. After aging at 220 °C for 15 d, it still has significant salt tolerance, the filtration loss is only 9 mL, the viscosity does not change much, a thinner and denser mud cake is formed, and the viscosity coefficient of the mud cake is smaller. The linear expansion test and permeability recovery evaluation were carried out. The hydration expansion inhibition rate of bentonite can reach 72.5%, and the permeability recovery rate can reach 77.9%, which can meet the long-term drilling fluid circulation work in the actual drilling process. This study can provide guidance for technical research in related fields such as reservoir protection. [ABSTRACT FROM AUTHOR]