A simple synthetic approach for the preparation of graphene-diatom silica composites in the form of self-assembled aerogels with three-dimensional networks from natural graphite and diatomite rocks ...is demonstrated for the first time. Their adsorption performance for the removal of mercury from water was studied as a function of contact time, solution pH, and mercury concentration to optimize the reaction conditions. The adsorption isotherm of mercury fitted well with the Langmuir model, representing a very high adsorption capacity of >500 mg of mercury/g of adsorbent. The prepared aerogels exhibited outstanding adsorption performance for the removal of mercury from water, which is significant for environmental applications.
The development of microcracks in recycled aggregate concrete (RAC) directly impacts its durability; hence, these cracks need to be treated. The authors propose bacterial self-healing by introducing ...Bacillus megaterium strains into 50% and 100% RAC mixes to heal cracks in RAC on their own. A protective bacterial carrier is needed to protect the bacteria in the high-pH environment of concrete and in a dense microstructure so that the CaCO3 production capacity of the bacteria is not affected. For this purpose, diatomaceous earth (DE) and reused concrete aggregate (RCA) were investigated in this study as potential carriers for the immobilization of bacterial spores that heal cracks in RAC on their own. Filling of surface cracks, the self-healing ratio within concrete, recovery of compressive strength, and water impermeability were examined to test self-healing, and were compared with those of samples containing directly inserted bacteria. Cracks with a maximum width of 0.47, 0.50, and 0.55 mm were completely filled in the specimens containing directly inserted bacteria, immobilized bacteria in RCA, and immobilized bacteria in DE, respectively. Specimens containing bacteria immobilized in DE and RCA had better self-healing performance in terms of recovery of concrete properties and self-healing ratio within concrete than did specimens containing bacteria directly added. Additionally, specimens containing bacteria immobilized in DE exhibited better self-healing results in precracked specimens up to 56 days of age, whereas self-healing by bacteria immobilized in RCA was found to be more effective in precracked specimens at 120 days of age. Overall, it was concluded that DE and RCA can be used as carriers for bacterial immobilization in self-healing RAC, which would not only maintain the durability of RAC but also increase its service life.
Inorganic diatomite nanoparticles (DNPs) have gained increasing interest as drug delivery systems due to their porous structure, long half-life, thermal and chemical stability. Gold nanoparticles ...(AuNPs) provide DNPs with intriguing optical features that can be engineered and optimized for sensing and drug delivery applications. In this work, we combine DNPs with gelatin stabilized AuNPs for the development of an optical platform for Galunisertib delivery. To improve the DNP loading capacity, the hybrid platform is capped with gelatin shells of increasing thicknesses. Here, for the first time, full optical modeling of the hybrid system is proposed to monitor both the gelatin generation, degradation, and consequent Galunisertib release by simple spectroscopic measurements. Indeed, the shell thickness is optically estimated as a function of the polymer concentration by exploiting the localized surface plasmon resonance shifts of AuNPs. We simultaneously prove the enhancement of the drug loading capacity of DNPs and that the theoretical modeling represents an efficient predictive tool to design polymer-coated nanocarriers.
This study proposes the use of diatomaceous earth (DE) as a surface-treating agent for recycled aggregate (RA) to enhance the performance of recycled aggregate concrete (RAC). The treatment process ...involves pre-saturating the RA and applying a coating using a slurry composed of calcined DE and ordinary Portland cement at specific proportions. Test results demonstrate that the compressive and splitting tensile strengths of RAC can be significantly improved, with increases of up to 20.0% and 36.0% respectively. Additionally, the 28-day chloride diffusion coefficient of RAC can be reduced by up to 32.0% by adjusting the proportion of DE in the slurry. These improvements are not influenced by changes in the quality of the RA, but rather by the enhanced interfacial transition zone (ITZ) in RAC. Microscopic measurements of the ITZ reveal a layered structure resulting from the surface treatment, characterized by lower porosity and higher microhardness compared to the reference RAC. This enhanced ITZ is primarily responsible for the improved macro-scale performance of RAC. The findings of this study confirm the feasibility of using DE as a surface-treating agent for RA to produce RAC with enhanced strength and durability. Furthermore, it suggests the promising use of DE in the construction industry, avoiding the drawbacks associated with using high-dosage DE that can impact concrete consistency and water demand.
Improving the sulfur content and cycling performance of the cathode is the key to the commercial application of lithium-sulfur batteries. Herein, the diatomite-derived nitrogen-doped carbon aerogel ...provides an ample sulfur loading space that can be loaded with 98% sublimated sulfur. The Li-S battery delivered an initial discharge capacity of 703.1 mAh g
−1
and still retained 510.1 mAh g
−1
at 0.5C after 200 cycles, which is attributed to the highly disordered carbon and catalytic activity.
The ultralight carbon material with diatomite as template can drive 98 wt% sulfur material with only 2 wt%, and it still has high performance when used as the cathode material for lithium sulfur batteries.
AbstractCracks in cement-based materials are one of the main factors affecting the durability of structure. Recent research in the field of concrete materials showed that self-healing in cement-based ...systems can be achieved by triggering biogenic calcium carbonate (CaCO3) precipitation. The goal of this study is to establish a comparative evaluation of the use of sepiolite, bentonite, and diatomaceous earth (DE) as an immobilization barrier of Sporosarcina pasteurii (S. pasteurii) cells to trigger self-healing in cement-based systems. For the first time in the literature, this study will provide insight into the use of natural minerals, such as bentonite and sepiolite, as protective carriers for vegetative S. pasteurii cells in cement-based materials and present a comparative evaluation of factors influencing crack healing, such as the microstructure and composition of immobilization barriers. A two-phase self-healing bioadditive was obtained by immobilizing vegetative S. pasteurii cell samples on natural porous minerals with or without the use of required nutrients. Then the samples were cracked by a three-point bending test, and the healing process was screened via stereomicroscope imaging and ultrasonic pulse velocity (UPV) testing after subjecting the cracked samples to 28 days of moist curing. Flexural cracks induced in mortar samples were filled with biogenic precipitate. Relatedly, the water absorption capacity of the samples was decreased in mortar samples containing bacterial cells, the nutrients were added in the curing solution. Fourier transform infrared spectroscopy and scanning electron microscopy analyses showed that calcite was the predominant polymorph of CaCO3 sealant in cracks.
Diatomaceous earth (DE), or diatomite silica microparticles originated from fossilized diatoms are a potential substitute for its silica-based synthetic counterparts to address limitations in ...conventional drug delivery. This study presents the impact of engineered surface chemistry of DE microparticles on their drug loading and release properties. Surface modifications with four silanes, including 3-aminopropyltriethoxy silane (APTES), methoxy-poly-(ethylene-glycol)-silane (mPEG-silane), 7-octadecyltrichlorosilane (OTS), 3-(glycidyloxypropyl)trimethoxysilane (GPTMS) and two phosphonic acids, namely 2-carboxyethyl-phosphonic acid (2 CEPA) and 16-phosphono-hexadecanoic acid (16 PHA) were explored in order to tune drug loading and release characteristics of water insoluble (indomethacin) and water soluble drugs (gentamicin). Successful grafting of these functional groups with different interfacial properties was confirmed using X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). Thermogravimetric analysis (TGA) was applied to determine the amount of loaded drugs and UV-spectrophotometry to analyse in vitro drug release from modified DE microparticles. Differences in drug release time (13–26 days) and loading capacity (14–24%) were observed depending on functional groups on the surface of DE microparticles. It was found that hydrophilic surfaces, due to the presence of polar carboxyl, amine or hydrolyzed epoxy group, favor extended release of indomethacin, while the hydrophobic DE surface modified by organic hydrocarbons gives a better sustained release profile for gentamicin. This work demonstrates that by changing surface functionalities on DE microparticles, it is possible to tune their drug loading and release characteristics for both hydrophobic and hydrophilic drugs and therefore achieve optimal drug delivery performance.
This work aims to isolate and detect pesticide (carbendazim) residue in real food samples: orange juice and kale leaves. The combination of on-chip thin layer chromatography (TLC) and surface ...enhanced Raman scattering (SERS) spectroscopy was used for the separating and detecting of carbendazim (MBC) from the complex food sample. In order to achieve on-site detection of MBC from real food sample, the portable Raman spectrometer was coupled with TLC-SERS. The porous stationary phase composed of diatomite biosilica is beneficial for SERS enhancement and eluent migration. The experiments exhibited that the diatomite chip was suitable for TLC separation and has not shown SERS background and provided excellent separation efficiency, 10−8 M silver colloids were appropriate for the SERS measurement on TLC chip. The food sample was directly spotted onto the diatomite chip for TLC separation without any pretreatment. The separation and detection process were finished in less than 5 min, the mixture of pyrimethanil, pymetrozine and MBC could be distinguished simultaneously by TLC-SERS at one diatomite chip. The MBC in orange juice and kale were successfully detected, and a limit of detection (LOD) less than 2 ppm could be achieved.
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•Thin layer diatomite film and Ag nanoparticles were developed as on-chip TLC-SERS sensor.•The diatomite chip could simultaneously separate three kind pesticides from their mixture.•On-site sensing pesticide in orange juice/vegetable is achieved by using TLC-SERS on diatomite chip.
Graphdiyne (GDY), a new kind of two‐dimensional (2D) carbon allotropes, has extraordinary electrical, mechanical, and optical properties, leading to advanced applications in the fields of energy ...storage, photocatalysis, electrochemical catalysis, and sensors. However, almost all reported methods require metallic copper as a substrate, which severely limits their large‐scale application because of the high cost and low specific surface area (SSA) of copper substrate. Here, freestanding three‐dimensional GDY (3DGDY) is successfully prepared using naturally abundant and inexpensive diatomite as template. In addition to the intrinsic properties of GDY, the fabricated 3DGDY exhibits a porous structure and high SSA that enable it to be directly used as a lithium‐ion battery anode material and a 3D scaffold to create Rh@3DGDY composites, which would hold great potential applications in energy storage and catalysts, respectively.
Freestanding three‐dimensional graphidyne (3DGDY) is successfully prepared using naturally abundant and inexpensive diatomite as a template. The fabricated 3DGDY exhibits a porous structure and high specific surface area that enable the 3DGDY to be applied as a potential lithium‐ion battery anode material and an ideal 3D scaffold to create Rh@3DGDY composites with high catalytic and recyclable performance.
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