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Polymers May 2024Magnesium hydroxide, as a green inorganic flame-retardancy additive, has been widely used in polymer flame retardancy. However, magnesium hydroxide is difficult to...
Magnesium hydroxide, as a green inorganic flame-retardancy additive, has been widely used in polymer flame retardancy. However, magnesium hydroxide is difficult to disperse with epoxy resin (EP), and its flame-retardancy performance is poor, so it is difficult to use in flame-retardant epoxy resin. In this study, an efficient magnesium hydroxide-based flame retardant (MH@PPAC) was prepared by surface modification of 2-(diphenyl phosphine) benzoic acid (PPAC) using a simple method. The effect of MH@PPAC on the flame-retardancy properties for epoxy resins was investigated, and the flame-retardancy mechanism was studied. The results show that 5 wt% MH@PPAC can increase the limiting oxygen index for EP from 24.1% to 38.9%, achieving a V-0 rating. At the same time, compared to EP, the peak heat release rate, peak smoke production rate, total smoke production rate, and peak CO generation rate for EP/5 wt% MH@PPAC composite material decreased by 53%, 45%, 51.85%, and 53.13% respectively. The cooperative effect for PPAC and MH promotes the formation of a continuous and dense char layer during the combustion process for the EP-blend material, significantly reducing the exchange for heat and combustible gases, and effectively hindering the combustion process. Additionally, the surface modification of PPAC enhances the dispersion of MH in the EP matrix, endowing EP with superior mechanical properties that meet practical application requirements, thereby expanding the application scope for flame-retardant EP-blend materials.
PubMed: 38891418
DOI: 10.3390/polym16111471 -
Chemosphere Aug 2024Easy synthesis of efficient, non-toxic photocatalysts is a target to expand their potential applications. In this research, the role of Eu doping in the non-toxic,...
Easy synthesis of efficient, non-toxic photocatalysts is a target to expand their potential applications. In this research, the role of Eu 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 (Eu/M percentage) ranging from 2 to 15. Due to the higher ionic radius and lower polarizability of Eu 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 Eu 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 NO removal efficiency, ∼ 51% (UV-Vis) and 39% (visible light irradiation, 420 nm), with excellent selectivity (> 96 %), stability (> 7 h), and enhanced release of •O radicals. Such results demonstrate a simple way to design photocatalytic HTlcs suitable for air purification technologies.
Topics: Europium; Catalysis; Magnesium Hydroxide; Aluminum Hydroxide; Oxidation-Reduction; Nitrogen Oxides; Photochemical Processes; Light; Air Pollutants
PubMed: 38851500
DOI: 10.1016/j.chemosphere.2024.142555 -
Caspian Journal of Internal Medicine 2024Flaxseed powder seems to improve bowel movements in these patients. Therefore, this study compares the effects of flaxseed powder and magnesium hydroxide on bowel...
BACKGROUND
Flaxseed powder seems to improve bowel movements in these patients. Therefore, this study compares the effects of flaxseed powder and magnesium hydroxide on bowel movements of acute myocardial infarction patients hospitalized in ICU.
METHODS
The population of the present parallel randomized controlled clinical trial included 70 acute myocardial infarction patients hospitalized in ICU who had no history of chronic constipation. The patients in the intervention group were given three sachets of flaxseed powder (each sachet was 3 g) twice a day for four days. The patients in the control group were given 20 cc of magnesium hydroxide syrup each morning. The Bristol scale was used to describe stool consistency.
RESULTS
The mean and standard deviation of the number of bowel movements within five days after intervention are 1.86 ± 1.08 and 1.6 ± 0.65 in the intervention and the control groups, respectively. The frequency of normal stool consistency of the first bowel movement is 94.3% for the intervention group and 85.7% for the control group, which shows no significant differences between the two groups in terms of stool consistency and bowel movement frequency (P=0.510). The bowel movements started on average after 35.2±97.97 hours in the flaxseed group and 24.771±2.677 hours in the magnesium hydroxide group (P=0.023).
CONCLUSION
The results showed that flaxseed powder increases bowel movement frequency and improves the patients' stool consistency, but the differences between the two groups are insignificant. Finally, the time to the first defecation was shorter in the magnesium hydroxide group.
PubMed: 38807721
DOI: 10.22088/cjim.15.2.234 -
Materials (Basel, Switzerland) May 2024Red mud (RM) is an industrial waste generated in the process of aluminum refinement. The recycling and reusing of RM have become urgent problems to be solved. To explore...
Red mud (RM) is an industrial waste generated in the process of aluminum refinement. The recycling and reusing of RM have become urgent problems to be solved. To explore the feasibility of using RM in geotechnical engineering, this study combined magnesium oxide (MgO) (or calcium oxide (CaO)) with RM as an RM-based binder, which was then used to stabilize the soil. The physical, mechanical, and micro-structural properties of the stabilized soil were investigated. As the content of MgO or CaO in the mixture increased, the unconfined compressive strength (UCS) of the RM-based cementitious materials first increased and then decreased. For the soils stabilized with RM-MgO or RM-CaO, the UCS increased and then decreased, reaching a maximum at RM:MgO = 5:5 or RM:CaO = 8:2. The addition of sodium hydroxide (NaOH) promoted the hydration reaction. The UCS enhancement ranged from 8.09% to 66.67% for the RM-MgO stabilized soils and 204.6% to 346.6% for the RM-CaO stabilized soils. The optimum ratio of the RM-MgO stabilized soil (with NaOH) was 2:8, while that of the RM-CaO stabilized soil (with NaOH) was 4:6. Freeze-thaw cycles reduced the UCS of the stabilized soil, but the resistance of the stabilized soil to freeze-thaw erosion was significantly improved by the addition of RM-MgO or RM-CaO, and the soil stabilized with RM-MgO had better freeze-thaw resistance than that with RM-CaO. The hydrated magnesium silicate generated by the RM-MgO stabilized soil and the hydrated calcium silicate generated by the RM-CaO stabilized soil helped to improve the UCS of the stabilized soil. The freeze-thaw cycles did not weaken the formation of hydration products in the stabilized soil but could result in physical damage to the stabilized soils. The decrease in the UCS of the stabilized soil was mainly due to physical damage.
PubMed: 38793407
DOI: 10.3390/ma17102340 -
International Journal of Nanomedicine 2024The committed differentiation fate regulation has been a difficult problem in the fields of stem cell research, evidence showed that nanomaterials could promote the...
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 mA 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 mA RNA methylation process, and the major modification enzyme in LDH controlled NPCs differentiation may be the mA RNA methyltransferase METTL3. The upregulated METTL3 by LDH increased the mA level of mRNA, enhancing its stability.
CONCLUSION
This work reveals that MgAl-LDH nanoparticles can regulate the differentiation of ESCs into NPCs by increasing mA RNA methylation modification of .
Topics: Cell Differentiation; Animals; Neural Stem Cells; Mice; Nanoparticles; Methylation; Hydroxides; Methyltransferases; Particle Size; Embryonic Stem Cells; Adenosine; Aluminum Hydroxide; Magnesium Hydroxide
PubMed: 38766656
DOI: 10.2147/IJN.S463141 -
Enhancing iron content and growth of cucumber seedlings with MgFe-LDHs under low-temperature stress.Journal of Nanobiotechnology May 2024The development of cost-effective and eco-friendly fertilizers is crucial for enhancing iron (Fe) uptake in crops and can help alleviate dietary Fe deficiencies,...
The development of cost-effective and eco-friendly fertilizers is crucial for enhancing iron (Fe) uptake in crops and can help alleviate dietary Fe deficiencies, especially in populations with limited access to meat. This study focused on the application of MgFe-layered double hydroxide nanoparticles (MgFe-LDHs) as a potential solution. We successfully synthesized and characterized MgFe-LDHs and observed that 1-10 mg/L MgFe-LDHs improved cucumber seed germination and water uptake. Notably, the application of 10 mg/L MgFe-LDHs to roots significantly increased the seedling emergence rate and growth under low-temperature stress. The application of 10 mg/L MgFe-LDHs during sowing increased the root length, lateral root number, root fresh weight, aboveground fresh weight, and hypocotyl length under low-temperature stress. A comprehensive analysis integrating plant physiology, nutrition, and transcriptomics suggested that MgFe-LDHs improve cold tolerance by upregulating SA to stimulate CsFAD3 expression, elevating GA levels for enhanced nitrogen metabolism and protein synthesis, and reducing levels of ABA and JA to support seedling emergence rate and growth, along with increasing the expression and activity of peroxidase genes. SEM and FTIR further confirmed the adsorption of MgFe-LDHs onto the root hairs in the mature zone of the root apex. Remarkably, MgFe-LDHs application led to a 46% increase (p < 0.05) in the Fe content within cucumber seedlings, a phenomenon not observed with comparable iron salt solutions, suggesting that the nanocrystalline nature of MgFe-LDHs enhances their absorption efficiency in plants. Additionally, MgFe-LDHs significantly increased the nitrogen (N) content of the seedlings by 12% (p < 0.05), promoting nitrogen fixation in the cucumber seedlings. These results pave the way for the development and use of LDH-based Fe fertilizers.
Topics: Cucumis sativus; Seedlings; Iron; Cold Temperature; Plant Roots; Germination; Hydroxides; Fertilizers; Gene Expression Regulation, Plant; Nanoparticles; Stress, Physiological; Magnesium
PubMed: 38764056
DOI: 10.1186/s12951-024-02545-x -
Environmental Science and Pollution... May 2024Contaminations by pharmaceuticals, personal care products, and other emerging pollutants in water resources have become a seriously burgeoning issue of global concern in...
Contaminations by pharmaceuticals, personal care products, and other emerging pollutants in water resources have become a seriously burgeoning issue of global concern in the first third of the twenty-first century. As societal reliance on pharmaceuticals continues to escalate, the inadvertent introduction of these substances into water reservoirs poses a consequential environmental threat. Therefore, the aim of this study was to investigate reductive degradation, particularly, catalytic hydrogenation regarding model pollutants such as diclofenac (DCF), ibuprofen (IBP), 17α-ethinylestradiol (EE2), or bisphenol-A (BPA), respectively, in aqueous solutions at lab scale. Iron bimetals (zero valent iron, ZVI, and copper, Cu, or nickel, Ni) as well as zero valent magnesium (Mg, ZVM) in combination with rhodium, Rh, or palladium, Pd, as hydrogenation catalysts (HK), were investigated. Studies were executed through various short-term batch experiments, with multiple sample collections, over a total range of 120 min. The results indicated that DCF was attenuated at over 90 % when exposed to Fe-Cu or a Fe-Ni bimetal (applied as a single model pollutant). However, when DCF was part of a mixture alongside with IBP, EE2, and BPA, the attenuation efficacy decreased to 79 % with Fe-Cu and 23 % with Fe-Ni. Conversely, both IBP and BPA exhibit notably low attenuation levels with both bimetals, less than 50 %, both deployed as single substances or in mixtures. No reaction (degradation) products could be identified employing LC-MS, but sometimes a release of the parent pollutant when applying an acetic acid buffer could be noted to a certain extent, suggesting adsorption processes on corrosion products such as iron hydroxide and/or oxides. Surprisingly, Mg in combination with Rh (Rh-HK) or Pd (Pd-HK) showed a significantly rapid decrease in the concentrations of DCF, EE2, and BPA, in part up to approximately 100 %, that is, within a few minutes only in part due to hydrogenation degradation reactions (related reaction products could actually be identified by LC-MS; adsorption processes were not observed here). Moreover, kinetic modeling of the DCF degradation with Mg-Rh-HK was conducted at different temperatures (15 °C, 20 °C, 25 °C, 35 °C) and varied initial concentrations (2.5 mg/L, 5.0 mg/L, 7.5 mg/L, 10.0 mg/L). The outcomes prove that the degradation of DCF at the Rh-HK's surface followed a modified first-order kinetics, most probably by catalytic hydrodehalogenation and subsequent hydrogenation of the aromatic moieties (molecular hydrogen was provided by the corrosion of Mg). From the determined reaction rate constants at four different temperatures, the activation energy was estimated to be 59.6 kJ/mol by means of the Arrhenius equation what is in good agreement with similar results reported in the literature. This coupled hydrodehalogenation and hydrogenation approach may be upscaled into a new promising technical process for comprehensively removing such pharmaceuticals and similar pollutants in sewage plants in a single step, furthermore, even in combination with adsorption by activated carbon and/or ozonation which have already been established at some sewage plants in Switzerland and Germany recently.
Topics: Water Pollutants, Chemical; Catalysis; Pharmaceutical Preparations; Magnesium; Hydrogen; Benzhydryl Compounds; Metals; Phenols
PubMed: 38744765
DOI: 10.1007/s11356-024-32777-1 -
Materials (Basel, Switzerland) Apr 2024Utilizing MgO as the precursor and deionized water as the solvent, this study synthesized nanoparticles of Mg(OH) via hydrothermal methods, aiming to control its purity,...
Utilizing MgO as the precursor and deionized water as the solvent, this study synthesized nanoparticles of Mg(OH) via hydrothermal methods, aiming to control its purity, particle size, and morphology by understanding its growth under non-uniform nucleation. Characterization of crystal morphology and structure was conducted through scanning electron microscopy and X-ray diffraction, while laser particle size detection assessed the secondary particle size distribution. The study focused on how MgO's hydrothermal process conditions influence Mg(OH) crystal growth, particularly through ion concentration and release rate adjustments to direct crystal growth facets. These adjustments shifted the dominant growth plane, enhancing the peak intensity ratio I001/I101 from 1.03 to 2.14, thereby reducing surface polarity and secondary aggregation of crystals. The study of the physicochemical properties of the same sample at different times revealed the pattern of crystal dissolution and recrystallization. A 2 h hydrothermal reaction notably altered the particle size distribution, with a decrease in particles sized 0.2~0.4 μm and an increase in those sized 0.4~0.6 μm, alongside new particles over 1 μm, indicating a shift toward uniformity through dissolution and recrystallization. Optimal conditions (6% magnesium oxide concentration, 160 °C, 2 h) led to the synthesis of highly dispersed, uniformly sized magnesium hydroxide, showcasing a simple, eco-friendly, and high-yield process.
PubMed: 38730761
DOI: 10.3390/ma17091956 -
ACS Omega Apr 2024Layered double hydroxide (LDH) films have received extensive attention for their unique physical barrier function and ion exchange properties, which make them promising...
Layered double hydroxide (LDH) films have received extensive attention for their unique physical barrier function and ion exchange properties, which make them promising candidates for corrosion protection of magnesium alloys. In this paper, we used the multiple polynomial regression fitting method to establish a regression equation for the electrochemical corrosion resistance with the reaction temperature (), pH, and reaction time () of the Mg-Al LDH film on the AZ91D magnesium alloy. The goodness of fit, confidence, and residual analyses confirmed the high accuracy of the model equation. According to the calculation using the fmincon function, the best corrosion resistance of the prepared samples could be achieved when the parameters are = 135 °C, pH = 12.0, and = 15 h. Then, the experimental results showed that the corrosion current density () of the obtained LDH film under the above conditions could be 1.07 × 10 A/cm, approximately 3 orders of magnitude lower than the magnesium alloy substrate, after immersion in a 3.5 wt % NaCl solution for 180 h, the surface structure of the LDH film did not change significantly, and the was still 2 orders of magnitude higher than that of the magnesium alloy substrate. Hence, a synergistic effect equation for the reaction temperature, pH, and reaction time on the corrosion resistance of the LDH film on a magnesium alloy surface prepared by the hydrothermal method was obtained. Moreover, using this equation, we obtained an LDH film with good corrosion resistance and durability, providing theoretical guidance for optimizing the process of preparing the LDH film by the hydrothermal method in practical applications.
PubMed: 38708272
DOI: 10.1021/acsomega.3c10297 -
RSC Advances May 2024Magnesium hydroxide (Mg(OH)), as a green halogen-free flame retardant, has attracted significant attention in the field of flame retardant composite materials. In...
Magnesium hydroxide (Mg(OH)), as a green halogen-free flame retardant, has attracted significant attention in the field of flame retardant composite materials. In addition to conventional indicators such as purity and whiteness, Mg(OH) is required to take the form of regular hexagonal sheets to ensure the dispersion of composite materials. We use irregular large particles of Mg(OH) prepared by the magnesium factory in western Qinghai as raw materials to study the influence of alkali metal ions K and Na mainly present in salt lakes on the physicochemical properties of Mg(OH). The products were characterized X-ray diffraction, scanning electron microscopy, automatic nitrogen physical adsorption apparatus, and other modern characterization techniques. Results show that alkali metal ions K and Na considerably influence the crystal surface polarity, particle size, and morphology of the prepared Mg(OH). The mechanism analysis shows that the presence of K and Na alters the dissolution, recrystallization, and growth characteristics of Mg(OH). This study provides theoretical support for the realization of high-performance Mg(OH) using salt lake resources and demonstrates the value for promoting the large-scale industrial application of the salt lake industry.
PubMed: 38708105
DOI: 10.1039/d4ra00305e