Magnesium Peroxide Research Articles

In-situ growth of magnesium peroxide on the edge of magnesium oxide nanosheets: Ultrahigh photocatalytic efficiency based on synergistic catalysis

Magnesium oxide (MgO) nanosheets and hydrogen peroxide (H2O2) are respectively employed as a photocatalyst and an oxidant to enhance the photocatalytic efficiency for photo-degradation of methylene blue (MB). During the photocatalytic process, highly-oxidizing magnesium dioxide (MgO2) is generated by reacting with H2O2 on the edge of MgO nanosheets, which is verified by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and high-resolution transmission electron microscopy (HR-TEM). The synergistic catalysis of H2O2, MgO2 (highly-oxidizing) and MgO (photocatalysis) has significantly improved the photocatalytic efficiency. The photocatalytic efficiency of MgO nanosheets with H2O2 under visible-light irradiation reaches 98.1%, which is 3.2 times greater than that without H2O2 under visible light (30.5%). Moreover, the photocatalytic efficiency is comparable with that of traditional photocatalysts, such as titanium dioxide (TiO2), graphitic carbon nitride (g-C3N4), etc. This study indicates that the synergistic effect of the homologous oxide catalyst (MgO) effectively improves photo-degradation efficiency via in-situ generating a highly-oxidizing metal peroxide (MgO2) during the photocatalytic process.

Advances in Controlled Oxygen Generating Biomaterials for Tissue Engineering and Regenerative Therapy.

Oxygen (O2) generating biomaterials are emerging as important compositions to improve our capabilities in supporting tissue engineering and regenerative therapeutics. Several in vitro studies demonstrated the usefulness of O2 releasing biomaterials in enhancing cell survival and differentiation. However, more efforts are needed to develop materials that can provide sustained O2 release for the long-term. In this paper, we present different O2 generating sources, including hydrogen peroxide, sodium percarbonate, calcium peroxide and magnesium peroxide, and also cover types of carriers and relevant methods of fabricating O2 generating systems. Then, the applications of O2 generating materials in supporting engineered constructs, supplying high O2 demanding cell transplants, and supporting ischemic tissues are discussed. Moreover, the challenges and future perspectives are highlighted.

Evaluation of biological and enzymatic quorum quencher coating additives to reduce biocorrosion of steel.

Microbial colonization can be detrimental to the integrity of metal surfaces and lead to microbiologically influenced corrosion (MIC). Biocorrosion is a serious problem for aquatic and marine industries in the world. In Minnesota (USA), where this study was conducted, biocorrosion severely affects the maritime transportation industry. The anticorrosion activity of a variety of compounds, including chemical (magnesium peroxide) and biological (surfactin, capsaicin, and gramicidin) molecules were investigated as coating additives. We also evaluated a previously engineered, extremely stable, non-biocidal enzyme known to interfere in bacterial signaling, SsoPox (a quorum quenching lactonase). Experimental steel coupons were submerged in water from the Duluth Superior Harbor (DSH) for 8 weeks in the laboratory. Biocorrosion was evaluated by counting the number and the coverage of corrosion tubercles on coupons and also by ESEM imaging of the coupon surface. Three experimental coating additives significantly reduced the formation of corrosion tubercles: surfactin, magnesium peroxide and the quorum quenching lactonase by 31%, 36% and 50%, respectively. DNA sequence analysis of the V4 region of the bacterial 16S rRNA gene revealed that these decreases in corrosion were associated with significant changes in the composition of bacterial communities on the steel surfaces. These results demonstrate the potential of highly stable quorum quenching lactonases to provide a reliable, cost-effective method to treat steel structures and prevent biocorrosion.

Emission study on MgO2 nano-additive doped biodiesel on immobile diesel engine

ABSTRACT In this present study, the emissions characteristics of a diesel engine fueled with neat rice bran oil biodiesel were investigated. Magnesium dioxide nano-additive is added to neat biodiesel at different concentrations to view its impact on emissions pattern. The obtained results are compared with diesel fuel. Rice bran oil is transesterified into biodiesel and employed in this work. Addition of 20 ppm of MgO2 nanoparticle in rice bran oil biodiesel blend fuel reduces the NOx, HC, CO and smoke emission by 8.2%, 5.7%, 4.6% and 12.6% respectively under peak load condition.

Highly pure MgO2 nanoparticles as robust solid oxidant for enhanced Fenton-like degradation of organic contaminants.

In typical Fenton/Fenton-like reactions, H2O2 was usually used as an oxidant to degrade organic contaminants. However, liquid H2O2 is unstable, easy to decompose and has high biological toxicity especially at high concentration. Herein, highly pure magnesium peroxide (MgO2) nanoparticles were first synthesized and used instead of H2O2 to degrade organic dyes. The structure and morphology of as-prepared products were confirmed by XRD, SEM, TEM and FTIR techniques. The active oxygen content of MgO2 nanoparticles reached up to 26.93 wt%, suggesting a high purity of the as-prepared sample. The degradation performance of MgO2 nanoparticles towards organic contaminants was systematically investigated in the terms of the molar ratio of Fe3+ to MgO2, the dosage of MgO2, initial solution pH and different organic dyes. The results indicated the as-prepared MgO2 exhibited excellent degradation ability to various types of organic dyes. 10 mg of MgO2 nanoparticles could almost completely degrade 200 mL of 20 mg/L methylene blue (MB) in 30 min with a TOC removal rate of 70.2%. The efficient degradation performance was ascribed to the generation of hydroxyl radicals in the MgO2/Fe3+ system. The pathways of MB degradation were also proposed based on the determination of the reaction intermediates.

O2 reduction on a Au film electrode in an ionic liquid in the absence and presence of Mg2+ ions: Product formation and adlayer dynamics.

Aiming at a detailed understanding of the interaction between an ionic liquid, O2, and electrodes in Mg-air batteries, we performed a combined differential electrochemical mass spectrometry and in situ infrared spectroscopy model study on the interaction between the ionic liquid (IL) 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl) imide (BMP-TFSI) and a gold film electrode in the presence and absence of O2 and Mg2+ ions in the potential range relevant for the oxygen reduction reaction (ORR) and evolution reaction. Detailed information on the dynamic exchange of adsorbed ions, on the stability/decomposition of the ionic liquid, and on the activity/selectivity/reversibility of the ORR is derived from measurements performed under potentiodynamic and potentiostatic conditions. In neat BMP-TFSI, we find the dynamics of the potential induced exchange of adsorbed ions to depend significantly on the exchange direction. In the presence of O2, the anions formed in the ORR distinctly affect the adsorption characteristics of the IL ions and the exchange dynamics. Furthermore, the ORR changes from reduction to superoxide anions at moderate potentials to reduction to peroxide anion at more negative potentials. In the additional presence of Mg2+ ions, dominant magnesium peroxide and oxide formation result in an irreversible ORR, in contrast to the requirements of an efficient re-chargeable Mg-air battery. In addition, these ions result in the increasing formation of a blocking adlayer, reducing the coverage of adsorbed IL species.

Application of encapsulated magnesium peroxide (MgO2) nanoparticles in permeable reactive barrier (PRB) for naphthalene and toluene bioremediation from groundwater

One of the challenges in the petroleum hydrocarbon contaminated groundwater remediation by oxygen releasing compounds (ORCs) is to identify the remediation mechanism and determine the impact of ORCs on the environment and the intrinsic groundwater microorganisms. In this research, the application of encapsulated magnesium peroxide (MgO2) nanoparticles in the permeable reactive barrier (PRB) for bioremediation of the groundwater contaminated by toluene and naphthalene was studied in the continuous flow sand-packed plexiglass columns within 50 d experiments. For the biodiversity studies, next generation sequencing (NGS) of the 16S rRNA gene was applied. The results showed that naphthalene was metabolized (within 20 days) faster than toluene (after 30 days) by microorganisms of the aqueous phase. By comparing the contaminant removal in the biotic (which resulted in the complete contaminant removal) and abiotic (around 32% removal for naphthalene and 36% for toluene after 50 d) conditions, the significant role of microorganisms on the decontamination process was proved. Furthermore, the attached microbial communities on the porous media were visualized by scanning electron microscopy (SEM). Microbial community structure analysis by NGS technique revealed that the microbial species which were able to degrade toluene and naphthalene such as P. putida and P. mendocina respectively were stimulated by addition of MgO2 nanoparticles. The presented study resulted in a momentous insight into the application of MgO2 nanoparticles in the hydrocarbon compounds removal from groundwater.

First-Principles Study of Magnesium Peroxide Nucleation for Mg-Air Battery.

Recently, rechargeable non-aqueous Mg-air batteries have gained a lot of interest as the next-generation energy storage device due to the high theoretical volumetric density (3832 Ah L-1 for Mg anode vs. 2062 Ah L-1 for Li), low cost and safety. The field of Mg-air batteries is in the initial stage of development having a limited number of experimental and theoretical reports, in which mainly a carbon cathode is used; however, the information regarding the structural form of carbon is still missing. In this work, using first-principles density functional theory (DFT) calculations, we demonstrate the possibility of graphene and graphite as a cathode material towards Mg-air batteries by studying the initial MgO and MgO2 nucleation processes on the surfaces of graphene and graphite. The calculated free energy diagrams for the redox reactions of oxygen are used to identify the rate-determining step controlling the overpotentials for initial nucleation of MgO and MgO2 . We observe that graphene and graphite surfaces show similar reactivity towards the nucleation of MgO or MgO2 , and the overpotential of the controlling steps for MgO2 nucleation is comparatively less than that of MgO nucleation, which is supported by a recent experimental study, where a higher discharge voltage was observed in a cell having a mixed MgO/MgO2 discharge product than MgO-based cells. Furthermore, the preferable formation of MgO2 cluster compared to MgO on the graphene surface during the ab initio molecular dynamic (AIMD) simulations confirms the selectivity of MgO2 formation over MgO as the final discharge product. We believe that our study will be helpful in understanding the initial nucleation processes during the oxygen reduction reaction (ORR) mechanism and development of suitable cathodes for the future Mg-air batteries.

Application of magnesium peroxide (MgO2) nanoparticles for toluene remediation from groundwater: batch and column studies.

In the present study, magnesium peroxide (MgO2) nanoparticles were synthesized by electro-deposition process and characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The batch experiments were conducted to evaluate the MgO2 half-life (600mg/L) in groundwater under various temperatures (4, 15, and 30°C) and initial pH (3, 7, and 12). The effect of Fe2+ ions (enhanced oxidation) on the toluene remediation by MgO2 was also investigated. Nanoparticles were injected to sand-packed continuous-flow columns, and toluene removal (50ppm) was studied within 50days at 15°C. The results indicated that the half-life of MgO2 at pH3 and 12 were 5 and 15days, respectively, in comparison to 10days at the initial pH7 and 15°C. The nanoparticles showed 20 and 7.5days half-life at 4 and 30°C temperatures, respectively. Injection of Fe2+ ions indicated an impressive effect on toluene removal by MgO2, and the contaminant was completely removed after 5 and 10days, in the batch and column experiments, respectively. Confocal laser scanning microscope (CLSM) analysis indicated that the attached biofilm had a significant role in the decontamination of groundwater. Comparison of bioremediation and enhanced oxidation resulted in a considerable insight into the application of magnesium peroxide in groundwater remediation. Graphical abstract ᅟ.

Electrochemical Formation and Characterization of Surface Blocking Layers on Gold and Platinum by Oxygen Reduction in Mg(ClO4)2 in DMSO

Metal-oxygen batteries employing non-aqueous electrolytes are a promising alternative to conventional lithium-ion batteries due to their high specific energies. One of the most appealing metals in such an application is magnesium, considering its price and its volumetric charge density. While previous reports already indicated the formation of a blocking layer on the oxygen-electrode surface during oxygen reduction, associated with a low reversibility, the reasons for this behavior are not yet understood. This work focuses on elucidating the composition as well as the electrochemical behavior of this blocking layer employing X-ray photoelectron spectroscopy, infrared spectroscopy and measurements with a rotating ring-disc electrode setup. The electrochemical measurements indicate that the blocking layer exhibits an effect similar to the valve effect, which is known from the oxidation of aluminum for example. Combining potentiodynamic and –static measurements, it could be shown that there is a current flow at cathodic potentials due to migration of ions within the layer. A further outcome of the electrochemical measurements is that the anodization of this surface layer proceeds in a self-accelerating manner. The spectroscopic analysis of the surface layer suggests the formation of magnesium peroxide on the surface as well as the presence of some sulfur and chloride containing compounds which must arise from the decomposition of the electrolyte.

Metal peroxide- polymer composites for dye degradation

Semiconductor metal oxides/its composites with polymers have been explored for dye degradation through photocatalytic mechanism; these require UV or visible light for activation. Hence, there is need to develop (photo) catalyst that work in absence/presence of light. Towards this objective we are exploring metal peroxides and its composites for dye degradation. Here, we report our work on magnesium peroxide and its composites for dye degradation by photochemical pathways. The nanocomposites are synthesized from monomers and peroxides. The synthesized composites have been characterized by IR, DRS and powder XRD. The composites did not degrade dyes in dark.

A novel approach to accelerate bacterially induced calcium carbonate precipitation using oxygen releasing compounds (ORCs)

Abstract In the present study, a mixture of oxygen releasing compounds (ORCs) was designed in an attempt to continuously supply dissolved oxygen (DO) in the oxygen-limiting conditions and evaluate bacterially induced calcium carbonate (CaCO3) production. The biomineralization of CaCO3 was adversely affected in the presence of calcium peroxide (CP) and zinc peroxide (ZP), whereas urea-hydrogen peroxide (UP) and magnesium peroxide (MP) were found to be significant on enhancing the biosynthesis of CaCO3. The optimal values for UP and MP obtained from central composite face-centered (CCF) were 1800 mg/L and 8.3 mg/L, respectively. As compared to the control samples, the bacterially induced CaCO3 precipitation was not only enhanced but also accelerated when the optimum concentrations of ORCs were supplemented in the fermentation media. Moreover, the morphology of the precipitated CaCO3 was affected in the presence of ZP, while no such effect was observed when the media were supplemented with CP, UP or MP. The results of this study can be used in many natural and engineered applications such as the constructional purposes for designing a more efficient bio self-healing concrete. The other applications of this innovative technology are the removal of heavy metals, radionuclides and calcium ions contaminants from the environment.

Synthesis and application of magnesium peroxide on cotton fabric for antibacterial properties

An antibacterial agent (MgO2) was synthesised using 0.2 and 0.4 M concentrations of MgCl2·6H2O and H2O2, which was subsequently applied to cotton fabric using a conventional pad-dry-cure method in order to achieve antibacterial properties against S. aureus and E. Coli microorganisms. The antibacterial effect against these microorganisms was investigated using a zone of inhibition test and the percent reduction method. The outcomes of these measurements showed that when the cotton fabric was treated with the reaction product of MgCl2·6H2O and H2O2, it retained 90–93% antibacterial activity against S. aureus and 89–91% against E. coli bacteria. This antibacterial effect against these microorganisms was attributed to the presence of reactive oxygen species and Mg ions on the treated cotton fabric. Long term antibacterial effects against S. aureus and E. coli microorganisms were recorded for up to 70 laundering cycles, and the amounts of retained bound peroxide and Mg ions on the finished specimens were measured using iodimetric titration and MP-AES measurements. Additionally, the properties of synthesised MgO2 crystalline powder and treated cotton fabric were studied using UV–Vis, EDX, FTIR spectroscopy, and SEM measurements. The influence of the MgO2 application on mechanical properties such as tensile strength, tear strength, whiteness index, and crease recovery angle of the treated cotton fabric was also analysed. The results obtained clearly confirmed that the treated cotton fabric possessed antibacterial effects for up to 70 laundering cycles. This is likely due to the presence of the required amount of oxidative species and Mg ions on the treated cotton fabrics. The FTIR and EDX results showed that the presence of these key elements (oxygen containing groups) was responsible for the antibacterial property of the finished fabrics. The whiteness index and tensile strength were improved after treatment with MgO2, although tear strength and flexibility of treated specimens were decreased after treatment.

Microstructural analysis of fracture surfaces and determination of mechanical properties of Al2O3–SiC–MgO nanocomposites

In this study, Alumina (Al2O3) nanopowder associated with different values of silicon carbide nanoparticles (nanoSiC) including 0, 1.5, 3, 4.5, 6, 7.5, 9, 10.5, 12, 13.5 and 15vol% as well as 1 and 2vol% of magnesium dioxide nanoparticles (nanoMgO) were mixed in high-energy ball-mill exposed to isopropanol containing tungsten carbide (WC) balls. Obtained mixture has been dried and got forming process using cold press method. Produced samples have been sintered by hot-press technique at 1700, 1750, 1800, 1850 and 1900°C with a pressure of 30MPa. The impact of reinforcing nanoparticles and sintering temperature on mechanical characteristics of the manufactured samples such as flexural strength, fracture toughness and existing residual stress was examined as well, and their effect on grains and grain boundaries toughness have been examined. Furthermore, fracture behavior and also percentage of transgranular fracture (%PTF) or intergranular fracture were evaluated through studying the fracture surface of the samples. Results showed a considerable increase in flexural strength and fracture toughness by 473.82MPa and 5.29MPa·m1/2, respectively. Moreover, by increasing the volume fraction of reinforcements, in addition to getting finer grains in nanocomposite structures, residual stress and grain boundary toughness have been increased and grain toughness has been decreased. The fracture type was altered from intergranular state when there was no SiC to transgranular state with the increase in SiC in nanocomposite.

Intrinsic Conductivity in Magnesium-Oxygen Battery Discharge Products: MgO and MgO2

Non-aqueous magnesium-oxygen (or ‘Mg-air’) batteries are attractive next generation energy storage devices due to their high theoretical energy densities, low cost, and potential for rechargeability. Prior experiments identified magnesium oxide, MgO, and magnesium peroxide, MgO2, as the primary discharge products in a Mg/O2 cell. Charge transport within these nominally-insulating compounds is expected to limit battery performance, yet these transport mechanisms are either incompletely understood (MgO2) or remain a matter of debate (MgO). The present study characterizes the conductivity associated with intrinsic (point) defects within both compounds using first-principles calculations. For MgO, negative Mg vacancies and hole polarons localized on oxygen anions were identified as the dominant charge carriers. Nevertheless, the large formation energies associated with these carriers suggest that their equilibrium concentrations are low. Furthermore, a large asymmetry exists in the carrier mobility: Mg vacancies are essentially immobile at room temperature, while hole polarons are highly mobile. Importantly, the calculated formation and mobility data for MgO are in remarkable agreement with the three “Arrhenius branches” observed in conductivity experiments, and thus clarify the long-debated transport mechanisms within these regimes. In the case of MgO2, electronic charge carriers alone – electron and hole polarons – are the most prevalent. Similar to MgO, the concentration of carriers in MgO2 is low, and poor mobility further limits conductivity. We conclude that: (i.) sluggish charge transport in MgO or MgO2 will limit battery performance when these compounds cover the cathode support, and (ii.) what little conductivity exists is primarily electronic in nature (i.e., polaron hopping). Artificially increasing the carrier concentration is suggested as a strategy for improving battery performance.

Intrinsic Conductivity in Magnesium–Oxygen Battery Discharge Products: MgO and MgO2

Nonaqueous magnesium–oxygen (or “Mg-air”) batteries are attractive next generation energy storage devices due to their high theoretical energy densities, projected low cost, and potential for rechargeability. Prior experiments identified magnesium oxide, MgO, and magnesium peroxide, MgO2, as the primary discharge products in a Mg/O2 cell. Charge transport within these nominally insulating compounds is expected to limit battery performance; nevertheless, these transport mechanisms either are incompletely understood (in MgO2) or remain a matter of debate (in MgO). The present study characterizes the equilibrium conductivity associated with intrinsic (point) defects within both compounds using first-principles calculations. For MgO, negative Mg vacancies and hole polarons—the latter localized on oxygen anions—were identified as the dominant charge carriers. However, the large formation energies associated with these carriers suggest low equilibrium concentrations. A large asymmetry in the carrier mobility is...

Bulk and surface properties of magnesium peroxide MgO2

Magnesium peroxide has been identified in Mg/air batteries as an intermediate in the oxygen reduction reaction (ORR) [1]. It is assumed that MgO2 is involved in the solid-electrolyte interphase on the cathode surface. Therefore its structure and stability play a crucial role in the performance of Mg/air batteries. In this work we present a theoretical study of the bulk and low-index surface properties of MgO2. All methods give a good account of the experimental lattice parameters for MgO2 and MgO bulk. The reaction energies, enthalpies and free energies for MgO2 formation from MgO are compared among the different DFT methods and with the local MP2 method. A pronounced dependence from the applied functional is found. At variance with a previous theoretical study but in agreement with recent experiments we find that the MgO2 formation reaction is endothermic (HSE06-D3BJ: ΔH=51.9kJ/mol). The stability of low-index surfaces MgO2 (001) (Es=0.96J/m2) and (011) (Es=1.98J/m2) is calculated and compared to the surface energy of MgO (001). The formation energy of neutral oxygen vacancies in the topmost layer of the MgO2 (001) surface is calculated and compared with defect formation energies for MgO (001).

Isomerization of hop extractα-acids

An isomerization process of the α-acids contained in hop extract (with magnesium oxide, potassium hydroxide and magnesium peroxide as catalysts at ambient temperature) was carried out. The influence of two factors (the amount of applied catalyst and the isomerization time) was studied. Ultra-high performance liquid chromatography was used for the evaluation of the isomerization process. The best results were obtained with magnesium oxide. In this case, the influence of the operating variables on the isomerization process and optimal process parameters were determined using statistical methods. The isomerization method described above could be carried out with high efficiency without heating and could be easily adopted and applied on an industrial scale. Copyright © 2016 The Institute of Brewing & Distilling

Stable magnesium peroxide at high pressure.

Rocky planets are thought to comprise compounds of Mg and O as these are among the most abundant elements, but knowledge of their stable phases may be incomplete. MgO is known to be remarkably stable to very high pressure and chemically inert under reduced condition of the Earth’s lower mantle. However, in exoplanets oxygen may be a more abundant constituent. Here, using synchrotron x-ray diffraction in laser-heated diamond anvil cells, we show that MgO and oxygen react at pressures above 96 GPa and T = 2150 K with the formation of I4/mcm MgO2. Raman spectroscopy detects the presence of a peroxide ion (O22−) in the synthesized material as well as in the recovered specimen. Likewise, energy-dispersive x-ray spectroscopy confirms that the recovered sample has higher oxygen content than pure MgO. Our finding suggests that MgO2 may be present together or instead of MgO in rocky mantles and rocky planetary cores under highly oxidized conditions.

Sol – Gel synthesis and characterization of magnesium peroxide nanoparticles

Magnesium peroxide is an excellent source of oxygen in agriculture applications, for instance it is used in waste management as a material for soil bioremediation to remove contaminants from polluted underground water, biological wastes treatment to break down hydrocarbon, etc. In the present study, sol-gel synthesis of magnesium peroxide (MgO2) nanoparticles is reported. Magnesium peroxide is odourless; fine peroxide which releases oxygen when reacts with water. During the sol-gel synthesis, the magnesium malonate intermediate is formed which was then calcinated to obtain MgO2 nanoparticles. The synthesized nanoparticles were characterized using Thermo gravimetric -Differential Thermal Analysis (TG- DTA), X-Ray Diffraction studies (XRD) and High Resolution Transmission Electron Microscope (HRTEM). Our study provides a clear insight that the formation of magnesium malonate during the synthesis was due to the reaction between magnesium acetate, oxalic acid and ethanol. In our study, we can conclude that the calcination temperature has a strong influence on particle size, morphology, monodispersity and the chemistry of the particles.