Magnesium Hydroxide Suspensions Research Articles

DESULFURIZATION OF FLUE GASES OF THERMAL POWER PLANTS WITH OBTAINING POTASSIUM-MAGNESIUM FERTILIZER (KALIMAGNESIA)

A new method of flue gas desulfurization with the production of a valuable is proposed. The essence of the method is to pass flue gases through a scrubber (Venturi) filled with magnesium hydroxide suspension. At the same time, SO2 of the flue gases will react with magnesium hydroxide according with the formation of magnesium sulfite. Crystals of magnesium sulfite are able to interact with new portions of SO2 and turn into hydrosulfite. As a result of such "washing" of flue gases, a suspension of sparingly soluble salt MgSO3∙6H2O in a 12-15% solution of MgSO4 is obtained. Magnesium hexahydrate will precipitate as large crystals and be separated in a hydrocyclone. Separated crystals of magnesium sulfite will be oxidized under the influence of air oxygen to magnesium sulfate.

Comparing Golqand (Persian Medicine Product) with Magnesium Hydroxide in Adult Constipation: A Randomized Clinical Trial

Chronic constipation is a highly prevalent digestive problem in the community, which would decrease the quality of life of individuals. There is not any conclusive drug of choice for constipation. Golqand (combined Rosa × damascena Herrm. and honey) has been introduced as an effective safe laxative in Persian medicine (PM). This study aimed to investigate the effects of Golqand in comparison with Magnesium hydroxide suspension (MOM) in chronic constipation. In this clinical trial, fifty-six patients with chronic constipation were randomly assigned to the study groups of Golqand or MOM. Patients received Golqand (20 g daily) or MOM (40 mL daily) for 2 weeks. Patients took the drug twice a day, MOM group used it in the morning (20 mL) and at night before going to bed (20 mL). The Golqand group used it 10 g before lunch and 10 g before dinner, dissolved it in lukewarm water and swallowed. Then, they were followed for the second two weeks without any medication. The primary outcome was frequency of defecation. Patients were evaluated before the study and two weeks and four weeks after the beginning study. Estimated marginal mean frequency of defecation in the MOM group in the first two weeks was significantly higher than the Golqnd group (P < 0.05). There was no significant difference among the groups in the third week when treatment was discontinued (P = 0.155) but in the fourth week, the Golqand group had more count of defecation than the MOM group (P = 0.001). There was no significant difference between the two study groups in terms of treatment satisfaction and drug side effects (P > 0.05). Golqand medication can be used in the treatment of constipation with very few drug side effects and a more lasting effect than MOM drug.

Гибридная система «слоистый силикат магния – хлорин е6 13(1), 17(3)-N,N'-(2-гидроксиэтил)диамид 15(2)-метиловый эфир»

Hectorite type layered magnesium silicate have been synthesized by heat treatment of reaction mixture freshly prepared magnesium hydroxide suspension, silica sol, lithium fluoride solution. The starting Mg(OH)2 : SiO2 : LiF molar ratio was 1 : 1.51 : 0.25. Hybrid systems have been synthesized by heat treatment of synthetic layered magnesium silicate in water-ethanol solution of chlorin е6 13 (1), 17(3)-N,N'-(2-hydroxyethyl) diamide 15(2)-methyl ester. The systems contain of 0.85∙10-6 and 1.4∙10-6mol of the organic component per 1 g of layered magnesium silicate. The introduction of the chlorin e6 derivative into hectorite type layered magnesium silicate sol promotes the aggregation processes and growth particles of the hybrid samples (250±5 nm), as compared with the particles of magnesium silicate (133±1 nm). X-ray phase analysis, UV-Vis spectroscopy and laser Doppler electrophoresis studies have been allowed to establish that non-aggregated molecules of the chlorin e6 derivative are located on the surface of magnesium silicate particles.UV-Vis spectroscopy study showed protonation of nitrogen atoms of the chlorine macrocycle of the chlorin e6 derivative molecules (Soret band 405-406 nm; Q-band 642-643 nm) by hydroxyl groups of the layered magnesium silicate. Chlorin е6 13 (1), 17(3)-N,N'-(2-hydroxyethyl) diamide 15(2)-methyl ester sorption on the surface of magnesium silicate particles occurs due to electrostatic interaction between protonated chlorine e6 derivative molecules and ionized hydroxyl groups of the magnesium silicate.

Synthesizing Alkaline Earth Metal Hydroxides Nanoparticles through an Innovative, Single-Step and Eco-Friendly Method

The objective of this paper is to introduce a patented and eco-friendly method to synthesize aqueous suspension of all types of alkaline-earth metal hydroxides nanoparticles (NPs). This method is based on an ion exchange process; the exchange takes place at ambient temperature/pressure, starts from cheap or renewable reagents and, in one single step, results in the creation of the crystalline desired nanoparticles in only a few minutes. In terms of structural and morphological features, the synthesized nanoparticles are characterized by means of XRD-Rietveld refinement, FTIR, and TEM. In particular, we obtained pure and crystalline magnesium and calcium hydroxide suspensions, showing the typical brucite crystal structure with a hexagonal lamellar morphology and dimensions generally <100 nm. With respect to the strontium and barium hydroxide suspensions, we observed different kinds of hydroxides (either anhydrous and hydrate forms), characterized by orthorhombic or monoclinic crystal lattices with rod-like nanostructured morphologies. Despite the different morphologies, all synthesized nanoparticles appear constituted by a superimposition of primary nanoparticles, of dimensions ranging from a few to 15 nm, correlated to the increase in the atomic number of the alkaline earth metal.

Quartz crystal microbalance as a device to measure the yield stress of colloidal suspensions

The application of quartz crystal microbalance (QCM) as a device to measure the rheology of colloidal suspensions has been studied. Using a commercial dip-probe QCM, the yield stress of magnesium hydroxide suspensions has been correlated to the resonance properties of a 5 MHz AT-cut quartz sensor. A stable resonance baseline was first established in air before submerging the sensor into the colloidal suspension. The response of the sensor resistance was shown to correlate to changes in the suspension yield stress, while the frequency response was found to result from more complex contact mechanics and suspension viscoelasticity contributions. Since the QCM is a relatively simple technique with no mechanically moving parts, this approach offers the potential for rapid in situ rheology assessment.

Improvement in Salt-Tolerance of Aqueous Magnesium Hydroxide Suspensions by Comb-Like Polyelectrolyte

The rheological behavior and stability of aqueous magnesium hydroxide (Mg(OH)2) suspensions were studied in the presence of comb-like polyelectrolyte, namely, sodium salts of poly(acrylic acid)-poly(ethylene oxide) (NaPAA–PEO) at high ionic strength. Rheological, sedimentation, and zeta potential measurements were conducted on Mg(OH)2 suspensions to assess the dispersing ability of NaPAA–PEO. The adsorption behavior of NaPAA–PEO on the surfaces of Mg(OH)2 particles was investigated by the adsorption isotherm measurements. The interparticle interactions were calculated by using the Hamaker 2 program to evaluate the effect of NaPAA–PEO dosage on the stability of suspensions. The results indicated that NaPAA–PEO, which is insensitive to ionic strength variation, could improve the salt-tolerance of Mg(OH)2 suspensions and provide effective electrosteric stabilization, thus facilitating the production process and application of Mg(OH)2 suspensions over broad range of ionic strength.

The rheological behavior and stability of Mg(OH)2 aqueous suspensions in the presence of sodium polyacrylate

The magnesium hydroxide (Mg(OH)2) aqueous suspensions were prepared over a wide range of solid loading using sodium polyacrylate (NaPA) as the dispersant. The effects of solid loading, polyelectrolyte concentration, shear rate, temperature and ionic strength on the rheological behavior and stability of Mg(OH)2 aqueous suspensions have been investigated by means of viscosity and sedimentation measurements. The results showed that the apparent viscosity of the concentrated magnesium hydroxide suspensions decreased pronouncedly as the dispersant dosage was increased and reached a minimum as the dispersant concentration exceeded 0.6wt% (based on the dry powder weight). The fitting of shear stress-shear rate dependence curves with several models showed that the suspensions appeared to shift toward a Bingham-plastic flow from the shear thinning flow behavior as the NaPA dosage increased. This suggests that NaPA displays outstanding dispersing and stabilizing effects in the studied system, further evidenced by the sedimentation measurement. In addition, the apparent viscosity was also found to increase with the solid loading in the systems of aqueous Mg(OH)2 suspensions with 0.6wt% NaPA. A maximum solid loading (ϕm) at which the particulate suspensions changed from a fluid-like form into a solid-like form was determined from the ηr−ϕ relationship, using the Krieger-Dougherty model, to be 45vol% and 54vol% at shear rate of 10s−1 and 100s−1, respectively. Ionic strength and temperature also influenced the rheological behavior and stability significantly, such that lower temperature or higher ionic strength could increase the apparent viscosity. Lastly, a possible stabilization mechanism at various NaPA concentrations was discussed based on the adsorption behavior and adsorbed layer conformation of the dispersant on the particle surface.

The Effect of Electrolyte Concentration and Polymer Content on the Rheological Behavior of Magnesium Hydroxide Suspension

The Effect of Electrolyte Concentration and Polymer Content on the Rheological Behavior of Magnesium Hydroxide Suspension

The Effect of Electrolyte Concentration and Polymer Content on the Rheological Behavior of Magnesium Hydroxide Suspension

Aims: Magnesium hydroxide (Mg (OH) 2) is an alkaline compound that is used as an anti-acid and laxative agent. The objective of the study was to find the effect of electrolyte concentration and polymers on the rheological behavior of Mg (OH) 2 suspension.

Aluminum Hydroxide Plus Magnesium Hydroxide Plus Oxetacaine Suspension Versus Aluminum Hydroxide Plus Magnesium Hydroxide Suspension for Acute Radiation-Induced Esophagitis in Cancer Treatment: Final Results of a Double-Blind Randomized Trial

Aluminum Hydroxide Plus Magnesium Hydroxide Plus Oxetacaine Suspension Versus Aluminum Hydroxide Plus Magnesium Hydroxide Suspension for Acute Radiation-Induced Esophagitis in Cancer Treatment: Final Results of a Double-Blind Randomized Trial

Radiation-induced esophagitis: A double-blind randomized clinical trial of aluminum hydroxide plus magnesium hydroxide plus oxetacaine suspension versus aluminum hydroxide plus magnesium hydroxide suspension

9100 Background: To assess whether oral administered oxetacaine-containing suspension is effective in treating acute radiation- induced esophagitis in cancer patients. Methods: A double-blind, prospective-randomized clinical trial was conducted across 20 radiotherapy institutions in Germany. Patients [pts.] with head and neck or thoracic cancer without dysphagia/odynophagia received definitive or postoperative radiotherapy [RT] with or without chemotherapy including at least 5 cm of the esophagus in the high dose volume. Pts. were randomized to receive oral aluminum hydroxide plus magnesium hydroxide plus oxetacaine (Tepilta [T]) suspension or aluminum hydroxide plus magnesium hydroxide suspension without oxetacaine (Magaldrat [M]) as first-line treatment for acute radiation-induced esophagitis. Primary endpoint was the interval between begin of RT and failure of first-line treatment of esophagitis defined as need for additional systemic analgesics. Data on pts.’ symptoms were collected during and for at least 2 weeks after treatment. Results: A total of 158 pts. were randomized, of whom 103 had take at least one dose of the study medication for acute esophagitis = grade 2 (CTC). Of the 105 pts., 51 were randomized to receive T and 52 M. The cumulative incidence of acute esophagitis = grade 2 (CTC) was 25% for the T and 22% for the M arm. Kaplan-Meier analysis showed a statistically significant difference between the two groups regarding the need for systemic analgesics under consideration of the intake time in favor of T (p = 0.032). No statistically significant difference was found between the two groups regarding the secondary endpoints need respective delay of additional parenteral nutrition (p = 0.28 respective p = 0.12), and pts.`s and investigator`s estimation of global effectivity of the study medication (0.08 and 0.12). Conclusions: This trial demonstrated a statistically significant delay of the intake time for systemic analgesics in pts. randomized to receive oral aluminum hydroxide plus magnesium hydroxide plus oxetacaine suspension. No significant financial relationships to disclose.

Formation of dynamic membranes for oily water separation by crossflow filtration

This paper presents the results of a study of dynamic membranes for oily water separation. The formation of the dynamic membranes and their performance in oily water separation were investigated. The results showed that a magnesium hydroxide suspension, made by a simple reaction process with salt and sodium hydroxide, was a suitable material for dynamic membrane formation on the ceramic support. A dynamic membrane with a uniform and compact structure was formed using the crossflow filtration technique. The formed dynamic membranes were reproducible and gave good performance in separating oil from water using a model oil emulsion in an alkaline environment. The oil retention was more than 98% and the permeate flux was more than 100 L m −2 h −1 at 100 kPa in a batch concentration test.

Crossflow microfiltration of magnesium hydroxide suspensions: determination of critical fluxes, measurement and modelling of fouling.

Abstract Crossflow microfiltration experiments with two magnesium hydroxide suspensions (non-Newtonian, broad particle size distribution) were performed at constant permeate flow rate and under turbulent flow conditions. Critical fluxes (strong form) were measured for different crossflow velocities and concentrations. Fouling experiments were also undertaken and the influence of the crossflow velocity and the permeate flow rate on the cake resistance and specific resistance was studied. It was found that the two suspensions made from the same material, with similar measured particle size distribution and zeta potential but with different rheological and settling properties exhibit very different filtration behaviours. Based on the friction force model [1] , a shear stress model which uses the critical flux measurements has been developed to predict the deposit thickness. At the steady state, a good agreement between experiment and theory was found for cakes formed under turbulent flow conditions.

Studies on the lead-catalyzed synthesis of aldopentoses.

The object of this work was to find an efficient means of synthesizing ribose in a manner that could be considered prebiotic. The starting point for synthesis was an aqueous solution of formaldehyde. Heretofore the most frequently used catalyst for this purpose has been calcium hydroxide. Unfortunately this system produces a wide array of products in addition to ribose which constitutes 1% or less of the final product. Attempts were made to find more mild conditions under which the formaldehyde could be reacted. Magnesium hydroxide suspensions were used for this purpose. Formaldehyde does not yield any sugars when incubated in magnesium hydroxide suspensions alone. However, if the magnesium hydroxide suspension was supplemented with doubly charged lead salts and catalytic amounts of any intermediate in the prebiotic pentose pathway, aldopentoses accounted for 30 per cent or more of the final product. The presence of lead in the incubation mixture also accelerated a number of other reactions including the interconversion of the four common aldopentoses, ribose, arabinose, lyxose and xylose.

An anomalous electrorheological behavior of magnesium hydroxide suspensions in silicone oil

In contrast to the usual electrorheological behavior manifesting in an increase in viscosity of suspensions of various materials in electrical field, a negative electrorheological effect, i.e., a decrease in viscosity of suspensions of magnesium hydroxide particles in silicone oil was observed.

高齢者に適した医薬品剤型の検討 水酸化アルミニウムゲル・水酸化マグネシウム懸濁配合剤の薬用量調査

A suspension of aluminum hydroxide and magnesium hydroxide is frequently prescribed to treat gastric ulcer and gastritis. The proper dosage was investigated using the 1126 prescriptions from eight general hospitals and two university hospitals.The number of prescription increased along with the patient age. The ratio of prescription in the population aging over 65 years reached 41.1%. The patients were instructed to take the prescription 3 or 4 times every day; between meals or before meals and at bed time. The dosage per time was 5 ml for the ratio of 1.7% in all prescription, 10 ml at 75.7%, 15 ml at 8.1%, and 20 ml at 11.7%.The single-dose package containing 10 ml of the aluminum hydroxide and magnesium hydroxide suspension is considered advisable as a suitable dosage form for elderly patients.

Heterocoagulation in Magnesium Hydroxide and Aluminum Hydroxycarbonate Suspensions

Magnesium hydroxide and aluminum hydroxycarbonate interact in mixed suspensions resulting in the formation of agglomerates containing both types of particles. Direct visual evidence of the phenomenon was gained from scanning electron microscopy studies carried out on a model of the system employing a highly crystalline magnesium hydroxide of large particle size and from transmission electron microscopy of mixed colloidal suspensions. Doppler electrophoretic light scattering measurements on mixed colloid systems supported the findings as two distinct electrokinetic populations of particles were initially present which corresponded to the zeta potentials of magnesium hydroxide and aluminum hydroxycarbonate. The two populations were observed to transform over time into a single population having an intermediate zeta potential. Solubilization of both types of particles apparently takes place, leading to changes in bulk pH and ionic strength of the mixtures.

A Comparison of the Coefficients in the Richardson and Zaki's and Steinour's Equations Relating to the Behavior of Concentrated Suspensions

Abstract Steinour and Richardson and Zaki proposed relationships to explain the hindered settling phenomena from their independent experiments about 10 years apart. An attempt has been made to compare the coefficients and derive a relationship between Steinour's parameter A and Richardson and Zaki's parameter n. It is possible to express this relationship in the form of an equation involving parameters for which values can be assigned. Theoretically, this derived relationship should be applicable to any sedimenting suspension which obeys both Steinour's and Richardson and Zaki's equations. This derived expression has been evaluated for various experimentally determined values of A and n. The experimental systems which have been tested include calcium carbonate suspensions in water, sucrose-water, and glycerin-water solutions, and ethyl alcohol and magnesium hydroxide suspensions in glycerin-water, sucrose-water and sorbitol-water solutions. The calculated values have been shown to agree well with experime...

The Coprecipitation of Magnesium Iron (III) Hydroxide Powders from Aqueous Solution: Precipitate Compositions and Coprecipitation and Ageing Mechanisms

AbstractSeries of magnesium iron(111) hydroxides were coprecipitated at ambient temperature from different mixed metal cation solutions, at CM tot = 0.1 M and Mg/Fe2 ratios from 4 to 1/4, with sodium hydroxide solution. The relevant single precipitations and the coprecipitations were monitored by potentiometric (pH) titration and the final coprecipitate compositions were examined by chemical analysis, infra‐red spectrophotometry and thermal analysis.The coprecipitates onto aged α‐FeOOH were simple mixtures of α‐FeOOH and Mg(OH)2. The main coprecipitates were either «molecular inclusion mixtures» of microcrystalline α‐FeOOH with excess Mg(OH)2 or similar mixtures of Mg(OH)2 with excess α‐FeOOH and some ten‐twenty percent (relative to the Mg content) of magnesium hydroxo‐ferrate(III) hydrate Mg[Fe(OH)4]2 · h H2O. The coprecipitates aged in alkaline magnesium hydroxide suspension at 20 °C and 40 °C were mixtures of Mg(OH)2, α‐FeOOH and forty to ninety percent (relative to the Mg content) of Mg[Fe(OH)4]2 · h H2O.The related α‐FeOOHNaOH and α‐FeOOHMg(OH)2 equilibria and the different coprecipitation mechanisms are discussed.

The Coprecipitation of Magnesium Titanyl Hydroxide Powders from Aqueous Solution: Precipitate Compositions and Coprecipitation and Ageing Mechanisms

AbstractSeries of magnesium titanyl hydroxides were coprecipitated at ambient temperature, from different mixed metal cation solutions at CM tot = 0.1 M and Mg/TiO ratios from 2 to 1/2), with sodium hydroxide solution. The relevant single precipitations and the coprecipitations were monitored by potentiometric pH titration and the final coprecipitate compositions were examined by chemical analysis, infra‐red spectrophotometry and thermal analysis.The main coprecipitates were «intramicellar mixtures» of microcrystalline titanyl hydroxide with excess magnesium hydroxide or of magnesium hydroxide with excess titanyl hydroxide. The coprecipitates aged in alkaline magnesium hydroxide suspension were mixtures of titanyl hydroxide, magnesium hydroxide and from fifty to ninety percent (relative to the original/magnesium content) of magnesium hydroxotitanate hydrates Mg[TiO(OH)4] · h H2O, Mg[TiO2(OH)2] · h H2O and Mg[Ti2O2(OH)6] · h H2O.