RESUMEN
For electrochemical application in seawater or brine, continuous scaling on cathodes will form insulation layers, making it nearly impossible to run an electrochemical reaction continuously. Herein, we report our discovery that a cathode consisting of conical nanobundle arrays with hydrophobic surfaces exhibits a unique scaling-free function. The hydrophobic surfaces will be covered with microbubbles created by electrolytic water splitting, which limits scale crystals from standing only on nanotips of conical nanobundles, and the bursting of large bubbles formed by the accumulation of microbubbles will cause a violent disturbance, removing scale crystals automatically from nanotips. Benefiting from the scaling-free properties of the cathode, high-purity nano-CaCO3 (98.9%) and nano-Mg(OH)2 (99.5%) were extracted from seawater. This novel scaling-free cathode is expected to eliminate the inherent limitations of electrochemical technology and open up a new route to seawater mining.
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Carbonato de Calcio , Electrodos , Agua de Mar , Agua de Mar/química , Carbonato de Calcio/química , Hidróxido de Magnesio/química , Técnicas ElectroquímicasRESUMEN
The healing of skin wounds is a continuous and coordinated process, typically accompanied by microbial colonization and growth. This may result in wound infection and subsequent delay in wound healing. Therefore, it is of particular importance to inhibit the growth of microorganisms in the wound environment. In this study, magnesium hydroxide-doped polycaprolactone (PCL/MH) nanofibrous spheres were fabricated by electrospinning and electrospray techniques to investigate their effects on infected wound healing. The prepared PCL/MH nanofibrous spheres had good porous structure and biocompatibility, providing a favorable environment for the delivery and proliferation of adipose stem cells. The incorporation of MH significantly enhanced the antimicrobial properties of the spheres, in particular, the inhibition of the growth of S. aureus and E. coli. We showed that such PCL/MH nanofibrous spheres had good antimicrobial properties and effectively promoted the regeneration of infected wound tissues, which provided a new idea for the clinical treatment of infected wounds.
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Escherichia coli , Hidróxido de Magnesio , Nanofibras , Poliésteres , Piel , Staphylococcus aureus , Cicatrización de Heridas , Cicatrización de Heridas/efectos de los fármacos , Nanofibras/química , Staphylococcus aureus/efectos de los fármacos , Escherichia coli/efectos de los fármacos , Poliésteres/química , Piel/efectos de los fármacos , Piel/microbiología , Piel/lesiones , Animales , Hidróxido de Magnesio/química , Hidróxido de Magnesio/farmacología , Antibacterianos/farmacología , Antibacterianos/química , Antibacterianos/administración & dosificación , Antibacterianos/uso terapéutico , Infección de Heridas/tratamiento farmacológico , Infección de Heridas/microbiología , Humanos , Materiales Biocompatibles/farmacología , Materiales Biocompatibles/química , Andamios del Tejido/químicaRESUMEN
In this work, salicylic acid (SA) was used to induce the self-assembly of octadecyl trimethyl ammonium chloride (OTAC), a cationic surfactant, into three-dimensional wormlike micelle aggregates. These aggregates act as a soft template for hierarchical MgAl hydrotalcite (LDH) to create a multi-level pore structure adsorption material. Scanning electron microscopy characterization showed that the surface of the hierarchical hydrotalcite exhibited a dense layered structure, unlike the monolayer structure of ordinary hydrotalcite. Furthermore, the hierarchical MgAl-LDH possesses a significantly larger specific surface area (113.94 m2/g) and wide pore size distribution ranging more extensively from 2 to 80 nm, which significantly has an impressive adsorption effect on sulfonated lignite (SL), with a maximum adsorption capacity of 192.7 mg/g at pH = 7. Extensive research has been conducted on the adsorption mechanism of hierarchical MgAl-LDH, attributing it to surface adsorption due to the unique multi-level structure of the adsorbent. After two cycles of regeneration experiments, the adsorption capacity of the adsorbent remained at a high level of 179.1 mg/g, demonstrating the excellent renewability of hierarchical MgAl-LDH. Moreover, the hierarchical hydrotalcite showed high adsorption capacity in the adsorption of sulfonated lignite, which was attributed to its larger specific surface area and superior pore structure to expose more active sites.
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Hidróxido de Aluminio , Hidróxido de Magnesio , Hidróxido de Aluminio/química , Hidróxido de Magnesio/química , AdsorciónRESUMEN
Easy synthesis of efficient, non-toxic photocatalysts is a target to expand their potential applications. In this research, the role of Eu3+ doping in the non-toxic, affordable, and easily prepared MgAl hydrotalcite-like compounds (HTlcs) was explored in order to prepare visible light semiconductors. Eu doped MgAl-HTlcs (MA-xEu) samples were prepared using a simple coprecipitation method (water, room temperature and atmospheric pressure) and europium was successfully incorporated into MgAl HTlc frameworks at various concentrations, with x (Eu3+/M3+ percentage) ranging from 2 to 15. Due to the higher ionic radius and lower polarizability of Eu3+ cation, its presence in the metal hydroxide layer induces slight structural distortions, which eventually affect the growth of the particles. The specific surface area also increases with the Eu content. Moreover, the presence of Eu3+ 4f energy levels in the electronic structure enables the absorption of visible light in the doped MA-xEu samples and contributes to efficient electron-hole separation. The microstructural and electronic changes induced by the insertion of Eu enable the preparation of visible light MgAl-based HTlcs photocatalysts for air purification purposes. Specifically, the optimal HTlc photocatalyst showed improved NOx removal efficiency, â¼ 51% (UV-Vis) and 39% (visible light irradiation, 420 nm), with excellent selectivity (> 96 %), stability (> 7 h), and enhanced release of â¢O2- radicals. Such results demonstrate a simple way to design photocatalytic HTlcs suitable for air purification technologies.
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Hidróxido de Aluminio , Europio , Hidróxido de Magnesio , Óxidos de Nitrógeno , Oxidación-Reducción , Europio/química , Catálisis , Hidróxido de Magnesio/química , Hidróxido de Aluminio/química , Óxidos de Nitrógeno/química , Procesos Fotoquímicos , Luz , Contaminantes Atmosféricos/químicaRESUMEN
Layered double hydroxides (LDH) have been shown to be effective adsorbents, but their utility for the treatment of per- and polyfluoroalkyl substances (PFAS) in water has not been fully explored. In this study, the adsorption of 9 PFAS on hydrotalcite (HT), a type of LDH, was investigated using reaction solutions with environmentally relevant PFAS concentrations. The adsorption of individual PFAS by HT depended upon a range of factors, including the temperature used to pre-treat (i.e., calcine) the HT, aging conditions, and the presence of anions in the solution. HT calcined near 400 °C most effectively adsorbed PFAS, but its ability to adsorb PFAS was sensitive to storage conditions. The adsorption of CO2 and moisture from air, which likely resulted in the re-intercalation of CO32- into the interlayer regions of HT, was observed to reduce PFAS adsorption and may explain performance loss over time. The adsorption trend among 9 PFAS and the influence on this process by Cl-, NO3-, SO42-, and CO32- indicated that adsorption occurred via a combination of ion exchange, electrostatic attraction, and hydrophobic interactions, although the relative importance of each mechanism deserves further investigation. During this study, we also demonstrated for the first time that HT can be thermally regenerated at 400 °C without affecting its ability to adsorb PFOS and PFBA. Overall, our results suggest that HT may serve as an effective alternative for PFAS treatment.
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Hidróxido de Aluminio , Fluorocarburos , Hidróxido de Magnesio , Contaminantes Químicos del Agua , Adsorción , Hidróxido de Magnesio/química , Hidróxido de Aluminio/química , Fluorocarburos/química , Contaminantes Químicos del Agua/química , Purificación del Agua/métodos , TemperaturaRESUMEN
Purpose: The committed differentiation fate regulation has been a difficult problem in the fields of stem cell research, evidence showed that nanomaterials could promote the differentiation of stem cells into specific cell types. Layered double hydroxide (LDH) nanoparticles possess the regulation function of stem cell fate, while the underlying mechanism needs to be investigated. In this study, the process of embryonic stem cells (ESCs) differentiate to neural progenitor cells (NPCs) by magnesium aluminum LDH (MgAl-LDH) was investigated. Methods: MgAl-LDH with diameters of 30, 50, and 100 nm were synthesized and characterized, and their effects on the cytotoxicity and differentiation of NPCs were detected in vitro. Dot blot and MeRIP-qPCR were performed to detect the level of m6A RNA methylation in nanoparticles-treated cells. Results: Our work displayed that LDH nanoparticles of three different sizes were biocompatible with NPCs, and the addition of MgAl-LDH could significantly promote the process of ESCs differentiate to NPCs. 100 nm LDH has a stronger effect on promoting NPCs differentiation compared to 30 nm and 50 nm LDH. In addition, dot blot results indicated that the enhanced NPCs differentiation by MgAl-LDH was closely related to m6A RNA methylation process, and the major modification enzyme in LDH controlled NPCs differentiation may be the m6A RNA methyltransferase METTL3. The upregulated METTL3 by LDH increased the m6A level of Sox1 mRNA, enhancing its stability. Conclusion: This work reveals that MgAl-LDH nanoparticles can regulate the differentiation of ESCs into NPCs by increasing m6A RNA methylation modification of Sox1.
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Diferenciación Celular , Nanopartículas , Células-Madre Neurales , Diferenciación Celular/efectos de los fármacos , Animales , Células-Madre Neurales/efectos de los fármacos , Células-Madre Neurales/citología , Células-Madre Neurales/metabolismo , Ratones , Nanopartículas/química , Metilación/efectos de los fármacos , Hidróxidos/química , Hidróxidos/farmacología , Metiltransferasas/metabolismo , Metiltransferasas/genética , Tamaño de la Partícula , Células Madre Embrionarias/efectos de los fármacos , Células Madre Embrionarias/citología , Adenosina/farmacología , Adenosina/química , Adenosina/análogos & derivados , Hidróxido de Aluminio/química , Hidróxido de Aluminio/farmacología , Hidróxido de Magnesio/química , Hidróxido de Magnesio/farmacologíaRESUMEN
The process of removing Ca2+ and Mg2+ ions typically results in the co-precipitation of Ca2+ and Mg2+ along with other salt waste. To improve water treatment efficiency towards a zero-waste goal, it is crucial to separate Ca2+ and Mg2+, and recover them in their purified form. This study proposes a two-step electrochemical approach that separately recovers Ca2+ as CaCO3 and Mg2+ as Mg(OH)2. The first step uses an undivided cell with 3D electrodes and controlled flow directions to selectively precipitate CaCO3 on the electrode, keeping the cell removal efficiency. The second step employs a two-compartment cell with a cationic exchange membrane to recover Mg(OH)2. This approach was evaluated on RO reject water with high Ca2+ to Mg2+ ratio and industrial effluent-polluted groundwater with a low ratio. Treatment of domestic RO reject water using undivided cell specifically recovered 64% of CaCO3, although the low conductivity of the RO reject water limited further Mg2+ recovery. Conversely, treating industrial effluent-polluted groundwater with this two-step process successfully recovered 80% of CaCO3 and 94% of Mg(OH)2. SEM, EDAX, and XRD analysis confirmed the quality of the recovered products.
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Carbonato de Calcio , Técnicas Electroquímicas , Agua Subterránea , Hidróxido de Magnesio , Contaminantes Químicos del Agua , Purificación del Agua , Carbonato de Calcio/química , Agua Subterránea/química , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/química , Purificación del Agua/métodos , Técnicas Electroquímicas/métodos , Hidróxido de Magnesio/química , Magnesio/química , Eliminación de Residuos Líquidos/métodosRESUMEN
Hydrotalcite-silver (HT-Ag) nanoparticles have been involved in various daily crucial applications, such as antibacterial, photocatalytic, adsorption, etc. There are many approaches to synthesizing silver nanoparticles (AgNPs) decorated on hydrotalcite (HT) surface and the most used approach is using a strong reducing agent. Thus, affordable but effective "green" reducing agents - Syzygium nervosum leaf extract, are taken into account in this work to solve several issues related to chemical reducing agents. This work aimed to assess the effect of Syzygium nervosum leaf extract as a reducing agent for green synthesis of AgNPs on HT through an optimizing process using response surface methodology (RSM) and the Box-Benken model. The optimal conditions for the synthesis of AgNPs on HT include a reaction time of 6.15â hours, a reaction temperature of 50 °C, and the ratio of diluted Syzygium nervosum leaf extract to reduce AgNO3 of 50.37â mL/mg. Under the optimal conditions, the yield of the reduction reaction reached 77.54 %, close to the theoretical value of 76.97 %. The optimization model was suitable for the experiment data. Besides, the morphology, density, and characteristics of AgNPs on the surface of HT layers have been determined by using Ultraviolet-visible spectroscopy, Field emission scanning electron microscopy (FESEM), High-resolution transmission electron microscopy (HR-TEM), selected area diffraction, X-ray diffraction, Dynamic light scattering (DLS), Infrared (IR) spectroscopy, Fluorescence emission spectroscopy (FE), Brunauer-Emmett-Teller (BET) methods. The spherical AgNPs were synthesized successfully on the surface of HT with the average particle size of 13.0±1.1â nm. Interestingly, HT-Ag hybrid materials can inhibit strongly the growth of E. coli, S. aureus as well as two antibiotic resistance bacterial strains, P. stutzeri B27, and antibiotic resistance E. coli. Especially, the antibacterial activity quantification and durability of the HT-Ag hybrid materials were also tested. Overall, the HT-Ag hybrid materials are very promising for application in material science and biomedicine fields.
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Hidróxido de Aluminio , Tecnología Química Verde , Hidróxido de Magnesio , Nanopartículas del Metal , Extractos Vegetales , Plata , Syzygium , Plata/química , Nanopartículas del Metal/química , Syzygium/química , Hidróxido de Magnesio/química , Extractos Vegetales/química , Hidróxido de Aluminio/química , Sustancias Reductoras/química , Hojas de la Planta/química , Antibacterianos/química , Antibacterianos/síntesis química , Antibacterianos/farmacología , Tamaño de la Partícula , Pruebas de Sensibilidad Microbiana , Staphylococcus aureus/efectos de los fármacos , Escherichia coli/efectos de los fármacos , Propiedades de SuperficieRESUMEN
Carbon neutral or negative mining can potentially be achieved by integrating carbon mineralization processes into the mine design, operations, and closure plans. Brucite [Mg(OH)2] is a highly reactive mineral present in some ultramafic mine tailings with the potential to be rapidly carbonated and can contain significant amounts of ferrous iron [Fe(II)] substituted for Mg; however, the influence of this substitution on carbon mineralization reaction products and efficiency has not been thoroughly constrained. To better assess the efficiency of carbon storage in brucite-bearing tailings, we performed carbonation experiments using synthetic Fe(II)-substituted brucite (0, 6, 23, and 44 mol % Fe) slurries in oxic and anoxic conditions with 10% CO2. Additionally, the carbonation process was evaluated using different background electrolytes (NaCl, Na2SO4, and Na4SiO4). Our results indicate that carbonation efficiency decreases with increasing Fe(II) substitution. In oxic conditions, precipitation of ferrihydrite [Fe10IIIO14(OH)2] and layered double hydroxides {e.g., pyroaurite [Mg6Fe2III(OH)16CO3·4H2O]} limited carbonation efficiency. Carbonation in anoxic environments led to the formation of Fe(II)-substituted nesquehonite (MgCO3·3H2O) and dypingite [Mg5(CO3)4(OH)2·â¼5H2O], as well as chukanovite [Fe2IICO3(OH)2] in the case of 23 and 44 mol % Fe(II)-brucite carbonation. Carbonation efficiencies were consistent between chloride- and sulfate-rich solutions but declined in the presence of dissolved Si due to the formation of amorphous SiO2·nH2O and Fe-Mg silicates. Overall, our results indicate that carbonation efficiency and the long-term fate of stored CO2 may depend on the amount of substituted Fe(II) in both feedstock minerals and carbonate products.
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Hierro , Hierro/química , Hidróxido de Magnesio/química , Carbono/química , Minería , SolucionesRESUMEN
The rapid transition towards modernization and industrialization led to an increase in urban population, resulting in paramount challenge to municipal sewage sludge management. Anaerobic digestion (AD) serves as a promising venue for energy recovery from waste-activated sludge (WAS). Addressing the challenge of breaking down floc structures and microbial cells is crucial for releasing extracellular polymeric substances and cytoplasmic macromolecules to facilitate hydrolysis and fermentation process. The present study aims to introduce a combined process of alkaline/acid pre-treatments and AD to enhance sludge digestion and biogas production. The study investigates the influence of alkali pretreatment at ambient temperature using four alkali reagents (NaOH, Ca(OH)2, Mg(OH)2, and KOH). The primary goal is to provide insights into the intricate interplay of alkali dosages (0.04-0.12 g/gTS) on key physic-chemical parameters crucial for optimizing the pre-treatment dosage. Under the optimized alkaline/acid pre-treatment condition, the TSS reduction of 18%-30% was achieved. An increase in sCOD concentration (24%-50%) signifies the enhanced hydrolysis and solubilization rate of organic substrate in WAS. Finally, the biomethane potential test (BMPT) was performed for pre-treated WAS samples. The maximum methane (CH4) yield was observed in combination A1 (244 mL/g) and D1 (253 mL/g), demonstrating the pivotal role of alkali optimization in enhancing AD efficiency. This study serves as a valuable resource to policymakers, researchers, and technocrats in addressing challenges associated to sludge management.
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Biocombustibles , Aguas del Alcantarillado , Aguas del Alcantarillado/química , Biocombustibles/análisis , Anaerobiosis , Eliminación de Residuos Líquidos/métodos , Álcalis/química , Metano , Hidróxido de Sodio/química , Hidróxido de Calcio/química , Hidróxido de Magnesio/química , Reactores Biológicos , Hidróxidos/química , Compuestos de Potasio/químicaRESUMEN
This study proposed and examined a new process flowsheet for treating neutral mine drainage (NMD) from an open-pit gold mine. The process consisted of three sequential stages: (1) in situ hydrotalcite (HT) precipitation; (2) low-cost carbon substrate driven microbial sulfate reduction; and (3) ferrosol reactive barrier for removing biogenic dissolved hydrogen sulfide (H2S). For concept validation, laboratory-scale columns were established and operated for a 140-days period with key process performance parameters regularly measured. At the end, solids recovered from various depths of the ferrosol column were analysed for elemental composition and mineral phases. Prokaryotic microbial communities in various process locations were characterised using 16S rRNA gene sequencing. Results showed that the Stage 1 HT-treatment substantially removed a range of elements (As, B, Ba, Ca, F, Zn, Si, and U) in the NMD, but not nitrate or sulfate. The Stage 2 sulfate reducing bioreactor (SRB) packed with 70 % (v/v) Eucalyptus woodchip, 1 % (w/v) ground (<1 mm) dried Typha biomass, and 10 % (w/v) NMD-pond sediment facilitated complete nitrate removal and stable sulfate removal of ca. 50 % (50 g-SO4 m-3 d-1), with an average H2S generation rate of 10 g-H2S m-3d-1. The H2S-removal performance of the Stage 3 ferrosol column was compared with a synthetic amorphous Fe-oxyhydroxide-amended sand control column. Although both columns facilitated excellent (95-100 %) H2S removal, the control column only enabled a further ca. 10 % sulfate reduction, giving an overall sulfate removal of 56 %. In contrast, the ferrosol enabled an extra 99.9 % sulfate reduction in the SRB effluent, leading to a near complete sulfate removal. Overall, the process successfully eliminated a range of metal/metalloid contaminants, nitrate, sulfate (2500 mg-SO4 L-1 in the NMD to <10 mg-SO4 L-1 in the final effluent) and H2S (>95 % removal). Further optimisation is required to minimise release of ferrous iron from the ferrosol barrier into the final effluent.
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Hidróxido de Aluminio , Sulfuro de Hidrógeno , Hidróxido de Magnesio , ARN Ribosómico 16S , Nitratos , Sulfatos/química , Reactores BiológicosRESUMEN
In order to prevent uranium pollution and recovery uranium resources, it was necessary to find a highly efficient adsorbent for radioactive wastewater treatment. Herein, U(VI) imprinted polyethyleneimine (PEI) incorporated chitosan/layered hydrotalcite composite foam (IPCL) was synthesized by combining ion-imprinting and freeze-drying techniques. IPCL has a high amino/imino content and an ultralight macroporous structure, making it capable of efficiently adsorbing U(VI) and easy to separate; Especially after ion-imprinting, vacancies matching the size of uranyl ions were formed, significantly improving U(VI) selectivity. The adsorption isotherms and adsorption kinetics were in accordance with the Freundlich model and PSO model respectively, indicating that heterogeneous adsorption of U(VI) by the adsorbents. The adsorption capacity of IPCL-2 for U(VI) reached 278.8. mg/g (under the conditions of optimal pH 5.0, temperature of 298 K, contact time of 2 h, and adsorbent dosage of 0.2 g/L), which is almost double of that for the non-imprinted foam (PCL-2, 138.2 mg/g), indicating that IPCL-2 can intelligently recognize U(VI). The heterogeneous adsorption mechanism of U(VI) by IPCL-2 involves complexation, ion-exchange and isomorphic substitution. The adsorption of U(VI) by IPCL-2 is spontaneous and endothermic. IPCL-2 has excellent adsorption performance for U(VI), and is a promising adsorbent for radioactive pollution control.
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Hidróxido de Aluminio , Quitosano , Hidróxido de Magnesio , Polietileneimina , Uranio , Uranio/química , Polietileneimina/química , Quitosano/química , Adsorción , Hidróxido de Aluminio/química , Cinética , Hidróxido de Magnesio/química , Porosidad , Concentración de Iones de Hidrógeno , Purificación del Agua/métodos , Temperatura , Iones/químicaRESUMEN
The utilization of municipal solid waste incineration residues in alkali-activated granulated ground blast furnace slag (GGBFS) has garnered substantial interest for its potential in sustainable solid waste management and achieving a low-carbon footprint. However, incorporating these residues often leads to the deterioration of mechanical properties. This study revealed the role of silica fume (SF) and nano-silica (NS) derived from olivine within a sodium carbonate-activated GGBFS system incorporating air pollution control (APC) residues. The dosage of silica additives and APC residues ranges from 0 - 6 wt% and 0-15 wt%, respectively. The mechanical properties, reaction kinetics, phase composition, microstructure and carbonation resistance of the blended binder were investigated. Results indicated that SF slightly improved the early compressive strength with the formation of C-(A)-S-H gel (Ca/Si = 1.47, Al/Si = 0.23), hemicarboaluminate and hydrotalcite; reactive NS retarded the activation of GGBFS and inhibited the formation of hemicarboaluminate and hydrotalcite, while promoting the formation of C-A-S-H gel (Ca/Si = 1.01, Al/Si = 0.23), resulting in an impressive 80.3 % enhancement in compressive strength. Notably, NS-modified samples exhibited decreased carbonation resistance due to increased porosity and C-(A)-S-H gels that are vulnerable to carbonation. Conversely, 2 % SF addition decreased the diffusion rate of CO2, and APC residues improved the carbonation resistance by facilitating the formation of C-(A)-S-H gel with a higher Ca/Si ratio. This study provided an alternative management practice for APC residues with favorable early strength development and offered new insights into using silica additives to enhance waste-combined alkali-activated materials.
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Contaminación del Aire , Carbonatos , Hidróxido de Magnesio , Dióxido de Silicio , Hidróxido de AluminioRESUMEN
BACKGROUND: Nephrotoxicity remains the most serious side effect of cisplatin therapy. Cisplatin-induced nephrotoxicity (CIN) limits the use of this drug and affects up to 20% of patients. Several possible interventions such as magnesium supplementation may prevent CIN. This study aimed to review different types of hydration protocols and we conducted a meta-analysis of magnesium supplementation to understand its effect in protecting against CIN. METHODS: A search of the PubMed, Embase, and Cochrane databases was performed. Trials were eligible if they enrolled patients who received cisplatin and different hydration protocols to prevent CIN. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to assess the efficacy of different protocols. RESULTS: We initially identified 1113 different studies and included 33 of them which met the selection criteria. A meta-analysis of 11 retrospective studies that examined magnesium supplementation during hydration showed that this treatment provided significant protection against CIN (OR = 0.22, 95% CI = 0.14 to 0.35). CONCLUSION: There has been uncertainty regarding the best method to prevent CIN. Our results highlight the potentially protective effect of magnesium supplementation during hydration. This study is registered in PROSPERO, CRD42020212682.
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Cisplatino , Insuficiencia Renal , Humanos , Cisplatino/efectos adversos , Hidróxido de Magnesio , Magnesio/uso terapéutico , Estudios Retrospectivos , Insuficiencia Renal/inducido químicamente , Suplementos Dietéticos , Revisiones Sistemáticas como Asunto , Metaanálisis como AsuntoRESUMEN
In this study, the magnesium oxide (MgO)-based adsorbents [granulated MgO aggregates (GA-MgO) and surface-modified MgO powder (SM-MgO)] were developed to remediate a fluoride-contaminated groundwater site. Both GA-MgO and SM-MgO had porous, spherical, and crystalline structures. Diameters for GA-MgO and SM-MgO were 1-1.7 mm and 1-10 µm, respectively. The pseudo second-order dynamic adsorption and the Freundlich isotherm could be applied to express the chemical adsorption phenomena. The monolayer adsorption was the dominant mechanism at the initial adsorption period. During the latter part of fluoride adsorption, the multilayer adsorption became the dominant mechanism for fluoride removal from the water phase, which also resulted in the increased adsorption capacity. Higher hydroxide, phosphate, and carbonate concentrations caused a decreased fluoride removal efficiency due to the competition of sorption sites between fluoride and other anions with similar electronic properties. Fluoride removal mechanism using GA-MgO and SM-MgO as the adsorbents was mainly carried out by the chemical adsorption. Reaction paths contained two main processes: (1) formation of magnesium hydroxide after the reaction of MgO with water, and (2) the hydroxyl group of the magnesium hydroxide was replaced by fluoride ions to form magnesium fluoride precipitation. Results from column tests show that up to 61 and 73% of fluoride removal (initial fluoride concentration = 9.3 mg/L) could be obtained after 50 pore volumes of groundwater pumping with GA-MgO and SM-MgO injection, respectively. The GA-MgO system could be applied to contain and remediate fluoride-contaminated groundwater, and SM-MgO could be applied as an immediate fluoride removal alternative to achieve a rapid pollutant removal for emergency responses. Up to 71% of fluoride removal (fluoride concentration = 10.8 mg/L) could be obtained with GA-MgO injection after 30 days of operation. The developed GA-MgO system is a potential and green remediation alternative to contain the fluoride plume significantly.
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Agua Subterránea , Contaminantes Químicos del Agua , Óxido de Magnesio/química , Fluoruros , Hidróxido de Magnesio , Contaminantes Químicos del Agua/análisis , Adsorción , Agua , Cinética , Concentración de Iones de HidrógenoRESUMEN
Magnesium hydroxide [Mg(OH)2] is a non-hazardous chemical widely applied in sewer systems for managing odour and corrosion. Despite its proven effectiveness in mitigating these issues, the impacts of dosing Mg(OH)2 in sewers on downstream wastewater treatment plants have not been comprehensively investigated. Through a one-year operation of laboratory-scale urban wastewater systems, including sewer reactors, sequencing batch reactors, and anaerobic sludge digesters, the findings indicated that Mg(OH)2 dosing in sewer systems had multifaceted benefits on downstream treatment processes. Compared to the control, the Mg(OH)2-dosed experimental system displayed elevated sewage pH (8.8±0.1vs 7.1±0.1), reduced sulfide concentration by 35.1%±4.9% (6.7±0.9mgSL-1), and lower methane concentration by 58.0%±4.9% (19.1±3.6mgCODL-1). Additionally, it increased alkalinity by 16.3%±2.2% (51.9±5.4mgCaCO3L-1), and volatile fatty acids concentration by 207.4%±22.2% (56.6±9.0mgCODL-1) in sewer effluent. While these changes offered limited advantages for downstream nitrogen removal in systems with sufficient alkalinity and carbon sources, significant improvements in ammonium oxidation rate and NOx reduction rate were observed in cases with limited alkalinity and carbon sources availability. Moreover, Mg(OH)2 dosing in upstream did not have any detrimental effects on anaerobic sludge digesters. Magnesium-phosphate precipitation led to a 31.7%±4.1% reduction in phosphate concertation in anaerobic digester sludge supernatant (56.1±10.4mgPL-1). The retention of magnesium in sludge increased settleability by 13.9%±1.6% and improved digested sludge dewaterability by 10.7%±5.3%. Consequently, the use of Mg(OH)2 dosing in sewers could potentially reduce downstream chemical demand and costs for carbon sources (e.g., acetate), pH adjustment and sludge dewatering.
Asunto(s)
Aguas del Alcantarillado , Eliminación de Residuos Líquidos , Hidróxido de Magnesio , Magnesio , Hierro , Fosfatos , CarbonoRESUMEN
Alzheimer's disease (AD) is a neurodegenerative disease marked by mitochondrial dysfunction, amyloid-ß (Aß) aggregation, and neuronal cell loss. G-protein-coupled receptor 55 (GPR55) has been used as a promising target for insulin receptors in diabetes therapy, but GPR55's role in AD is still unidentified. Gelatin (GE) and polyethylene glycol (PEG) polymeric hydrogels are commonly used in the drug delivery system. Therefore, the aim of the present study was the preparation of magnesium hydroxide nanocomposite using Clitoria ternatea (CT) flower extract, GE, and PEG (GE/PEG/Mg(OH)2NCs) by the green precipitation method. The synthesized GE/PEG/Mg(OH)2NCs were used to determine the effect of GPR55 activation of intracerebroventricular administration on streptozotocin (ICV-STC)-induced cholinergic dysfunction, oxidative stress, neuroinflammation, and cognitive deficits. The GE/PEG/Mg(OH)2NCs were administered following bilateral ICV-STC administration (3 mg/kg) in experimental rats. Neurobehavioral assessments were performed using a Morris water maze (MWM) and a passive avoidance test (PA). Cholinergic and antioxidant activity, oxidative stress, and mitochondrial complex activity were estimated in the cortex and hippocampus through biochemical analysis. Inflammatory markers (TNF-α, IL-6, and IL-1ß) were determined using the ELISA method. Our study results demonstrated that the GE/PEG/Mg(OH)2NCs treatment significantly improved spatial and non-spatial memory functions in behavioral studies. Moreover, the treatment with GE/PEG/Mg(OH)2NCs group significantly attenuated cholinergic dysfunction, oxidative stress, and inflammatory markers, and also highly improved anti-oxidant activity (GSH, SOD, CAT, and GPx) in the cortex and hippocampus regions. The western blot results suggest the activation of the GPR55 protein expression through GE/PEG/Mg(OH)2NCs. The histopathological studies showed clear cytoplasm and healthy neurons, effectively promoting neuronal activity. Furthermore, the molecular docking results demonstrated the binding affinity and potential interactions of the compounds with the AChE enzyme. In conclusion, the GE/PEG/Mg(OH)2NCs treated groups showed reduced neurotoxicity and have the potential as a therapeutic agent to effectively target AD.
Asunto(s)
Enfermedad de Alzheimer , Inhibidores de la Colinesterasa , Nanopartículas , Enfermedades Neurodegenerativas , Animales , Ratas , Acetilcolinesterasa/metabolismo , Enfermedad de Alzheimer/tratamiento farmacológico , Enfermedad de Alzheimer/metabolismo , Antioxidantes/farmacología , Colinérgicos/metabolismo , Colinérgicos/farmacología , Colinérgicos/uso terapéutico , Modelos Animales de Enfermedad , Gelatina/metabolismo , Gelatina/farmacología , Gelatina/uso terapéutico , Hipocampo/metabolismo , Hidróxido de Magnesio/metabolismo , Hidróxido de Magnesio/farmacología , Hidróxido de Magnesio/uso terapéutico , Simulación del Acoplamiento Molecular , Enfermedades Neurodegenerativas/tratamiento farmacológico , Enfermedades Neurodegenerativas/metabolismo , Estrés Oxidativo , Polietilenglicoles/farmacología , Polietilenglicoles/metabolismo , Polietilenglicoles/uso terapéutico , Receptores de Cannabinoides/metabolismo , Receptores de Cannabinoides/uso terapéutico , Receptores Acoplados a Proteínas G/antagonistas & inhibidores , Receptores Acoplados a Proteínas G/metabolismo , Inhibidores de la Colinesterasa/química , Inhibidores de la Colinesterasa/farmacología , Nanopartículas/química , Nanopartículas/uso terapéuticoRESUMEN
Hydrophilic nanosized minerals exposed to air moisture host thin water films that are key drivers of reactions of interest in nature and technology. Water films can trigger irreversible mineralogical transformations, and control chemical fluxes across networks of aggregated nanomaterials. Using X-ray diffraction, vibrational spectroscopy, electron microscopy, and (micro)gravimetry, we tracked water film-driven transformations of periclase (MgO) nanocubes to brucite (Mg(OH)2) nanosheets. We show that three monolayer-thick water films first triggered the nucleation-limited growth of brucite, and that water film loadings continuously increased as newly-formed brucite nanosheets captured air moisture. Small (8 nm-wide) nanocubes were completely converted to brucite under this regime while growth on larger (32 nm-wide) nanocubes transitioned to a diffusion-limited regime when (â¼0.9 nm-thick) brucite nanocoatings began hampering the flux of reactive species. We also show that intra- and inter-particle microporosity hosted a hydration network that sustained GPa-level crystallization pressures, compressing interlayer brucite spacing during growth. This was prevalent in aggregated 8 nm wide nanocubes, which formed a maze-like network of slit-shaped pores. By resolving the impact of nanocube size and microporosity on reaction yields and crystallization pressures, this work provides new insight into the study of mineralogical transformations induced by nanometric water films. Our findings can be applied to structurally related minerals important to nature and technology, as well as to advance ideas on crystal growth under nanoconfinement.
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Óxido de Magnesio , Agua , Agua/química , Hidróxido de Magnesio/química , Hidroxilación , Minerales/químicaRESUMEN
In this paper, we synthesized graphene quantum dots magnesium hydroxide nanocomposites (GQDs/Mg(OH)2). The synthesized nanocomposites were characterized by UV-Vis spectroscopy, X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Malvern Zetasizer. The antimicrobial and antioxidant properties of the obtained GQDs/Mg(OH)2 nanocomposites were investigated. GQDs/Mg(OH)2 nanocomposites have MIC values of 15.625 µg/mL against fungi (C. metapsilosis and C. parapsilosis) and 62.5 µg/mL against Gram (+) (S. pneumonia and E. faecalis) and Gram (-) (E. coli). The synthesized GQDs/Mg(OH)2 nanocomposites showed moderate antioxidant activity. The results showed that at 100-µg/mL GQDs/Mg(OH)2 nanocomposite concentration, the H2O2 scavenging activity was 62.18%.
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Antiinfecciosos , Grafito , Nanocompuestos , Puntos Cuánticos , Puntos Cuánticos/química , Antioxidantes/farmacología , Grafito/farmacología , Grafito/química , Hidróxido de Magnesio , Peróxido de Hidrógeno/farmacología , Escherichia coli , Antiinfecciosos/farmacología , Nanocompuestos/químicaRESUMEN
BACKGROUND: Opioid-induced constipation (OIC) is a common symptom in cancer patients treated with opioids with a prevalence of up to 59%. International guidelines recommend standard laxatives such as macrogol/electrolytes and magnesium hydroxide to prevent OIC, although evidence from randomized controlled trials is largely lacking. The aim of our study is to compare magnesium hydroxide with macrogol /electrolytes in the prevention of OIC in patients with incurable cancer and to compare side-effects, tolerability and cost-effectiveness. METHODS: Our study is an open-label, randomized, multicenter study to examine if magnesium hydroxide is non-inferior to macrogol/electrolytes in the prevention of OIC. In total, 330 patients with incurable cancer, starting with opioids for pain management, will be randomized to treatment with either macrogol/electrolytes or magnesium hydroxide. The primary outcome measure is the proportion of patients with a score of < 30 on the Bowel Function Index (BFI), measured on day 14. The Rome IV criteria for constipation, side effects of and satisfaction with laxatives, pain scores, quality of life (using the EQ-5D-5L), daily use of laxatives and escape medication, and cost-effectiveness will also be assessed. DISCUSSION: In this study we aim to examine if magnesium hydroxide is non-inferior to macrogol/electrolytes in the prevention of OIC. The outcome of our study will contribute to prevention of OIC and scientific evidence of guidelines on (opioid-induced) constipation. TRIAL REGISTRATION: This trial is registered at clinicaltrials.gov: NCT05216328 and in the Dutch trial register: NTR80508. EudraCT number 2022-000408-36.