Magnesium Chloride Research Articles

Salt Deposits and Brine Blowout: Development of a Cross-Linking Composition for Blocking Formations and Methodology for Its Testing

Uncontrolled inflow of formation fluid (brine) into a well adversely affects the cation–anion bonds in solutions and leads to their dissociation and loss of aggregative stability. Blow-out significantly complicates the drilling process and leads to an increase in non-productive time and in financial costs for problem solving. It is necessary to create a blocking screen that allows separation of the layer from the well and prevents brine flow. This article is devoted to the development of polymeric-blocking compositions that work due to the crystallization reaction of divalent salts of calcium and magnesium chlorides. More than 14 components were detected in the formation fluid on the atomic emission spectrometer. Based on the study of the compatibility of components with brine and the study of rheology and filtration processes through a real core under HPHT conditions, the optimal component polymer composition was selected. The reason for the increase in the rheology of composition during its thickening was established. With the help of tomographic studies, the depth of penetration of the filtrate into the core of layers was determined. For further studies, an experimental stand was designed for physical simulation of the isolation process under HPHT conditions and backpressure from the formation.

Factors Impacting Atmospheric Pitting Morphologies

Stainless steels exposed to marine and near-marine environments can suffer from localized corrosion due to the appreciable amount of chloride aerosols present. In some cases, this localized corrosion, in the presence of sufficient tensile stress, can lead to stress corrosion cracking (SCC). Spent nuclear fuel (SNF) is currently stored in stainless steel canisters at independent spent fuel storage installation sites (ISFSI), many of which are located in near-marine environments. The possibility of localized corrosion features transitioning to SCC is a potential concern, particularly as the use of the SNF canisters at ISFSIs has been extended beyond their original licensing period.There is evidence that the likelihood of this transition occurring is dependent on the morphology of corrosion damage. Therefore, it is important to examine factors impacting the corrosion morphology. This work focuses on the effects of environment, surface finish, and stress state.304L stainless steel u-bends of various surface finishes were deposited with fine droplets of magnesium chloride solution or artificial sea water. They were divided among several exposure environments, cyclic or static in nature. Flat coupons of 304H, 304L, or 316L were finished to the same surface roughnesses and exposed in the cyclic environment. Static exposures were 75% or 40% RH at an elevated temperature while the cyclic environment varied both temperature and relative humidity. The cyclic environment is designed to mimic diurnal cycles experienced on a warm SNF canister after an initial storage (or cooling) period. In the flat coupons, the roughest surface finish developed elongated pits and microcracks formed along the edges of the pits, largely running perpendicular to the grind lines. When viewed in cross-section, pits on the roughest surface finish also appeared to have more severe under-cutting and to be more irregularly shaped. The results of the flat coupons will be compared to the u-bends exposed with various salt types and stress states. SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525. SAND2022-4056 A. PNNL-SA-171827

The Effects of Sulfate on the Parameters for Maximum Pit Size Calculations on Stainless Steel 316L

Dry storage canisters that contain radioactive waste containers in the United States are typically made of stainless steel such as 316L. The longevity of such canisters put into service around forty years ago is a primary concern to the United States Department of Energy. Due to their location, many of these canisters undergo fluctuations in relative humidity and temperature, as well as an accumulation of deliquescent salts on their surface. The nature of the anions present in these salts establishes whether or not proper conditions for pit propagation exist. In order to predict these canisters’ maximum pit size, computational models that employ input parameters on the pit kinetics can be utilized. Such kinetic parameters are the critical pit stability product (i·x)crit and the repassivation potential (Erp), as they are key to the anodic current demand in a pit and the cathodic current supply outside a pit, respectively. Previous models that focused on the effect of chloride concentrations on the maximum observed pit size have shown to be overly conservative. Therefore, to increase the accuracy of the model, a more complex solution that contains inhibiting ions, such as sulfates, should be considered. In this study, artificial 1-D pit electrochemical experiments were carried out in a 50.8μm diameter SS316L wire exposed to solutions containing different concentrations of magnesium chloride (MgCl2) and magnesium sulfate (MgSO4). Maximum pit size calculations were performed utilizing the kinetic parameters obtained from these experiments. A theoretical model that seeks to describe the formation and growth of a complex salt film precipitate at the bottom of the pit is presented as well.

Photocatalytic Degradation of Organic Dyes Using Titanium Dioxide (TiO2) and Mg-TiO2 Nanoparticles

Titanium dioxide (TiO2) based nano-sized photocatalysts (NPCs) were synthesized following a green method from the extract of Peepal (Ficus religiosa) leaves and titanium tetrachloride as precursors. Doping of TiO2 with Magnesium (Mg) was done using magnesium chloride through the method of chemical precipitation.

Utilizing Nano Silica to Reduce Calcium Oxychloride Formation in Cementitious Materials

This paper examines the use of two nano silica (NS) materials as an additive that can reduce the susceptibility of concrete to deicing salt damage. The motivation for this research is to evaluate whether NS can be used to improve resistance to calcium oxychloride formation because of deicing salts. Deicing salts, like calcium chloride and magnesium chloride, can react with water and calcium hydroxide in concrete to form an expansive product called calcium oxychloride. This work builds on previous observations that supplementary cementitious materials (SCMs), such as Class F fly ash, slag, and silica fumes, can reduce calcium oxychloride formation through dilution of the cement, which results in a reduction in calcium hydroxide and the pozzolanic reaction, which further reduces calcium hydroxide through chemical reaction. This paper investigates whether NS additions during the mixing process can provide similar results to other SCMs. Both NSs had the same particle size distribution and specific surface area, but NS2 had alumina on the surface while NS1 did not. Toward this end, the calcium hydroxide content and calcium oxychloride were measured using thermal gravimetric analysis and low-temperature differential scanning calorimetry, respectively. The addition of NS to a mixture was found to reduce the calcium oxychloride at lower dosages as compared to Class F fly ash.

Precipitated Calcium Carbonate Derived from Green Mussel Shells Extracted from Magnesium Chloride Containing Solution

Green mussel shells are one of the calcium carbonate-rich biogenic sources. They contain 95.7 to 98.2 wt. % calcium. The high calcium content of green mussel shells was extracted and converted into calcium oxide material in the study by calcination at 900°C for 5 h. Later, at stirring times of 30, 60, 90, and 120 minutes, a solution medium containing magnesium chloride was used to dissolve the resulting calcination powder and subsequent carbonation for producing PCC (precipitated calcium carbonate). According to XRD, Rietveld, and FTIR analyses, the resulting PCC product with calcite-containing Mg was obtained primarily for a short stirring time of 30 minutes during the carbonation process, whereas calcite and aragonite were generated at longer stirring times (from 60 to 90 minutes). Instead, brucite was obtained after 120 minutes of stirring. The PCC product has a non-uniform polyhedrallic morphology of various small and large sizes as observed by SEM. This powder processing method allowed for faster PCC synthesis at a lower cost while requiring no chemical addition to increase basicity.

Manufacturing high-performance formcoke from pulverized coal using potato residue-based biomass binders

Formcoke is a more favorable and cleaner fuel than coal because of its high carbon content, high calorific value, and low ash content. The identification and sourcing of high-performance, cost-effective, and green binders for formcoke production from pulverized coal are required but remain a big challenge. Herein, potato residue was composited with magnesium chloride as a bio-based composite binder for the production of high-performance formcoke. The compression strength of the obtained formcoke was determined as 1967 N. The calorific value of the formcoke was in the same range as lumpy coal. Furthermore, the formcoke exhibited higher thermal stability and required more activation energy in the combustion process than briquette coal and pulverized coal. In addition, the pollutant emissions of the formcoke such as carbon dioxide, sulfur dioxide, hydrocarbons, and other pollutants of the combustion process were significantly less than those of pulverized coal. This research uses potato residue as the primary raw material to prepare a bio-based composite binder for the production of high-performance formcoke with the advantages of a simple manufacturing process, abundant availability, low price, and excellent performance. It provides a new application of potato residue and a high-performance binder preparation method for the production of high-performance formcoke.

Effects of probiotic and magnesium co-supplementation on mood, cognition, intestinal barrier function and inflammation in individuals with obesity and depressed mood: A randomized, double-blind placebo-controlled clinical trial.

BackgroundThe co-occurrence of obesity and mood impairments named as “metabolic mood syndrome” (MMS) is often neglected in the obesity management. This study aimed to evaluate effects of Probio-Tec ®BG-VCap-6.5 and magnesium co-supplementation on mood, cognition, intestinal barrier function and serum C reactive protein (CRP) levels in participants with obesity and depressed mood.DesignSeventy-four eligible participants were randomly allocated to either Probio-Tec®BG-VCap-6.5 [containing Lactobacillus rhamnosus (LGG®) and Bifidobacterium animalis subsp. Lactis (BB-12®)] + Magnesium chloride or placebo for 9 weeks. Sociodemographic data were collected in the beginning. Anthropometric, dietary and physical activity (PA) assessments were carried out. Beck Depression Inventory-II (BDI-II) and Montreal Cognitive Assessment (MoCA) scores were assessed through validated questionnaires. Fasting plasma zonulin, lipopolysaccharide (LPS) and (CRP) were measured by ELIZA kits.ResultsOf seventy-four participants (mean age 37.51 ± 8.10), 52 completed the study. Changes in serum LPS and zonulin were not different significantly between groups (−3.04 ± 44.75 ng/dl, 0.11 ± 5.13, ng/dl, p > 0.05 for LPS and 1.40 ± 48.78 ng/dl, −0.17 ± 6.60, p > 0.05 for zonulin, respectively). CRP levels reduced significantly in intervention group compared to placebo [−474.75 (−1,300.00, −125.00) mg/l vs. 175.20 (−957.75, 1,683.25) mg/l, p = 0.016]. Changes in BDI-II and MoCA scores were not significantly different between intervention (−7.13 ± 5.67, 1.20 ± 2.16, respectively) and placebo (−5.42 ± 6.71, 1.94 ± 1.86, respectively) groups (p > 0.05).ConclusionNine weeks of probiotic and magnesium co-supplementation resulted in decreased CRP levels as an indicator of inflammatory state with no significant effects on mood, cognition and intestinal integrity in individuals with obesity and depressed mood.

Magnesium Potentiates the Vortioxetine's Effects on Physical Performances and Biological Changes in Exercise-Induced Stress in Rats.

Background and objectives: Vortioxetine (VRT) is a relatively new selective serotonin reuptake inhibitor (SSRI) antidepressant and serotonin receptor modulator, approved for the treatment of major depression and generalized anxiety disorder. Depression has been linked with psychomotor disengagement, oxidative stress burden and decreased blood levels of brain-derived neurotrophic factor (BDNF). In our study we performed the experimental investigation of VRT, magnesium and of their association on the rats’ endurance capacity, motor behavior and blood biological disturbances in rats subjected to forced exercise in treadmill test. Materials and Methods: The substances were administered orally for 14 consecutive days, as follows: group 1 (control): distilled water 0.3 mL/100 g body; group 2 (Mg): magnesium chloride 200 mg/kg body; group 3 (VRT): VRT 20 mg/kg body; group 4 (VRT+Mg): VRT 20 mg/kg body + magnesium chloride 200 mg/kg body. Magnesium was used as positive control substance with known effects in treadmill test. The consequences of VRT treatment on glucose, cortisol, BDNF and oxidative stress biomarkers (superoxide-dismutase, malondialdehyde, glutathione-peroxidase, lactate dehydrogenase) were also assessed. Results and conclusions: The use of VRT resulted in an improvement in motor capacity and an increase of the rats’ endurance to physical effort. The administration of VRT increased the serum BDNF levels and reduced the oxidative stress in rats subjected to physical effort. The association of magnesium potentiated the effects of VRT on physical performances, the antioxidant activity and the decreasing in serum stress markers in treadmill test in rats.

Hierarchical porous nitrogen-doped carbon supported MgO as an excellent composite for CO2 capture at atmospheric pressure and conversion to value-added products

The recent climate change is causing widespread concern around the world. Since anthropogenic CO2 emissions are recognized as a major contributor to this alarming phenomenon. As a result, there is an urgent need to reduce the carbon footprint and eliminate excess carbon dioxide from the atmosphere. Carbon capture, utilization, and storage are currently the most promising solution to solve this problem. This study reports a simple method for producing a novel hierarchical porous nitrogen and carbon supported MgO material (N@MgO/C) from the abundant bio-waste and magnesium chloride. The topographies of the prepared samples were thoroughly examined by several characterization techniques. The XRD, Raman, and XPS analyses reveal the existence of graphitic carbon. FESEM, and N2 adsorption-desorption studies, reveal a hierarchical porous structure with a mesoporous texture and good surface area (258.98 m2/g). Furthermore, N@MgO/C demonstrated an excellent ability to adsorb CO2 at room temperature with maximum adsorption of 2.55 mmol/g remaining almost stable up to 4 cycles. Moreover, it exhibits good catalytic activity for the cycloaddition of CO2 with various epoxides at atmospheric pressure in the presence of CTAB under the solvent-free condition with a yield of 96% and high stability over five cycles without any modification in its morphology.

Induction of the Prenylated Stilbenoids Arachidin-1 and Arachidin-3 and Their Semi-Preparative Separation and Purification from Hairy Root Cultures of Peanut (Arachis hypogaea L.).

Prenylated stilbenoids such as arachidin-1 and arachidin-3 are stilbene derivatives that exhibit multiple pharmacological activities. We report an elicitation strategy using different combinations of cyclodextrin, hydrogen peroxide, methyl jasmonate and magnesium chloride to increase arachidin-1 and arachidin-3 production in peanut hairy root cultures. The treatment of hairy root cultures with cyclodextrin with hydrogen peroxide selectively enhanced arachidin-1 yield (132.6 ± 20.4 mg/L), which was 1.8-fold higher than arachidin-3. Similarly, cyclodextrin combined with methyl jasmonate selectively enhanced arachidin-3 yield (178.2 ± 6.8 mg/L), which was 5.5-fold higher than arachidin-1. Re-elicitation of the hairy root cultures further increased the levels of arachidin-1 and arachidin-3 by 24% and 42%, respectively. The ethyl acetate extract of the culture medium was consecutively fractionated by normal- and reversed-phase column chromatography, followed by semi-preparative HPLC purification on a C18 column to yield arachidin-1 with a recovery rate of 32% and arachidin-3 with a recovery rate of 39%, both at higher than 95% purity. This study provided a sustainable strategy to produce high-purity arachidin-1 and arachidin-3 using hairy root cultures of peanuts combined with column chromatography and semi-preparative HPLC.

Coupled effect of organic fouling and scaling in the treatment of hyper-saline produced water using forward osmosis

Hyper-saline water streams, such as the produced water from the oil industry, cannot be treated via the conventional desalination method, such as reverse osmosis (RO), due to the extreme required pressure to overcome the osmotic pressure. This research investigates the effect of oil fouling and cleaning behaviors when the forward osmosis (FO) process is applied to treat hyper-saline-produced water. Synthetic produced water with total dissolved solids (TDS) concentration of 240 g/l (contained Na, Ca, Mg, Fe, Cl, SO4, and CO3 ions) and oil content of 100 ppm was used as a feed solution. Also, two draw solutions, namely: ammonium bicarbonate (NH4HCO3) and magnesium chloride (MgCl2) of concentrations 6 M and 4.8 M, respectively, were utilized for the FO operation. Results showed that the MgCl2 draw solution provided significantly higher water flux than NH4HCO3 due to MgCl2’s high osmotic pressure and low scaling influence. Furthermore, the individual impact of oil was found to be low on the FO’s water flux. However, a synergistic effect between the oil and inorganic scaling was noticed. SEM technique was used to comprehend the observation and analyze the fouling content. Although the feed was a highly polluted stream, it was found that osmotic backwashing can recover more than 90% of the initial flux.

Stabilisation of a clay soil by injection of different ions

In this research study the effects of calcium and magnesium ions on stabilisation of a clay soil were studied by conducting a set of laboratory tests. A special apparatus was employed for carrying out the tests under constant voltage and time. During the tests, solutions of calcium chloride (CaCl2) or magnesium chloride (MgCl2) with different concentrations were injected into the soil samples. The electro-osmotic and electrokinetics methods were used for stabilisation of the soil and the results were compared with each other. In the electro-osmotic technique, distilled water was used as pore fluid, but in the electrokinetic method, calcium chloride or magnesium chloride solutions with various concentrations were injected into the pores of soil samples. The results revealed an increase in strength of the soil in both methods. In the electrokinetic method, the amount of increase in strength was a function of concentration of the solution that was used. The results also indicated that a solution of calcium chloride is more effective in increasing the strength, discharge flow and electro-osmotic permeability than a magnesium chloride solution at various concentrations. In addition, the variations of these properties are a function of the concentration of the given solution.

A pilot investigation of the efficacy and safety of magnesium chloride and ethanol as anesthetics in Loligo vulgaris embryos.

The inclusion of cephalopods in the legislation related to the use of animals for experimental purposes has been based on the precautionary principle that these animals have the capacity to experience pain, suffering, distress, and lasting harm. Recent studies have expanded this view and supported it. Handling cephalopod mollusks in research is challenging and whenever more invasive procedures are required, sedation and/or anesthesia becomes necessary. Therefore, finding adequate, safe, and effective anesthetics appears mandatory. Several substances have been considered in sedating cephalopods, in some instances applying those utilized for fish. However, species-specific variability requires more detailed studies. Despite long-lasting experience being linked to classic studies on squid giant axons, evidence of action on putative anesthetic substances is scarce for Loligo vulgaris and particularly for their embryos. The aim of the current study was to evaluate effects elicited by immersion of squid embryos in anesthetic solutions and examine whether these forms display a similar reaction to anesthetics as adults do. Different concentrations of ethanol (EtOH; 2, 2.5, and 3%) and magnesium chloride (MgCl2; 1, 1.5, and 1.8%) were tested by adopting a set of indicators aimed at exploring the physiological responses of squid embryos. Forty-two embryos of the common squid Loligo vulgaris (stages 27-28) were assigned to three conditions (EtOH, MgCl2, and controls) and video recorded for 15min (5min before, 5min during, and 5min after immersion in the anesthetic solutions). In each group, the heart rate, respiratory rate, buoyancy, chromatophore activity, and tentacles/arms responses were assessed to evaluate the embryos' vitality and responsiveness to stimulation. Both substances provoked a decrease in heart and respiratory rates and inhibited buoyancy, chromatophores, and tentacles/arms responses; no adverse effects were observed. EtOH had a faster onset of action and faster recovery than MgCl2, being potentially more adequate as an anesthetic for shorter procedures. Even though MgCl2 caused a longer muscle relaxation, the reversibility was not confirmed for the 1.8% concentration; however, lower concentrations triggered similar results as the ones obtained with the highest EtOH concentrations. We have shown that the late developmental stages of Loligo vulgaris embryos could represent a good model to evaluate anesthetics for cephalopods since they can display similar reactions to anesthetics as adults animals do.

Substituting Fat with Olive Oil, Mash Potato, or a Gelatin Matrix in Low-Salt-Content Dry-Fermented Sausages.

It was investigated whether physicochemical properties and consumer perception of dry-fermented sausages were affected by the partial replacement of fat and salt by other compounds. A control batch and nine experimental batches, following 3 × 3 factorial design, were manufactured. The NaCl was replaced with of calcium lactate, magnesium chloride, or a blend 85% NaCl (sodium chloride) and 15% KCl (potassium chloride). The fat was partially substituted by olive oil, potato puree, or commercial gelatin. The pH, dry matter, fat content, free fatty acid content, peroxide index, microbial analysis, and tasting, were measured. Both fat type and slat type were affected to measured variables. In terms of moisture, gelatin would be the most recommendable substitute for fat, whereas KCL would be the better substitute for salt. The three oil batches and the potato-magnesium batches presented lower fat content than the control batch. Both the free fatty acid content and the peroxide values increased over the ripening time. At the end of the ripening, the three oil batches presented the highest values for free fatty acids, but there were no differences among the batches of peroxide index. Regarding bacterial counts, the potato-KCL batch was the most like the control batch. In visual appraisal, none of the scores of the measured variables were affected by the batch. Nevertheless, the batch of oil-magnesium would be purchased less than expected. The tasting quality was affected only by the salt type, but all of the batches were different from the control. Neither the gender (p > 0.05) nor the age (p > 0.05) of the respondents affected the taste scores, visual appraisal, or purchase intent. Results shows that the partial substitution of fat and salt in dry-fermented sausages is possible, even in greater percentages than those stated in the literature, without a detriment of sensory properties. Nevertheless, further experiments would be necessary to adjust the formulation, as well as to explore other possibilities.

Activation energy dependence on doping concentration in PVA-MgCl2 composites

Solid polymer electrolytes are fast replacing the liquid ones because of their numerous advantages such as high energy density, long cycling life, fast charging, low leakage currents and easy fabrication in a variety of shapes. Although most of the reports are based on Li-ion batteries, focus is slowly shifting to develop electrolytes with Group II elements such as Magnesium and Calcium because of their easy availability and moderate ionic activity.In this work, we have complexed polymer polyvinyl alcohol with Magnesium Chloride (MgCl2·6H2O) at different weight percentages. DC conductivity studies were conducted using a two probe setup. It is seen that the activation energy of the system depends on ionic conductivity which in turn depend on the percolating interfacial effect, i.e. anions adsorb on the surface of fillers (and then break up the ion pair and lead to increased interfacial ionic conductivity.This increased conductivity is partly due to the doping and partly due to midgap energy levels developing due to formation of polarons and bipolarons in the composite gel polymer electrolyte .

Effect of cation type on corrosion of steel treated by DNA corrosion inhibitor in simulated concrete pore solution

The purpose of this study is to evaluate the influence of cation types on the rust resistance performance of new nucleic acid corrosion inhibitors in simulated concrete pore solution. Four common chlorinated ice salts (sodium chloride (NaCl), potassium choride (KCl), calcium chloride (CaCl2) and magnesium chloride (MgCl2)) were selected to study the corrosion behaviour of chloride ions by linear polarisation resistance method, electrochemical impedance spectroscopy and X-ray photoelectron spectroscopy. The results show that the cationic type will affect the thickness of the passivated film on the steel surface and the compactness of the passivated film formed by iron oxide and nucleic acid rust inhibitor. The type of cations affects the critical chloride concentration of nucleic acid inhibitor, following Na+ ≈ K+ > Ca2+ > Mg2+.

Rechargeable Magnesium Ion Batteries Based on Nanostructured Tungsten Disulfide Cathodes

Finding effective cathode materials is currently one of the key barriers to the development of magnesium batteries, which offer enticing prospects of larger capacities alongside improved safety relative to Li-ion batteries. Here, we report the hydrothermal synthesis of several types of WS2 nanostructures and their performance as magnesium battery cathodes. The morphology of WS2 materials was controlled through the use of sodium oxalate as a complexing agent and different templating agents, including polyethylene glycol (PEG), polyvinylpyrrolidone (PVP), and hexadecyltrimethyl ammonium bromide (CTAB). A high capacity of 142.7 mAh/g was achieved after 100 cycles at a high current density of 500 mA/g for cathodes based on a nanostructured flower-like WS2. A solution consisting of magnesium (II) bis(trifluoromethanesulfonyl)imide (MgTFSI2) and magnesium (II) chloride (MgCl2) in dimethoxyethane (DME) was used as an effective electrolyte, which contributes to favorable Mg2+ mobility. Weaker ionic bonds and van der Waals forces of WS2 compared with other transition metal oxides/sulfides lay the foundation for fast discharge/charge rate. The enhanced surface area of the nanostructured materials plays a key role in enhancing both the capacity and discharge/charge rate.

Effect of magnesium salt contamination on the microstructures and properties of metakaolinite-based geopolymer: the role of MgCl2 and MgSO4

Ion contamination considerably influences the properties of geopolymers. This study investigated the effects of magnesium chloride (MgCl2) and magnesium sulfate (MgSO4) concentrations on the microstructure and properties of metakaolinite-based geopolymers with Si/Al ratios of 1.3 (adding NaOH) and 1.6 (adding NaOH and Na2SiO3). The chemical structures and compositions of as-obtained geopolymers formed through the alkali activation of kaolinite were characterized through X-ray diffraction, Fourier-transform infrared spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy, while the microstructure was characterised via scanning electron microscopy and mercury intrusion porosimetry.The salt-free geopolymer with a Si/Al ratio of 1.3 exhibited a loose microstructure and hence poor 28-day compressive strength (9.4 MPa). The addition of magnesium salt to the geopolymer did not considerably influence its microstructure and mechanical properties. Comparatively, the geopolymer with a Si/Al ratio of 1.6 exhibited a compact microstructure and high 28-day compressive strength (43.0 MPa). The geopolymer compressive strength gradually decreased with increasing salt concentration. MgCl2 addition induced halite formation, increased pore diameter and pore volume, and reduced Si incorporated into the geopolymer matrix. In contrast, MgSO4 addition resulted in relatively less change in the pore diameter and pore volume and based on NMR result, more Si was incorporated into the geopolymer matrix. Thus, MgCl2 was more detrimental to the mechanical properties of the kaolinite-based geopolymers than MgSO4.Overall, the results indicate that salt contamination considerably affects the chemical compositions, microstructural characteristics, and compressive strength of metakaolinite-based geopolymers at high Si/Al ratio (adding NaOH and Na2SiO3) and those chlorine ions are more detrimental to the properties of metakaolinite-based geopolymer than sulfate ions.

Prophylactic Administration of Magnesium Oxide Prevents Dextran Sulfate Sodium-Induced Colonic Injury in Mice.

We previously demonstrated that per os administration and ad libitum ingestion of a magnesium chloride (MgCl2) solution had a prophylactic effect on dextran sulfate sodium (DSS)-induced colitis in mice, magnesium being considered to play a role in this preferable action. Magnesium oxide (MgO) is a commercially available magnesium formulation, but whether or not it prevents development of colitis is unknown. In this study, we investigated the effect of MgO administration on development of colitis in DSS-treated male C57BL/6J mice. Experimental colitis was induced by ad libitum ingestion of 1% (w/v) DSS, and the colitis severity was evaluated by disease activity index (DAI) scores, histological assessment and colonic expression of inflammatory cytokines. A 1 mg/mL MgO solution was administered to mice through ad libitum ingestion from a day before DSS treatment to the end of the experimental period of 12 d. In addition, the effects of DSS, MgO and their combination on the gut microbiota were investigated by 16S ribosomal RNA metagenome analysis. DSS-induced elevation of DAI scores was partially but significantly decreased by MgO administration, while MgO administration had no apparent effect on the shortened colonic length, elevated mRNA expression of colonic interleukin-1β and tumor necrosis factor-α, increased accumulation of colonic mast cells, or altered features of the gut microbiota in DSS-treated mice. Overall, we demonstrated that MgO had a prophylactic effect on the development of colitis in DSS-treated mice by preventing histological colonic damage, but not colonic inflammation or alteration of the gut microbiota.