Magnesium Peroxide Research Articles

Control of BTEX Migration Using a Biologically Enhanced Permeable Barrier

AbstractA permeable barrier system. consisting of a line of closely spaced wclls. was installed perpendicular to ground water flow to control the migration of a dissolved hydrocarhon plume. The wells were charged wiih concrete briquets that release oxygen and nitrate at a controlled rate. enhancing aerobic bio‐degradation in the downgradient aquifer.Laboratory batch reactor experiments were conducted to identify concrete mixtures that slowly released oxygcn over an extended time period. Concretes prepared with urea hydrogen peroxide were unsatisfactory, while concretes prepared with calcium peroxide and a proprietary formalation of magnesium peroxide (ORC®) gradually released oxygen at a steadily declining rate. The 21 percent MgO2 conerete cylinders and briquets released oxygen at measurable rates for up to 300 days, while the 14 percent CaO2 briquets were exhausted by 100 days.A full‐scale permeable barrier system using ORC was constructed at a gasoline‐spill site. During the first 242 days of operation. total BTFX decreased from 17 to 3.4 mg/L. and dissolved oxygen increased from 0.4 to 1.8 mg/L. during transport through the barrier. Over time, BTEX treatment efficiencies declined. indicating the barrier system had becomc less effective in releasing oxygen and nutrients to the highly contaminated portion of the aquifer. Point dilution tests and sediment analyses performed at the conclusion of the project indicated that ihc aquifer in the vicinity of the remediation wells had been clogged by precipitation with iron minerals. This clogging is believed to result from high pH from the concrete and oxygen released by ihc ORC. Oxygen‐releasing permeable barriers and other aerobic bioremediation processes should be used with caution in aquifers with high levels of dissolved iron.

Enhanced intrinsic bioremediation of hydrocarbons using an oxygen‐releasing compound

AbstractAn “oxygen barrier” was formed by depositing an oxygen‐releasing compound in a series of wells that were placed perpendicular to the direction of groundwater flow at a site in Belen, New Mexico. The objective was to enhance the intrinsic bioremediation of dissolved phase BTEX contamination in the aquifer and to quantify the results. The oxygen was supplied by a controlled release formulation of magnesium peroxide called Oxygen Release Compound (ORC®), a virtually insoluble powder that is packaged in polyester filter socks. The areal distributions of the initial concentrations of dissolved oxygen and BTEX were measured and compared to the concentration changes at various times in the first 93 days of system operation. The concomitant reduction in BTEX can be seen in a series of contour plots. In 93 days, dissolved oxygen had dispersed at least 20‐feet downgradient from the ORC source wells based on the pattern of decreasing BTEX concentrations.

Sol-Gel Preparation and Characterization of Magnesium Peroxide, Magnesium Hydroxide Methoxide, and Randomly and (111) Oriented MgO Thin Films

Sol-Gel Preparation and Characterization of Magnesium Peroxide, Magnesium Hydroxide Methoxide, and Randomly and (111) Oriented MgO Thin Films

XPS characterization of ultra-thin MgO films on a Mo(100) surface

The oxidation of ultra-thin Mg films supported on a Mo(100) surface has been studied using X-ray photoelectron spectroscopy (XPS) in the 90–1300 K sample temperature range. Upon adsorption of oxygen onto Mg thin films or deposition of Mg in the presence of oxygen, a Mg(2p) XPS feature at ~ 50.5–50.8 eV is observed. The binding energy of this peak is higher than that of metallic Mg(2p) (at 49.6 eV) and is assigned to oxidized magnesium. The associated O(1s) XPS spectra exhibit two peaks which can be attributed to a dioxygen species concluded to be magnesium peroxide and the lattice oxygen in MgO. Upon annealing the peroxide containing film to ~ 700 K, the magnesium peroxide is reduced to MgO through the loss of oxygen and metallic magnesium existing within the film is subsequently oxidized to MgO. Mg deposition in an oxygen background (~ 10−6 Torr) onto the Mo(100) surface at 300 K produces essentially stoichiometric MgO films.

Inactivation of bacteria by solids coated with magnesium peroxide

Abstract Heating diatomaceous earth or sand that has been soaked with a solution of magnesium chloride results in coating of the materials with magnesium oxide. The addition of hydrogen peroxide converts this coating to magnesium peroxide. The magnesium peroxide coating on sand or diatomaceous earth is relatively stable during storage. Greater than 50% of the oxidizing power remained after 6 months storage at room temperature. The addition of diatomaceous earth or sand coated with magnesium peroxide to aqueous solutions led to release of hydrogen peroxide into the solution, reduced the number of bacteria, and prevented bacterial growth as compared with controls. Filters made with modified and untreated diatomaceous earth removed bacteria from water equally well. However, bacteria survived or grew on filters made with untreated materials, but were greatly reduced in numbers on filters made with modified diatomaceous earth.

Catalytic Decomposition Kinetics of Aqueous Hydrogen Peroxide and Solid Magnesium Peroxide By Birnessite

AbstractPeroxides are used as O2‐generating agents. The decomposition of H2O2 (aq) or MgO2(s) in the presence of synthetic birnessite [δ‐MnO2(s)] as a catalyst was observed by measuring the volume of O2(g) given off. The experimental data fit a first‐order kinetic law and the mechanism proposed by Habes and Weiss can explain the experimental results obtained for the decomposition of H2O2(aq). The applicability of the proposed mechanism involving H2O2(aq) was based on the following: (i) the activation energy was relatively high (82 ± 3 kJ mol−1); (ii) the rate constant (k) was pH dependent, indicating that H+ and OH‐ ions were formed in the process; (iii) a linear relationship (and not logarithmic) between k and the ionic strength indicated a reaction between an ion and a neutral molecule; and (iv) using birnessite with different fractional coverages of Co indicated that the reaction was heterogeneously catalyzed by Mnz+1/Mnz active centers. Regarding MgO2(s) decomposition, the experimental data obtained at pH 7.6 followed a rate law derived from a shrinking‐core model for fixed‐size particles. The rate of the reaction was controlled by diffusion through the Mg(OH)2(s) product layer rather than by chemical reaction at the core surface. Compared with ionic peroxides, MgO2(s) could be a potential O2‐generating agent for generating O2(g) during a relatively long period of time.

Adsorption of Viruses by Diatomaceous Earth Coated with Metallic Oxides and Metallic Peroxides

Diatomaceous earth coated with oxides of aluminium, calcium, iron, magnesium, or manganese were not found to be useful for recovering viruses from water. The oxide coatings were not stable in water or only adsorbed viruses in small volumes of water. Further modification of coatings of magnesium oxide to make magnesium peroxide produced a modified diatomaceous earth that efficiently adsorbed viruses in water. Filters containing 3.5 g of diatomaceous earth adsorbed an average of greater than 90% of MS2, polio 1, coxsackie B5, and echo 5 in tapwater at approximately pH 8.5, even after 100 liters of tapwater had passed through the filters. From 15 to 40% of MS2 or enteroviruses could be recovered from tapwater using filters containing diatomaceous earth coated with magnesium peroxide.

Stabilization of iron-catalysed hydrogen peroxide decomposition by magnesium

Catalytic decomposition of alkaline hydrogen peroxide by iron can be retarded by introduction of magnesium ions. This effect has been studied to evaluate the possibility of stabilization via formation of an iron–magnesium complex species. Under alkaline conditions, magnesium reacts with initial hydrolysis products of Fe3+ to produce a colourless complex species, in which the metal centres are probably linked through oxy or hydroxy bridges. This species is produced when the Mg:Fe molar ratio exceeds 6:1, and this ratio is also significant when magnesium is introduced during peroxide decomposition experiments. The evidence suggests that complex formation is an important factor in producing stabilization, and cannot be disregarded in favour of an alternative explanation where superoxide radicals combine with Mg2+ to produce magnesium dioxide. Keywords: hydrogen peroxide, kinetics, iron, magnesium, stabilization.

Microporous filters with oxidizing power for iron and manganese removal from water

Abstract This report describes the development of a microporous filter carrying oxidizing power to convert the ionic species in water from soluble form, such as Fe+Z and Mn+2, to insoluble form, thus allowing for their continuous removal in one step. The filters were constructed with a celluloslc fiber network for immobilizing adsorbent particles carrying oxidizing power. The porosity of the filters was controlled by selecting the proper size of the binding fibers and the adsorbent. A number of substances were incorporated into the filter matrix and tested for their ability to remove soluble iron from water. Magnesium peroxide was found to be the most effective and was capable of removing significant quantities of iron from water at high flow rates. Removal is believed to take place by a combination of ferric ion adsorption, oxidation to insoluble ferrous hydroxide and filtration. Construction of filter cartridges demonstrated the effectiveness of the material for home water purification.

Microbial removal and inactivation from water by filters containing magnesium peroxide

Abstract Microporous filters containing MgO2 were shown to be effective in the removal and inactivation of bacteria and viruses from tapwater. Pseudomonas aeruginosa, P. cepacia and Escherichia coli collected by the filters were found to rapidly decrease in numbers to undetectable levels within 24 hours. In contrast, the same bacteria collected on identical filters not containing MgO2, either rapidly increased in numbers or their numbers remained unchanged. Poliovirus type 1, Echovirus type 1, Reovirus type 3 and Rotavirus SA‐11 were found to readily adsorb to the filters. The numbers of viruses which could be recovered from the MgO2 containing filters decreased rapidly with time as compared to control filters. No significant inactivation of bacteria or viruses occurred in tapwater passed through the filters, strongly suggesting that the microorganisms were being inactivated while adsorbed to the filters and not by substances released by the filters into the water. The filters remained effective even afte...

Protecting groundwater from viral contamination by soil modification

Abstract During land application of domestic wastewater, pathogenic enteric viruses may gain entrance into groundwater. Soil modification to enhance virus removal as a method of groundwater protection is described. Inorganic substances were added to a column of sandy loam to assess their ability to enhance the removal of coliphage MS‐2 and poliovirus from tapwater and secondarily treated sewage. Aluminum metal, magnesium oxide and magnesium peroxide when added to the soil were found to significantly enhance virus removal above that observed in control columns. Powdered metallic aluminum caused an average decrease of greater than five logs in virus concentration, while control columns containing no aluminum showed only a two log decrease. Significant reduction in the number of viruses continued in test columns during five weeks of intermittent flooding. The efficiency of virus removal due to the soil additive declined toward the end of the flooding period. Aluminum metal did not significantly change the pH of the column percolate and was not leached in significant amounts from the soil used in this study when pH 2–3 water was passed through the column for 38 days. Both magnesium oxide and magnesium peroxide, while also effective in virus removal, significantly increased the pH of the column percolate.

Synthesis and properties of analogs of pyridoxal

A method for the synthesis of analogs of pyridoxal-2-norpyridoxal, 6-methyl-2, 4-pyridoxal, and 6-methylpyridoxal—has been worked out. The reaction of 5-ethoxyoxazoles with maleic diesters gave diesters of substituted 3-hydroxycinchomeric acids, which were converted by reduction with lithium aluminum hydride into analogs of pyridoxine. The latter were oxidized with magnesium dioxide to the corresponding analogs of pyridoxal. The oximes of the aldehydes and their Schiff's bases with p-phenetidine have been obtained. Analogs of pyridoxamine have been obtained by the hydrogenation of the oximes. The UV absorption spectra of the compounds and the ratios of the ionic forms in aqueous solutions have been studied.

The formation of magnesium perperoxide Mg(O2)2 in the reaction of magnesium peroxide with ozone

1. The possibility of the formation of a new perperoxide magnesium perperoxide Mg (O2)2 at −85 to −65° in the reaction of ozone, dissolved in Freon-12, with magnesium peroxide, suspended in the same medium, was demonstrated. 2. Preparations were isolated containing ∼60% Mg(O2)2. The individuality of magnesium perperoxide was confirmed by the EPR method. The limit of its thermal stability −35 to −29° was established by the method of differential thermal analysis.

Thermal stability of magnesium peroxide

1. The limits of thermal stability of preparations containing up to 75% MgO2 were determined by the method of differential thermal analysis. 2. It was shown by an interpretation of the thermograms that these preparations release the bulk of the water of the adsorbed mother liquor at 110° and are entirely dehydrated at 260°. In this case there is a partial decomposition of MgO2 with evolution of oxygen and the formation of Mg(OH)2. 3. The mixture of MgO2 and Mg(OH)2 formed decomposes exothermic ally within the range 360–375°, liberating oxygen and forming MgO. The following reactions are responsible for the exothermicity of the effect on the heating curves of magnesium peroxide preparations: MgO2+2H2O→Mg(OH)2+H2O2, H2O2→H2O+1/2 O2.

Syntheses of 9, 9'- Dihalogeno-3, 3'-Dibenzanthronyls

9, 9'-Dihalogeno-3, 3-dibenzanthronyls were prepared as intermediates for the synthesis of diviolanthronyl, a possible high molecular weight dyestuff or a possible electric semiconductor. They were fine yellow crystals and dissolved in concentrated sulfuric acid to give a dark red solution.The 9, 9'-dichloro derivative, mp 4425°C, of 3, 3'-dibenzanthronyl (6) was prepared by the dehydrogenation condensation of 9-chlorobenzanthrone in the presence of magnesium dioxide. 9-Chlorobenzanthrone was obtained by the condensation of α-naphthyl-m-chlorophenylketone in the presence of aluminum chloride or by the partial reduction of 4, 9-dichlorobenzanthrone.Though the 9, 9'-diiodo derivatve, mp 4168°C, of (6) was synthesized in a similar manner from 9-iodobenzanthrone, the reaction was extremely slow and the yield was only 18%. 9-iodo-benzanthrone, mp 1979°C, was prepared in 88% yield by the Griess reaction of 9-aminobenzanthrone in concentrated sulfuric acid.When (6) was treated with an excessive amount of bromine, 9, 9'-dibromo-3, 3'- dibenzanthronyl, mp 4414°C, was obtained in 64% yield. The product was identical with the authentic sample obtained by the dehydrogenation condensation of 9- bromobezanthrone. The 9, 9'-dibromo derivative was also prepared by the bromination of (6) in the presence of catalysts such as aluminum halides.

Stability of the vulcanized cross link in butyl rubber: Theory and application

AbstractIt has been determined analytically that, when a Butyl vulcanizate softens during exposure to high temperature, the disulfide cross links between polymer chains break down to thiol groups. Of all the accelerator types, tellurium derivatives of dithiocarbamic acids impart the greatest inherent resistance to this reversion. Such a mechanism of breakdown, however, suggested the use of oxidizing agents to reform the disulfide cross linkage, and four metallic peroxides or dioxides have been found effective. These are CaO2, PbO2, MnO2, and SrO2. Barium peroxide is too stable to be an effective oxidizing agent while magnesium peroxide expels oxygen too rapidly for an effective retarder. Other types of organic and inorganic oxidizing agents have not proved beneficial. The fact that an oxidizing action is responsible for retardation of reversion has been demonstrated by the fact that the corresponding mono‐oxides of calcium, strontium, lead, and manganese do not perform in the same manner. In rubber technology the stabilization of vulcanized materials by oxidizing agents is novel, and it appears applicable only in the case of Butyl whose low unsaturation offers greater resistance to oxidation of the chain proper. When CaO2 is added to diene type rubbers such as Buna S, Buna N, and natural rubber the common oxidative effects are accelerated. With the Buna rubbers the hardening action is more rapid, while with natural rubber a softening followed by a hardening action is promoted.A practical illustration of this principle of retarding reversion of Butyl vulcanizates by oxidizing agents has been presented. It has been demonstrated in the laboratory that the service life of automotive tire curing bags made from Butyl can be prolonged by the addition of these metallic dioxides or peroxides to the compound.

Use of Peroxides of Calcium and Magnesium in Determination of Fluorine Content of Soils, Siliceous Materials, and Organics

Journal Article Use of Peroxides of Calcium and Magnesium in Determination of Fluorine Content of Soils, Siliceous Materials, and Organics Get access W H MacIntire, W H MacIntire Search for other works by this author on: Oxford Academic Google Scholar J W Hammond J W Hammond Search for other works by this author on: Oxford Academic Google Scholar Journal of Association of Official Agricultural Chemists, Volume 22, Issue 2, 1 May 1939, Pages 231–236, https://doi.org/10.1093/jaoac/22.2.231a Published: 18 February 2020

1. On Peroxides of Zinc, Cadmium, Magnesium, and Aluminium

1. On Peroxides of Zinc, Cadmium, Magnesium, and Aluminium