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In this study, a phosphorus-containing and polyether structure modifier, phenolic epoxy phosphate ester (PEPE), was prepared by the reaction of phenolic epoxy resin (EPN) and phosphoric acid. It was used to solve the trade-off dilemma of simultaneously improving the mechanical properties and flame resistance of flexible poly (vinyl chloride) (fPVC)/magnesium hydroxide (MH) composites. The peak heat release rate, total heat release, peak smoke production rate, and total smoke production of the fPVC/MHPEPE-5 (PEPE modified MH as filler) composite were decreased by 35.31 %, 49.2 %, 40.42 %, and 27.26 %, respectively, in comparison with the fPVC/MH composite. More importantly, the fPVC/MHPEPE-5 composite passed V-0 rating in the UL-94 test, while the fPVC and fPVC/MH composite passed V-2 and V-1 rating. The presence of phosphorus compounds in the condensed phase promoted the formation of a dense char residue of the fPVC/MHPEPE-5 composite. Therefore, the heat and flammable volatiles cannot migrate between the substrate zone and the combustion zone. In the gas phase, the dilution effect of H2O reduced the concentration of oxygen and combustible volatiles. The radicals quenching effect of the primary and secondary pyrolysis products of PEPE (such as PO· and PO2·) with ·H and ·OH. radicals played a crucial role in flame extinguishing and combustion termination. In addition, the scanning electron microscopy results showed that MHPEPE performed good compatibility with the fPVC matrix. The tensile and impact strength of the fPVC/MHPEPE-5 composite was 12.19 % and 19.26 % higher than that of the fPVC/MH composite, respectively.

Thermochemical energy storage (TCES) presents a promising method for energy storage due to its high storage density and capacity for long-term storage. A combination of TCES and district heating networks exhibits an appealing alternative to natural gas boilers, particularly through the utilisation of industrial waste heat to achieve the UK government's target of Net Zero by 2050. The most pivotal aspects of TCES design are the selected materials, reactor configuration, and heat transfer efficiency. Among the array of potential reactors, the fluidised bed emerges as a novel solution due to its ability to bypass traditional design limitations; the fluidised nature of these reactors provides high heat transfer coefficients, improved mixing and uniformity, and greater fluid-particle contact. This research endeavours to assess the enhancement of thermochemical fluidised bed systems through material characterisation and development techniques, alongside the optimisation of heat transfer. The analysis underscores the appeal of calcium and magnesium hydroxides for TCES, particularly when providing a buffer between medium-grade waste heat supply and district heat demand. Enhancement techniques such as doping and nanomaterial/composite coating are also explored, which are found to improve agglomeration, flowability, and operating conditions of the hydroxide systems. Furthermore, the optimisation of heat transfer prompted an evaluation of heat exchanger configurations and heat transfer fluids. Helical coil heat exchangers are predominantly favoured over alternative configurations, while various heat transfer fluids are considered advantageous depending on TCES material selection. In particular, water and synthetic liquids are compared according to their thermal efficiencies and performances at elevated operating temperatures. [ABSTRACT FROM AUTHOR]

AbstractThe sorption of uranium on standard Nano magnesium hydroxide was studied. Nanoparticles Mg(OH)2 was prepared from bittern via the precipitation process. The pilot nano magnesium hydroxide was calcined at 300 °C for 3 hours to remove some byproducts such as chlorartinite and hydromagnesite. The structure, morphology, and chemical composition of standard nano Mg(OH)2 Mg(OH)2-st, pilot Mg(OH)2, and calcined pilot Mg(OH)2 were characterized using XRD, SEM, EDX, Raman and TEM. Adsorption of standard Mg(OH)2 was described by the Langmuir model, whereas kinetics was investigated using pseudo-second-order models. Mg(OH)2 calcined at 300 °C showed the highest uranium uptake at 217 mg/g. This was reached at pH 4, contact time of 20 min, solid-to-liquid ratio of 10 g/L, and uranium initial concentration of 875 mg/L at 20 (±2)°C, this could be explained by the increase of pore volume and surface area. Desorption of Uranium ions from loaded Mg(OH)2-st particles was performed in a batch mode. Elution efficiency reached about 100% using 0.5 molL−1 H2SO4 and 15 minute contact time. [ABSTRACT FROM AUTHOR]

Introduction: Cardiac arrhythmias are a prevalent issue following surgeries, with hypomagnesemia often associated with this complication. Prophylactic administration of intravenous magnesium has been a standard practice for patients admitted in ICU. This study aimed to compare the efficacy of oral versus intravenous magnesium in preventing hypomagnesemia and arrhythmias. Methods: In this interventional clinical study, 98 patients were randomly allocated into two groups. Baseline serum magnesium levels and arrhythmias were assessed for all patients. One group received 1.6 gm of oral magnesium hydroxide via nasogastric (NG) tube, while the other group was administered 2 g of magnesium sulfate at the induction of anesthesia. Serum magnesium levels were monitored for 48 hours postoperatively. Results: The preoperative hypomagnesemia difference between the groups was not statistically significant. During surgery, serum magnesium levels peaked at approximately 4 mg/dL, with no hypomagnesemia observed in any patient. Although the serum magnesium levels in the oral group decreased in parallel but remained below those in the intravenous (IV) group, no significant differences were observed during postoperative monitoring. Additionally, the prevalence of arrhythmias was 14.60% in the IV group and 6.83% in the oral group (OR=0.44). Conclusion: Administering 1.6 gm of oral magnesium hydroxide is as effective as 2 gm of intravenous magnesium sulfate in preventing hypomagnesemia and arrhythmias. This study suggests that oral magnesium supplementation is a promising, cost-effective alternative. [ABSTRACT FROM AUTHOR]

Although Indonesia has set a target for increasing the use of renewable energy for electricity generation, the use of coal as a source of energy will still dominate at least until 2040. Sulfur dioxide (SO2) along with other gases and particulates released from the use of coal in coal-fired power plants (CFPPs) may cause air pollution. The use of seawater, an abundant source of absorbent in a maritime country such as Indonesia, in flue gas desulfurization (SWFGD) absorbers, is an economical option for treating SO2 in an absorption tower compared to other alkaline chemicals, e.g. limestone (CaCO3) or magnesium hydroxide (Mg(OH)2). A model, which correlates the equilibrium of the reaction with the salinity of the absorbent, was developed to predict the sulfur dioxide scrubbing process inside an SWFGD absorber. The simulation also took into account the mass and energy balance during the scrubbing process. The calibration using field SWFGD data showed a good correspondence between field data and modelling results. [ABSTRACT FROM AUTHOR]

To promote the reuse of yellow gypsum (YG), an industrial solid waste, and achieve energy savings and environmental protection, the impact of water temperature variation on the performance of magnesium oxysulfate-based yellow gypsum (YG-MOS) foamed concrete was investigated. YG-MOS foamed concrete was prepared using magnesium oxysulfate (MOS) foamed cement as the matrix and YG as the admixture, with water at varying temperatures. This study aimed to elucidate how changes in water temperature affect the properties of YG-MOS foamed concrete. Results show that, after a 28-day curing period, as the water temperature increases, the compressive strength, dry density, and thermal conductivity of the samples initially rise but subsequently decline. These properties reach their peak values when the water temperature is 35 °C. Additionally, as the water temperature rises, the porosity of the samples first decreases and then increases, with the minimum porosity observed at 35 °C. At this temperature, the mean pore size and its standard deviation are also minimized, resulting in the most uniform pore size distribution. Furthermore, as the temperature varies between 35 °C and 60 °C, the concentration of the 5-phase 5Mg(OH)2·MgSO4·7H2O in the sample gradually decreases, while the formation of flake, cluster, and petal-like magnesium hydroxide structures significantly increases. These findings provide valuable insights for the application of YG-MOS foamed concrete in civil engineering. [ABSTRACT FROM AUTHOR]

Mineral-based flame retardants are widely used worldwide as they are both effective and inexpensive solutions. Especially alumina trihydrate (ATH) and magnesium hydroxide (MDH) are the first mineral additives that come to mind industrially due to their environmental friendliness and easy availability. In this study, the effectiveness of huntite-hydromagnesite mineral, which is not as widely used as the other two minerals, and its differences from its counterparts were investigated. For this purpose, composites with polyethylene carrier were produced by extruder method using binders at various ratios, and various physical, mechanical, and combustion properties of these samples were investigated. According to the data obtained, the samples containing huntite-hydromagnesite showed UL94 V0 class flame retardant performance with 5% less filler than their counterparts. The same samples showed superior mechanical properties in tensile strength between 23.4% and 70.8% and elongation at break between 60.7% and 73.1%. [ABSTRACT FROM AUTHOR]

In this article, the optimal conditions for synthesizing a new flame retardant based on pentaerythritol, phosphoric acid, and magnesium hydroxide are studied. In this case, the molar ratio of the initial substances was 3.64:1, and the synthesis duration was four hours. After the completion of this process, different (1, 3, and 5%) solutions of magnesium hydroxide were added at a temperature of 90 ºC for 3 hours. The yield of this reaction was 85%. Applying this obtained flame retardant to textile materials increases the fire resistance of textile materials. The composition of synthesized antiperine and antiperine applied textile fabrics was studied by IR spectrum, and the thermal decomposition of antiperine applied fabric was investigated by TGA and DTA analysis, and 100 μm sections of flame retardant treated fabrics were measured by scanning electron microscope. The fire resistance and physical mechanical properties of these materials were studied based on the requirements of GOST 50810-95. The oxygen index of the fabric treated with synthesized flame retardant was 35.6%. [ABSTRACT FROM AUTHOR]

Ink-paper historical documents, which are an important part of cultural heritage, can be damaged by various materials on the outside and the inside of the paper. Cotton fiber sheets treated with iron gall ink and then treated with stabilization materials were studied. Nanosized Mg(OH)2 was used as a deacidification material and potassium bromide, tetrabutylammonium bromide, or propyl gallate as antioxidant materials were investigated as a stabilization system for iron gall ink-damaged paper. All samples were artificially aged in the air for 150 h at 65 °C in a UV/moisture chamber or 500 h at 90 °C. The pH and alkaline reserve (AR) measurements, monitoring of color change, and scanning electron microscopy analysis data confirm that the aging effect is more destructive to the iron gall inked paper. The experiment results show that using alkaline materials with antioxidants, such as nano-Mg(OH)2 and propyl gallate, positively affects color changes of ink-damaged paper. Treatment with a stabilization system such as nanosized Mg(OH)2, a binder hydroxypropyl cellulose (Klucel), and an antioxidant as propyl gallate is a suitable method for iron gall ink damaged paper stabilization and preservation, according to the study results. [ABSTRACT FROM AUTHOR]

• Single and dual nanoparticle-based treatments are used for preserving materials. • Hardness and erosion properties were improved using these nanoparticles (NPs). • A new C-S-H cementing gel is formed when Ca(OH)2/SiO2 NPs are combined. • The NPs did not significantly alter water vapour permeability. • ΔE was suitable in all cases (0.40–3.79), except for Ca-NPS (5.10). This paper studies the effectiveness of four consolidation treatments based on nanoparticles suspensions: calcium hydroxide (Ca-NP), magnesium hydroxide (Mg-NP), a treatment combining calcium hydroxide and magnesium hydroxide (Ca/Mg-NP), and a treatment consisting of calcium hydroxide and silicon dioxide (Ca/Si-NP) that were both applied separately. The suspensions were sprayed on gypsum plasters and lime renders which are common substrates in historical constructions and show a high degree of similarity with the treatments. The consolidation efficiency was evaluated using non-destructive techniques, such as peeling test, Shore-D hardness, water flow using Karsten tube and water vapour permeability tests. In addition, TEM images and XRD tests demonstrated the formation of a new C-S-H cementing phase when Ca/Si-NPs were combined due to a reaction between Ca(OH) 2 with SiO 2. Colour tests (CIE-L*a*b*) showed the consolidants did not produce major colour alterations, although the Ca-NP treatment caused a slight lightness increase. The strengthening effect was greater in lime mortars and water flow was moderately reduced in all treatments, except in mortars coated with Ca/Mg-NP. Finally, the chemical nature of the treatments is similar to the substrates, and they did not significantly alter the water vapour permeability of the studied materials. [ABSTRACT FROM AUTHOR]

The hydration of magnesium-bearing minerals following calcination is a critical step in the manufacturing of magnesium hydroxide. However, the sensible heat of calcined minerals is not adequately exploited in the traditional procedure. It is worth investigating the hydration of hot calcined minerals directly, i.e., by quenching hydration, especially in hydration agent solutions. In this paper, calcined hydromagnesite was subjected to a series of quenching hydration experiments in a glycine solution. Several kinetic models were employed to describe the hydration process. The samples were characterized by XRD, SEM, and a laser diffraction analyzer. A pH-stat method was employed to determine the dissolution property of the hydrated products. The study found that quenching treatment had a pronounced positive effect on the hydration degree at 25°C, but that this effect diminished with increasing temperature. Chemical reactions govern the hydration of calcined hydromagnesite, with the quenching item having a lower activation energy than the control. The characterization results highlight the effect of quenching treatment at low temperature on the formation of hydrated Mg(OH)2 with poor crystallinity and irregular morphology, which in turn promotes the dissolution property. At pH 6.5, 97% of the quenching hydration product obtained at 25°C dissolved within 150 min. [ABSTRACT FROM AUTHOR]

Red mud is a highly alkaline solid waste discharged from the alumina industry, and its high sodium content is the key factor limiting its wide utilization. Therefore, effective control of the "frosting" phenomenon during the application of red mud has received significant attention. In this study, the changes of particle size, phase, morphology, and pore size of red mud after sodium removal with different amounts of citric acid pretreatment were investigated. The single-factor experiment shows that the Na+ leaching rate is 86.33% under a citric acid dosage of 15%, liquid-to-solid ratio of 7 mL/g, leaching temperature of 80 °C, stirring speed of 300 rpm, and leaching time of 10 min. The leachate is characterized through X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer–Emmett–Teller (BET) surface area analysis. The results reveal that Na+ mainly exists in a combined state in the form of cancrinite. With the increase of citric acid dosage, red mud agglomerates, calcite, and cancrinite are dissolved, and new phases such as calcium oxalate and magnesium aluminum hydroxide are formed. The specific surface area, pore volume, and pore diameter show irregular changes with the increase in the citric acid dosage. Citric acid pretreatment can effectively reduce the sodium content in red mud, the treatment cost of leaching solution is low, and the leaching residue is neutral, which is helpful to promote the practical application of red mud. [ABSTRACT FROM AUTHOR]

Inflammable building finishing materials act as a major cause of fire propagation, and they, therefore, pose significant risks to life and can lead to property damage. To replace such flammable building finishing materials, many countries have established regulations limiting their use, which has led to extensive research on the development of flame-retardant building finishing materials. Such methods have included adding flame retardants to construction materials to reduce the heat release rate and total heat release. The present study aimed to enhance the fire performance of cellulose-based architectural finishing materials by creating a dual flame-retardant mixture using expandable graphite and magnesium hydroxide added to recycled paper waste. Specimen fabrication involves using a pressing method to apply uniform pressure to compress the mixture in a mold. The total heat release (THR), CO, and CO2 production of the produced specimens were measured using a cone calorimeter while varying the magnesium hydroxide additive ratio. The combustion gases were measured through NES 713 experiments to determine any changes in the Toxic Index corresponding to variations in the magnesium hydroxide content. The experiment results established a correlation between the magnesium hydroxide additive ratio and the total heat release, as well as the existence of variations in CO and CO2 production for the dual flame-retardant recycled paper material. A database for combustion gases was also obtained. It was confirmed that the fire performance was improved by confirming that the total heat release decreased by 52% from the previous one in the magnesium hydroxide content of 30 g, and it was confirmed that the inflection points of the Toxic Index value due to the change in CO and CO2 gas production occurred in the magnesium hydroxide content of 20 g due to the improvement of the fire performance. Through the ISO 5660-1 experiment data, we have secured data that can be used as foundational information for performance-oriented fire risk assessments, thereby ensuring the fire safety of cellulose materials that are vulnerable to fire. [ABSTRACT FROM AUTHOR]

For obtaining flame retardant, oil resistance, high strength, and softness EVA/POE‐g‐MAH composites for cables, multifunctional modified magnesium hydroxide (MH‐KH570), and aluminum hydroxide (ATH‐KH570) were prepared by grafting γ‐(methacryloyloxy) propyltrimethoxysilane (KH570) onto the surface of MH and ATH. The successful grafting was confirmed by Fourier‐transform infrared spectrometer, scanning electron microscope, thermogravimetric analysis, and contact angle test. The hydrophobicity of MH and ATH was enhanced and the decompose time was extended, called the "sustained release" effect. The ethylene‐vinyl acetate copolymer (EVA)/maleic anhydride grafted polyolefin elastomer (POE‐g‐MAH) composites containing 62.5 wt% the mixture of MH‐KH570 and ATH‐KH570 in a 1:1 mass ratio was prepared. The vertical combustion test, limited oxygen index (LOI), and cone calorimetry proved the flame retardancy performance of the EVA/POE‐g‐MAH composites were enhanced, because of the homogeneous dispersion and the "sustained release" effect of MH‐KH570 and ATH‐KH570. The vertical combustion and LOI reached V‐0 and 38.1%. Importantly, the "crosslinking" effect of MH‐KH570 and ATH‐KH570 further enhanced the tensile strength after the composites crosslinked, and reached 19.9 MPa. In a word, a simple method for preparing flame retardant EVA/POE‐g‐MAH composites with high tensile strength was provided. [ABSTRACT FROM AUTHOR]

Magnesium oxysulfate (MOS) cement, a building material, can be considered the result of the hydration reaction between magnesium sulfate, caustic-burned magnesia powder, and water. Despite its desirable properties, such as limited mechanical strength and water resistance, MOS cement can hinder its use in engineering applications. We employed several testing methods to assess the impact of sodium gluconate (SG) addition on the compressive strength, microstructure, moisture resistance, coagulation time, pH profile, micropore parameters, phase composition, and thermal decomposition of MOS cement's hydration products. The addition of sodium gluconate improves the stability of the hydration film surrounding active magnesium oxide in magnesium sulfate. This extension in the setting time of MOS cement is observed. Additionally, it inhibits the creation of magnesium hydroxide while facilitating the formation of numerous needlelike structures corresponding to the 5Mg(OH)2·MgSO4·7H2O (5·1·7 phase). Consequently, the mechanical strength and water resistance of MOS cement are substantially improved compared to the unmodified sample. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Magnesium hydroxide (Mg(OH)2) nanoflakes were synthesized by surfactant-assisted sonochemical route with using of natural brine (containing MgCl2), NaOH, and polyethylene glycol as magnesium procedure, precipitator, and surfactant, respectively. The effect of ultrasound irradiation power was investigated in 3 levels (100, 200, and 350 W) on optical, structural, and morphological properties and thermal behavior of as-prepared magnesium hydroxide (MH) nanostructures. XRD, DLS, FESEM, TEM, EDS, FTIR, BET, and UV–visible spectroscopy techniques characterized the synthesized samples. XRD profiles and FESEM and TEM images of all as-synthesized samples disclosed that the Mg(OH)2 nanoflakes indicate hexagonal brucite-type crystallinity with space group P-3m1 without any impurity phases. Also, the crystallite size of samples was increased from 21 to 27 nm by incrementing the ultrasound irradiation power from 100 to 350 W, respectively. Due to the polycrystalline nature of the particles, the size of nanoflakes measured with DLS were 80, 105 and 140 nm for 100, 200, and 350 W irradiation powers, respectively. Well-dispersed Mg(OH)2 nanoflakes with a uniform size distribution were obtained using 100 W irradiation power. Also, FESEM and TEM images confirmed that increasing the ultrasonic wave power led to the accumulation of flakes, which based on BET studies can be due to the reduction of the specific surface area of nanoflakes from 115 m2/g (for 100 W irradiation) to 35 m2/g (for 350 W irradiation). The optical band gap energy of the nanoflakes was found to be slightly decreased with increasing with the increase of ultrasound irradiation power content. [ABSTRACT FROM AUTHOR]

In this study, seawater bittern, a by-product of sea salt production containing a concentrated inorganic substance, was used to recover magnesium in the form of nanostructured magnesium hydroxide/oxide. Mg(OH)2/MgO nanostructures from seawater bittern were synthesized by a precipitation method with different addition of PVA surfactants. The aim of this study was to investigate the effects of PVA surfactant on the morpho-structural properties and thermal behavior of MgO nanostructures. Simple control of the morphology and particle size of MgO nanostructures obtained by the addition of PVA was performed during synthesis. XRD structural analysis showed that the synthesized MgO samples have good crystalline nature. The average crystallite size of the samples is 26 nm, 26 nm, 23 nm, 24 nm, 23 nm and 23 nm, respectively, which decreases with increasing PVA content. Based on the average particle size, the optimum addition of poly(vinyl alcohol) is at a mass ratio of 1:1.5, since the smallest particles are obtained and have a uniform distribution. The SEM and TEM observations show an improvement in the agglomeration behavior of MgO nanoparticles by increasing the PVA content. The constituents of the samples were confirmed by XRF and EDS analysis. [ABSTRACT FROM AUTHOR]

The development of a renewable green sound-absorbing material is a very meaningful topic in solving the environmental pollution caused by traditional waste sound-absorbing materials. In this study, a cellulose-based dual network labyrinthine structure composite aerogel was developed by combining PVA staple fibers with magnesium hydroxide nano-flame retardant particles. Porous cellulose aerogels with a labyrinthine structure were constructed by adding PVA staple fibers. Due to the complex bending branching of fibers in the aerogel, the aerogel exhibits significantly enhanced acoustic absorption in the low to medium frequency range. The doping of short fibers in the porous structure constitutes a double network structure, which increases the propagation path of sound waves, and the noise reduction coefficient of the material is significantly increased. Meanwhile, in situ synthesis of magnesium hydroxide nanoparticles with flame retardant properties inside the cellulose aerogel structure can also provide good flame retardant properties. The resulting polyvinyl alcohol fiber doped magnesium hydroxide cellulose aerogel (MH NPs@PVA/Cellulose aerogel) exhibited an excellent noise reduction coefficient of 0.46 in the low to medium frequency range. The maximum noise reduction coefficient reached 0.53 when the air layer was 15 mm, an outstanding compressive strength of 1.107 MPa and 70% strain. Moreover, cellulose aerogels not only exhibit high porosity and low density but also show good flame retardant performance which can self-extinguish within 40 s. The green recyclable and degradable MH NPs@PVA/Cellulose aerogel presents great potential in the construction and decoration field. [ABSTRACT FROM AUTHOR]

Copyright of Plastics Science & Technology / Suliao Ke-Ji is the property of Plastics Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A trade‐off dilemma exists for simultaneously improving the mechanical properties and flame resistance of flexible polyvinyl chloride (fPVC)/magnesium hydroxide (MH) composites. In this study, epoxy phosphate ester (EPE), a hydrophobic surface modifier of MH, was synthesized using a self‐emulsification method. After modification, EPE was bonded to the surface of MH (MHEPE) without altering its morphology. The results of limiting oxygen index and cone calorimetry tests indicated that fPVC/MHEPE exhibited better flame retardancy and smoke suppression effects than did fPVC/MH. The peak of the heat release rate, total heat release, peak of the smoke production rate, and total smoke production of the fPVC/MHEPE composite were 206.0 kJ m−2, 45.90 MJ m−2, 0.0729 m2 s−1, and 9.88 m2, which were 8.64%, 14.00%, 27.61%, and 9.02% lower than those of the fPVC/MH composite, respectively. For the fPVC/MHEPE composite, a compact and continuous char residue formed, which could inhibit heat and flammable volatile migration between the matrix and burning zones. In the gas phase, the dilution effect of H2O vapor reduced the concentrations of O2 and flammable volatiles. The free‐radical quenching effect of ·PO and ·PO2 also played a vital role in extinguishing flame and terminating combustion. Further, the introduction of EPE improved the tensile and impact strengths of the fPVC/MH composites because of the excellent interfacial compatibility between MHEPE and the fPVC matrix. This study provides a simple and workable solution for the trade‐off dilemma, and the remarkable flame retardancy and mechanical properties of the fPVC/MHEPE composite render it a promising cable material. [ABSTRACT FROM AUTHOR]

Spent adsorbents used in As removal treatment may re-leach As. In this study, the effects of soil on spent Mg-based and Ca-based adsorbents were investigated. The spent adsorbents containing arsenite (As(III)) were prepared by adsorbing As(III) on MgO, Mg(OH)2, CaO, and Ca(OH)2 powder reagents. Kuroboku soil (Ku), yellow-brown forest soil (YF), Kanuma soil (Ka), river sand (RS), and mountain sand (MS) were used as soil samples. The As leaching ratio was examined in coexistence with soil via shaking tests, and the results were compared with those of a previous study on adsorbents containing arsenate (As(V)). The environmental stability of the spent adsorbents was found to vary greatly depending on the combination of the As valence, adsorbent type, and soil type. However, regardless of the adsorbent or soil type, the spent adsorbents containing As(III) were more likely to leach As than those containing As(V). Additionally, the As leaching ratio was generally lower in Ku and YF and higher in Ka, RS, and MS. For environmentally friendly and sustainable As removal treatment, disposal, and management, the selection of MgO as the adsorbent and treatment involving the oxidation treatment of As(III) to As(V) before adsorbing As onto adsorbents are recommended. [ABSTRACT FROM AUTHOR]

For the optimization of the process of preparing flaky magnesium hydroxide by electrodeposition, a multi ‐ physics coupling method was used to simulate the two ‐ dimensional unsteady state of magnesium hydroxide preparation by electrodeposition. The voltage, current density, electrolyte flow field, and gas distribution of the electrolyte are obtained under different plate spacing and plate placement depths. The effect of plate parameters on the electric and flow fields during electrolytic cell operation was analyzed. The research results show that the cell voltage decreases when the plate placement depth is reduced. However, reduced plate placement depth hinders electrolyte fluidity, which is detrimental to the reaction. Reducing the plate spacing can enhance mass transfer and reduce the working voltage, but it also worsens the uniformity of the chemical reaction distribution on the plates. To achieve faster electrolyte flow, lower cell voltage, and more uniform current distribution, the plate placement depth should be increased as much as possible, and the plate spacing should be adjusted appropriately. [ABSTRACT FROM AUTHOR]

In order to improve the flame retardancy of polypropylene/magnesium hydroxide (PP/MH) composites and to grasp the intensity of different influencing factors on the flame retardancy of the materials, the MH particle size, contact angle, and the amount of additive were used as the three inputs, and the limiting oxygen index (LOI) of PP/MH composites was taken as the output. A three-layer BP neural network prediction model was established, and the orthogonal test results were used as samples to train it to predict the flame retardancy of the composites. The prediction results were verified by experiments. The results show that the effects of various factors on the flame retardancy of the PP/MH composites from large to small are MH content, MH contact angle and MH particle size. The optimal process parameters: the MH particle size is 0.2 µm, the MH contact angle is 135°, the MH content is 40%. Under these conditions, the LOI of PP/MH composite is as high as 31.5%. The BP neural network model can accurately predict the flame retardancy of composites, and the relative error between the predicted value and the experimental value is generally less than 5%. The prediction model of flame retardancy can be used to optimize the performance of materials, reduce the experimental workload, and improve the work efficiency. [ABSTRACT FROM AUTHOR]

In order to explore a wider range and lower cost of raw materials for the preparation of magnesium silicate hydrate (M-S-H), an acid-leaching method was employed to extract and separate high-purity magnesium hydroxide (Mg(OH)2) with a purity higher than 97% and amorphous silica with a purity higher than 90% from four types of natural silicate minerals (serpentine, peridotite, zeolite, and montmorillonite). These two intermediate products, which are amorphous silica and magnesium hydroxide, were used to prepare M-S-H, and the influence of curing at two temperatures, 50 °C and 80 °C, on the properties of M-S-H was investigated. The results showed that with the increase in curing temperature, the bound water content, tetrahedral polymerization degree, and Mg(OH)2 content increased. There was a good correlation between the increase in strength and the bound water content of M-S-H. This work provides a possible technological route for expanding the raw materials for preparing magnesium silicate hydrate cementitious materials and utilizing the abundant magnesium silicate minerals in the Earth's crust. [ABSTRACT FROM AUTHOR]

Copyright of Inorganic Chemicals Industry is the property of Editorial Office of Inorganic Chemicals Industry 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.)

In order to systematically study the suppression effect of Aluminum hydroxide[Al(OH)3] and Magnesium hydroxide[Mg(OH)2] on the explosion of flour, Hartmann experiment system was used to carry out the explosion flame propagation experiment, and the influence of adding different proportions of Al(OH)3 and Mg(OH)2 powder on the morphology and propagation speed of flour combustion flame was studied. Combined with the thermogravimetric analysis (TG) and differential scanning calorimetry (DSC) curves of Al(OH)3 and Mg(OH)2 powder, the inhibition mechanism of Al(OH)3 and Mg(OH)2 powder on flour explosion was analyzed. The results showed that with the increase of Al(OH)3 and Mg(OH)2, the flame propagation speed gradually decreases. After adding 40%wt Mg(OH)2, when t = 182 ms, the flame reaches the top of the glass tube. When 60 wt% Mg(OH)2 and 60 wt% Al(OH)3 powder were added, the maximum flame propagation velocity of flour decreased from 13.86 m/s to 5.78 m/s and 1.62 m/s, respectively, and Al(OH)3 was superior to Mg(OH)2 in inhibiting flame propagation. Both inhibitors can inhibit flour combustion by adsorption of H and OH radicals. [ABSTRACT FROM AUTHOR]

The structural features of halide varieties in an analogous series of double compounds of aluminum and lithium are studied. The possibility of transition of a bromine-containing version of the double compound of aluminum and bromine into a lithium concentrate is shown. Methods are found for preparing a lithium concentrate without bromine admixture. After bromine is industrially removed, the resulting lithium concentrate is used to obtain the following lithium products: lithium carbonate and lithium hydroxide monohydrate. In an integrated scheme, magnesium hydroxide after separating bromine and lithium products is precipitated to produce a calcium chloride solution. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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Aluminium metal foams offer low density (∼10–15% of bulk material) possessing cellular structure that ensures unique features with high stiffens, better energy absorption, thermal and acoustic properties. Selection of different foaming agents for preparing AA6061 foam samples are indeed an industrial relevance for better control over porosity and its dimensions, strengths (tensile, flexural and compression) useful for distinguished applications. Three foaming agents such as wax powder, magnesium hydroxide, and titanium hydride are selected with varying 3–9 weight percentage to prepare metal foams viz. powder metallurgy technique. For the prepared foam samples the percentage porosity, pore dimensions (maximum pore size, and equivalent diameter) and strengths were examined. Wax powder foaming agent resulted with a maximum strength in foam samples compared to magnesium hydroxide and titanium hydride. Scanning electron microscope with energy dispersive spectroscopy analysis revealed that there is no evidence of foreign elements and confirm uniform distribution of porosity in the foam samples. [ABSTRACT FROM AUTHOR]

This work deals with the synthesis, characterization of hybrid ethylene propylene diene monomer (EPDM) composites loaded with nano‐boron nitride (nano‐BN)/nano‐titanium dioxide (nano‐TiO2) and micro Mg(OH)2 particles for its suitability towards high‐voltage insulation application. The elastomer samples were prepared by carefully dispersing the micro and nano fillers during the mastication process of EPDM polymer using a two roll mill, followed by vulcanization. The samples were characterized for mechanical, morphological, thermal, and electrical insulation properties. The highest tensile strength among the composite samples was noted for 1 phr nanoparticles loaded samples. Fourier Transform Infrared (FTIR) results show no change in the chemical moiety upon addition of nano‐BN/nano‐TiO2 in EPDM composites. Enhancement in hydrophobicity is observed for 3 phr nano‐TiO2 loaded composites, which shows a maximum static contact angle of 110°. Meanwhile remarkable enhancement in the thermal conductivity and volume resistance of the composites are contributed to the addition of nano‐BN, thereby achieving maximum dielectric breakdown voltage (i.e., ~21 kV/mm for EMB3). Scanning electron microscope images and atomic force microscopy (AFM) topography highlight that low concentration (i.e., 1 phr) based composites have homogeneous dispersion in matrix and excessive nano filler addition deteriorates properties by forming filler aggregates and increasing surface roughness. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) is one of the most concerned emerging pollutants in recent years. Its widespread distribution has been shown to have potentially adverse effects on human health and ecosystems. Therefore, in this study, magnetic magnesium hydroxide coagulant (MMHC) was prepared by adding Fe3O4 magnetic micron particles in the Mg(OH)2 generation process, and it was used with PAM, a polymer flocculant, to remove polyethylene microplastics (≤270 μm) from water by coagulation. The removal efficiency of microplastics by MMHC reached 87.1%, which was 14.7% higher than that of traditional magnesium hydroxide coagulant (MHC). However, the Zeta potential of MMHC was lower than that of MHC, only 17.3 mV. In addition, the surface morphology of MMHC showed bubble-like clusters. The effect of PAM adding time on the microplastic removal efficiency was investigated. The best adding time of non-ionic PAM was 15s before the slow mixing started. The removal efficiency of organic matter and suspended particles in water by MMHC was determined by turbidity, ultraviolet spectrophotometry and three-dimensional fluorescence. The maximum removal efficiency was 98.5% and 93.3%, respectively. With the increase of the concentration of humic acid and kaolin in water, the removal efficiency of microplastics was basically not affected. MMHC can be reused after recycle, but it was found that the electrical neutralization mechanism was affected due to the transformation of its Zeta potential, and the adsorption effect of humic acid and kaolin particles in water became worse, the removal efficiency of microplastics, turbidity and UV254 decreased to 20.2%, 17.5% and 30%, respectively. [ABSTRACT FROM AUTHOR]

Using alkali pretreatment can effectively remove residual variable-valence metals from non-metallic powder (WPCBP) in waste printed circuit boards. However, substantial amounts of waste lye are generated, which causes secondary pollution. On this basis, this study innovatively utilized waste alkali lye to prepare nano-magnesium hydroxide. When the dispersant polyethylene glycol 6000 was used at a dosage of 3 wt.% of the theoretical yield of magnesium hydroxide, the synthesized nano-magnesium hydroxide exhibited well-defined crystallinity, good thermal stability and uniform particle size distribution, with a median diameter of 197 nm. Furthermore, the in situ method was selected to prepare WPCBP/Mg(OH)2 hybrid filler (MW) and the combustion behavior, thermal and mechanical properties of PP blends filled with MW were evaluated. The combustion behavior of the PP/MW blends increased with the increasing hybrid ratio of Mg(OH)2, and the MW hybrid filler reinforced PP blends showed better thermal and mechanical properties compared to the PP/WPCBP blends. Furthermore, the dynamic mechanical properties of the PP/MW blends were also increased due to the improved interfacial adhesion between the MW fillers and PP matrix. This method demonstrated high economic and environmental value, providing a new direction for the high value-added utilization of WPCBP. [ABSTRACT FROM AUTHOR]

Understanding the impact that mineral grain size and seawater salinity have on magnesium hydroxide (Mg(OH)2) dissolution and secondary calcium carbonate (CaCO3) precipitation is critical for the success of ocean alkalinity enhancement. We tested the Mg(OH)2 dissolution kinetics in seawater using three Mg(OH)2 grain sizes (<63, 63–180 and >180 µm) and at three salinities (~36, ~28 and ~20). While Mg(OH)2 dissolution occurred quicker the smaller the grain size, salinity did not significantly impact measured rates. Our results also demonstrate that grain size can impact secondary CaCO3 precipitation, suggesting that an optimum grain size exists for ocean alkalinity enhancement (OAE) using solid Mg(OH)2. Of the three grain sizes tested, the medium grain size (63–180 µm) was optimal in terms of delaying secondary CaCO3 precipitation. We hypothesize that in the lowest grain size experiments, the higher surface area provided numerous CaCO3 precipitation nuclei, while the slower dissolution of bigger grain size maintained a higher alkalinity/pH at the surface of particles, increasing CaCO3 precipitation rates and making it observable much quicker than for the intermediate grain size. Salinity also played a role in CaCO3 precipitation where the decrease in magnesium (Mg) allowed for secondary precipitation to occur more quickly, similar in effect size to another known inhibitor, i.e., dissolved organic carbon (DOC). In summary, our results suggest that OAE efficiency as influenced by CaCO3 precipitation not only depends on seawater composition but also on the physical properties of the alkaline feedstock used. [ABSTRACT FROM AUTHOR]

In this study, for magnesium hydroxide adsorbents, hydrothermal doping strategies were used to change their surface and structural properties to enhance adsorption. A novel adsorbent was prepared and used to remove low concentrations (<100 mg ⋅ L−1) of Pb2+ from water. The structure of the adsorbent was characterized a series of characterization methods with X‐ray diffraction, scanning electron microscopy, thermogravimetric analysis, fourier transform infrared spectroscopy, nitrogen adsorption‐desorption isotherms, and X‐ray photoelectron spectroscopy. The results showed that the adsorbent was a whisker composed of magnesium hydroxide, carbonized chitosan and basic magnesium carbonate (BMC@Mg(OH)2/CCS) with a specific surface area of 84.35 m2 ⋅ g−1, much higher than that of pure magnesium hydroxide whisker (37.84 m2/g). The adsorption isotherm, kinetic, and thermodynamic properties of the adsorbent for lead ions were studied in detail by batch adsorption. The Langmuir model fits the adsorption isotherm better, and the adsorption capacity is 416.67 mg ⋅ g−1. The adsorption mechanism, which mainly involves chemical precipitation and ligand chelation, is discussed. [ABSTRACT FROM AUTHOR]

China's salt lakes contain an abundance of magnesium resources as high-magnesium brine, a by-product of potash fertiliser production is often discharged into salt lakes, causing environmental damage. Magnesium oxide from salt-lake brine can be used to produce magnesium oxychloride cement (MOC), but the calcium impurities present in salt lakes affect the properties of MOC. To investigate the effects of these impurities, magnesium oxide was produced by calcining a magnesium hydroxide precursor. By adding calcium hydroxide or calcium chloride, the incorporated calcium impurities were 0, 5 and 10% by mass of magnesium oxide. The compressive strength, heat of hydration, composition of the hydration product phases and the pore structure development of MOC samples were evaluated. It was found that Ca2+ ions increased the early strength and the rates of setting and hardening of the MOC. However, the presence of calcium impurities did not change the hydration phase composition. This is primarily because the Ca2+ ions promoted the participation of magnesium oxide in the hydration reaction and enhanced the early strength of the MOC. The findings of this study demonstrate the technical feasibility of utilising magnesium resources from salt lakes to prepare magnesium oxide and apply it in the production of MOC. [ABSTRACT FROM AUTHOR]

Thermally conductive and flame-retardant polyolefin composites are facing great challenges in meeting the increasing demands for fire safety and thermal management. Aiming at simultaneously enhancing thermal conductivity and flame retardancy, hexagonal boron nitride (hBN) and magnesium hydroxide (MH) were adopted in ethylene–vinyl acetate copolymer/polyolefin elastomer (EVA/POE) blends to design composites with selective filler distributions and co-continuous networks via different processing schemes. The thermal conductivity and flame retardancy show strong dependence on the distributed structure of hBN and MH. The composites with hBN-rich centers and MH-rich edges in the filled POE phase show a thermal conductivity of 0.70 W/(m·K) and an LOI of 27.7%, which are very close to the thermal conductivity of EVA/POE/hBN and the LOI of EVA/POE/MH at the same total filler content. The composites with MH-rich centers and hBN-rich edges show pHRR, THR and TSP values of 169 kW/m2, 49.8 MJ/m2 and 1.8 m2, which are decreased by 40%, 33% and 62% in comparison with EVA/POE/MH, respectively. Modulating the filler structure distribution provides a strategy to co-enhance thermal conductivity and flame retardancy. [ABSTRACT FROM AUTHOR]

Magnesium (Mg) is one of the promising metal fuels used in various applications such as flares, propellants, and rocket motor igniters. In particular, Mg is often used in the form of compounds or mixtures rather than being used alone. However, Mg is vulnerable to moisture, requiring an extra care in storage. Magnesium–Teflon–Viton (MTV), one of Mg-based mixtures, is expected to lose its combustion performance when exposed to moisture. The relative humidity (RH) conditions gave rise to the formation of an oxide film composed of magnesium oxide (MgO) and magnesium hydroxide (Mg(OH)2), while Mg(OH)2 was decomposed into MgO during the melting of polytetrafluoroethylene (Teflon). The dry conditions resulted in the formation of an oxide film composed only of MgO, which did not affect the melting of Teflon as in the RH condition. Moreover, a high-temperature environment intended for accelerated aging disrupted both pre-ignition and subsequent thermal reaction of MTV. Thus, the present work identified the changes in the thermochemical characteristics of MTV and clarified the roles of heat and moisture during such hygrothermal aging. [ABSTRACT FROM AUTHOR]

The morphology of the material has a great influence on its flame retardancy. In order to study the effects of magnesium hydroxide with different morphologies on the flame retardancy of epoxy resin, magnesium chloride and magnesium sulfate were used as raw materials to prepare magnesium hydroxide with rod, flake and flower, and were added to epoxy resin to prepare epoxy resin composite to explore the flame retardancy and the flame retardant mechanism. The results show that the diameter of rod magnesium hydroxide ranges from 250 nm to 500 nm and the length is about 5 μm. The flaky magnesium hydroxide has a hexagonal sheet structure with a size of 100 nm. The size of flower ball magnesium hydroxide is 1~2 μm. When the addition of magnesium hydroxide is 3%, the flame retardancy of epoxy resin is improved as: flake>flower>rod. Compared with pure epoxy resin, the addition of flaky magnesium hydroxide reduceds the TSP by 35.1%, the PHRR by 36.6%, and the PCOP by 39.4%. The research provides the direction for the application of magnesium hydroxide in polymers. [ABSTRACT FROM AUTHOR]

In this study, arsenate, As(V), and fluoride (F) were simultaneously removed from contaminated water using MgO, Mg(OH)2, and MgCO3 as Mg-based adsorbents, as existing studies only focus on their individual removal. The removal performance of As(V) and F followed the order MgCO3 < Mg(OH)2 < MgO. Under the test conditions, MgO and Mg(OH)2 met the environmental standards for As and F (0.01 and 0.8 mg/L, respectively), but MgCO3 did not. The As(V) removal performance was not significantly affected by an increase in the initial F concentration. It was concluded that As(V) was adsorbed and removed more preferentially than F by Mg-based adsorbents because a considerable amount of F remained even when the majority of As(V) was removed. Most arsenic (As)-adsorption data for MgO fit the Langmuir and Freundlich models, whereas those for Mg(OH)2 did not fit either model well. Additionally, the As-adsorption data for MgCO3 fit the Freundlich model but not the Langmuir model. Most of the F-adsorption data for the Mg-based adsorbents fit the Langmuir and Freundlich models. The removal mechanisms of As(V) and F using Mg-based adsorbents were assumed to be predominantly caused by ion-exchange and chemical-adsorption reactions on the adsorbent surface because no magnesium arsenate, magnesium fluoride, or magnesium hydroxide fluoride species were observed in the X-ray diffraction analysis. This research advances the sustainable As–F simultaneous treatment method using inexpensive adsorbents. [ABSTRACT FROM AUTHOR]

Natural impurities such iron, sulphates, chlorides, and heavy metals that cannot be removed by recrystallization are present in the magnesia that is formed. One method for making magnesium perchlorate includes combining per chloric acid and magnesite dust, a process that generates a lot of heat and hydrogen gas during the reaction. Magnesite is leached using an aqueous per chloric acid solution with a 500 rpm stirring speed. The following factors were taken into account in this study: fluctuation in leaching temperature (°K), per chloric acid volume percentage, and time of leaching. Magnesium perchlorate recovery is 97.3% with a temperature increase to 333.15 K and 100% with an increase in leaching time to 1 h. Dehydration of magnesium chloride was tried through thermochemical processing with several compounds and the results are not encouraging. Experimental studies have also been carried out on the electrochemical preparation of magnesium hydroxide from magnesium chloride. [ABSTRACT FROM AUTHOR]

High fire‐resistance polypropylene (PP) composites were prepared by using environment‐friendly flame retardants including expandable graphite (EG), red phosphorus (RP), and magnesium hydroxide (MH). Synergism between EG, RP, and MH on the thermo‐oxidation behavior and flame resistance of PP was found. The incorporation of MH and RP formed highly thermally stable mixtures of magnesium phosphates consisting of Mg3(PO4)2, Mg(PO3)2, and α‐Mg2P2O7 at both amorphous and crystalline phases in the burning process. The mixture not only covered the surface of burning materials but also could reinforce the char structure of the PP/EG composites, thereby significantly enhancing the condensed phase flame retardant mechanism of the composites. Mass ratios of the flame retardants were also optimized to obtain the composite with the highest flame retardant efficiency. The result revealed that the combination of EG, RP, and MH in PP at MH/RP mass ratio of 3/2 with only a total additive content of 18 wt.% could make its limiting oxygen index (LOI) increase from 16.8% to 27.2% and the UL‐94 rating was improved from none to V‐0. In addition, the mechanical properties of the composites were improved via the surface treatment of MH and RP with calcium stearate and silicone oil, respectively. [ABSTRACT FROM AUTHOR]