Solid Peroxides Research Articles

Enzyme‐Mediated Alleviation of Peroxide Toxicity in Self‐Oxygenating Biomaterials (Adv. Healthcare Mater. 13/2022)

3D Bioprinting In article number 2102697 by Jeroen Leijten, Su Ryon Shin, and co-workers, mitigating the toxic effects from solid peroxides in self-oxygenating living tissues is achieved by catalase-mediated hydrolysis of hydrogen peroxide.

Aqueous decomposition behavior of solid peroxides: Effect of pH and buffer composition on oxygen and hydrogen peroxide formation

The ability of solid peroxides to provide sustained release of both oxygen and hydrogen peroxide makes them potentially suitable for oxygen release or antibacterial applications. Most recent reports using solid peroxides to augment oxygen levels do so by compounding solid peroxide powders in polymers to retard the aqueous decomposition. Compounds with peroxidase activity may be added to reduce hydrogen peroxide toxicity. Peroxides are rarely pure and are mixed with oxide and themselves decompose to form hydroxides in water. Therefore, even if buffering strategies are used, locally the pH at the surface of aqueously immersed peroxide particles is inevitably alkaline. Since pH affects the decomposition of peroxides and hydrogen peroxide stability, this study compared for the first-time the aqueous decomposition products of hydrogen and inorganic peroxides that are in use or have been used for medical applications of have been evaluated preclinically; calcium peroxide (CaO2), magnesium peroxide (MgO2), zinc peroxide (ZnO2), sodium percarbonate (Na2CO3.1.5H2O2) and hydrogen peroxide (H2O2). Since plasma can be approximated to be carbonate buffered phosphate solution, we maintained pH using carbonate and phosphate buffers and compared results with citrate buffers. For a given peroxide compound, we identified not only a strong effect of pH but also of buffer composition on the extent to which oxygen and hydrogen peroxide formation occurred. The influence of buffer composition was not previously appreciated, thereby establishing in vitro parameters for better design of intentional release of specific decomposition species. Statement of significanceThis paper compares for the first time the aqueous decomposition products oxygen and hydrogen peroxide of solid peroxy compounds of metal cations, (calcium, magnesium, sodium and zinc) across a pH range that could feasibly be found in the body, (pH 5,7, 9) either physiologically or pathologically. We find that in addition to pH, buffer composition is also a critically important factor, making translation from in vitro models challenging. Cytotoxicity was related to hydrogen peroxide release, alkalinity and in the case of zinc peroxide to the cation itself. In vitro and preclinical studies generally report release data from polymer-peroxide composites and rarely compare peroxides with one another. Together our data provide guidance for oxygen and ROS delivery from these inorganic materials.

Oxygen-Releasing Composites: A Promising Approach in the Management of Diabetic Foot Ulcers.

In diabetes, lower extremity amputation (LEA) is an irreversible diabetic-related complication that easily occurs in patients with diabetic foot ulcers (DFUs). Because DFUs are a clinical outcome of different causes including peripheral hypoxia and diabetic foot infection (DFI), conventional wound dressing materials are often insufficient for supporting the normal wound healing potential in the ulcers. Advanced wound dressing development has recently focused on natural or biocompatible scaffolds or incorporating bioactive molecules. This review directs attention to the potential of oxygenation of diabetic wounds and highlights current fabrication techniques for oxygen-releasing composites and their medical applications. Based on different oxygen-releasable compounds such as liquid peroxides and solid peroxides, for example, a variety of oxygen-releasing composites have been fabricated and evaluated for medical applications. This review provides the challenges and limitations of utilizing current oxygen releasable compounds and provides perspectives on advancing oxygen releasing composites for diabetic-related wounds associated with DFUs.

Microcystis aeruginosa removal by peroxides of hydrogen peroxide, peroxymonosulfate and peroxydisulfate without additional activators

Harmful algal bloom (HAB) is one of the most globally severe challenges in ecological system and water safety. Hydrogen peroxide has been commonly used in the management/treatment. Solid oxidants (e.g., peroxymonosulfate (PMS) and peroxydisulfate (PDS)) may outperform liquid H2O2 due to ease in transportation, handling, and applications. However, the information on applications of PMS and PDS in algae treatment is limited. In this study, the two solid peroxides and H2O2 were investigated for the removal of the blue-green algae of Microcystis aeruginosa. H2O2 and PMS effectively removed algae in 2 d at pH 5.0, 7.0 and 9.0, while PDS was only effective at pH 5.0. The change in pH and the release of dissolved organic carbon were insignificant at 0.2 mM H2O2 and PMS. The PMS could degrade microcystin-LR and phycobiliproteins. The studies of phycobiliproteins degradation and scanning electron microscopy indicated that PMS might cause the cell inactivation mainly by damaging the chemical components in algae cell wall and membrane while H2O2 might mainly enter the cell to form oxidation pressure to kill algae. The scavenger experiments showed that radicals were not crucial in H2O2 and PDS applications. Similarly, the algae removal by PMS was obtained mainly by non-radical pathways; about 77% was direct PMS oxidation and no more than 3% was singlet oxygen-mediated process, while radical pathways of sulfate radical and hydroxyl radical accounted for 18% and 2%, respectively. For the realistic algae-contaminated natural water, the PMS effectively lasted for 60 d, while the H2O2 lasted for 12 d. This research work demonstrates that the PMS is promising in control of HAB. The findings can provide some useful design and application parameters of PMS technology for better management/treatment of algae-contaminated water.

Decomposition Behavior of Solid Peroxides: Effect of Ph, Ions and Buffer Composition

The ability of solid peroxides to provide sustained release of both oxygen and H 2 O 2 as well as other reactive oxygen species makes them potentially suitable for different therapeutic applications. ROS-related therapies and oxygen delivery are the most researched functions of solid peroxides. This study compared for the first-time decomposition products of CaO 2 , MgO 2 , ZnO 2 , Na 2 CO 3 .1.5H 2 O 2 and H 2 O 2 across an extreme pH range that could still be considered relevant to some biological applications (pH 5-9). We identified a strong effect of both pH and buffer type on both the extent of decomposition and decomposition product thereby establishing design parameters for intentional release of specific decomposition species. Cytotoxicity surprisingly was not only related to basicity of metal hydroxides. We discuss factors that are likely to alter decomposition profiles between in vitro and in vivo systems.

Aqueous Decomposition Behavior of Solid Peroxides: Effect of pH and Buffer Composition on Oxygen and Hydrogen Peroxide Formation

The ability of solid peroxides to provide sustained release of both oxygen and hydrogen peroxide makes them potentially suitable for oxygen release or antibacterial applications. Most recent reports using solid peroxides to augment oxygen levels do so by compounding solid peroxide powders in polymers to retard the aqueous decomposition. Compounds with peroxidase activity may be added to reduce hydrogen peroxide toxicity. Peroxides are rarely pure and are mixed with oxide and themselves decompose to form hydroxides in water. Therefore, even if buffering strategies are used, locally the pH at the surface of aqueously immersed peroxide particles is inevitably alkaline. Since pH affects the decomposition of peroxides and hydrogen peroxide stability, this study compared for the first-time the aqueous decomposition products of hydrogen and inorganic peroxides that are in use or have been used for medical applications of have been evaluated preclinically; calcium peroxide (CaO2), magnesium peroxide (MgO2), zinc peroxide (ZnO2), sodium percarbonate (Na2CO3.1.5H2O2) and hydrogen peroxide (H2O2). Since plasma can be approximated to be carbonate buffered phosphate solution, we maintained pH using carbonate and phosphate buffers and compared results with citrate buffers. For a given peroxide compound, we identified not only a strong effect of pH but also of buffer composition on the extent to which oxygen and hydrogen peroxide formation occurred. The influence of buffer composition was not previously appreciated, thereby establishing in vitro parameters for better design of intentional release of specific decomposition species.

3D-Bioprinted Constructs that Breathe

3D-Bioprinted Constructs that Breathe

Solid peroxides in Fenton-like reactions at near neutral pHs: Superior performance of MgO2 on the accelerated reduction of ferric species

Fenton-like reactions at near neutral pHs are limited by the slow reduction of ferric species. Enhancing generation of ▪ from solid peroxides is a promising strategy to accelerate the rate-limiting step. Herein, the H2O2 release and Fenton-like reactions of four solid peroxides, MgO2, CaO2, ZnO2 and urea hydrogen peroxide (UHP), were investigated. Results indicated that UHP can release H2O2 instantly and show a similar behavior as H2O2 in the Fenton-like reactions. MgO2 released H2O2 quickly in phosphate buffered solutions, which was comparable to CaO2 but faster than ZnO2. Metal peroxides induced higher initial phenol degradation rates than UHP and H2O2 when the same theoretic H2O2 dosages and Fe(III)-EDTA were used. MgO2 displayed a superior performance for phenol degradation at pH 5, resulting in more than 93% phenol reduction at 1.5 h. According to kinetic analyses, the generation rate of ▪ in the MgO2 system was 18 and 3.4 times higher than those in ZnO2 and CaO2 systems, respectively. The addition of MgO2 significantly promoted H2O2 based Fenton-like reactions by increasing production of ▪, and the mixture of MgO2 and H2O2 had an improved utilization efficiency of active oxygen than the MgO2 system. The findings suggested the critical roles of metal peroxides in favoring Fenton-like reactions and inspired strategies to simultaneously accelerate Fenton-like reactions and improve utilization efficiency of active oxygen.

Systematic process hazard assessment of three kinds of solid organic peroxides with kinetic analysis and heat transfer equilibrium

Systematic process hazard assessment of three kinds of solid organic peroxides with kinetic analysis and heat transfer equilibrium

Properties of calcium peroxide for release of hydrogen peroxide and oxygen: A kinetics study

Calcium peroxide (CaO2), as one of the solid peroxides, has been increasingly used in contaminated site remediation due to its ability to release oxygen (O2) and hydrogen peroxide (H2O2). Biodegradation can be enhanced by the existence of O2. Hydrogen peroxide can be used to for in situ chemical oxidation via the modified Fenton. Previous studies show inconsistent results about O2 and H2O2 release during CaO2 decomposition. Additionally, the release characteristics of O2 and H2O2 are not evaluated in detail.A series of batch experiments was conducted to investigate the properties of CaO2 decomposition and the release kinetics of O2 and H2O2. O2 and H2O2 were released directly from CaO2 dissolution and H2O2 was not an essential intermediate in the conversion of CaO2 to O2. The two release paths formed a parallel reaction system, with a competitive relationship between the two paths. The release of H2O2 and O2 followed a pseudo-zero-order kinetics pattern and a pseudo-first-order kinetics pattern, respectively. Increasing temperature and decreasing pH could accelerate both O2 and H2O2 release rate. However, increasing temperature could decrease the H2O2 yield and increase the O2 yield, which were similar to the impact of increasing pH.

Decolorization kinetics of Acid Blue 161 by solid peroxides catalyzed by iron in aqueous solution

Decolorization of Acid Blue 161 (AB161) by solid peroxides such as CaO2 and Na2O2 catalyzed by iron in aqueous solution was investigated. The effect of initial pH, concentration of H2O2, Fe2+, and AB161 on the decolorization kinetics was investigated and compared with the results by liquid H2O2. The experimental results show that decolorization of AB161 follows the second-order kinetic. The second decolorization rate constants and oxidation efficiency at different initial pH, Fe2+, H2O2, and AB161 concentration were correlated with dimensionless ratios such as H2O2/Fe2+ or H2O2/AB161. About two dozens of correlation equations are developed in this paper to quantify the effect of the variables on the decolorization rate constants of AB161. Among solid peroxides such as CaO2 and Na2O2 and liquid H2O2, the optimal pH and [Fe2+] are 2.5 and 5.0 × 10−4 mol L−1, while the concentration of CaO2, Na2O2, and H2O2 is 0.30, 0.25 g L−1 and 3.1 × 10−3 mol L−1, respectively. Our experimental results show that decolorization kinetics of AB161 using liquid H2O2 is faster than that using CaO2 and Na2O2 catalyzed by Fe2+, while decolorization rate of AB161 by CaO2 is slightly faster than that by Na2O2 due to the fact that the CaO2 is a fine powder of an average diameter of 0.74 mm and Na2O2 is a particle with an average diameter of 1 mm. Regardless of the solid or liquid peroxide forms, e.g. CaO2, Na2O2, or liquid H2O2, the optimal molar ratio H2O2/Fe2+ of 12 obtained experimentally agreed reasonably with the theoretical predicted value of 11. In addition, the decolorization efficiency, η, is also not affected by the form of peroxides and decreases with the H2O2/AB161 when H2O2, Fe2+, and pH were fixed at 3.1 × 10−3, 5.0 × 10−4 mol L−1, and 2.5, respectively.

Zinc Dioxide Nanoparticulates: A Hydrogen Peroxide Source at Moderate pH

Solid peroxides are a convenient source of hydrogen peroxide, which once released can be readily converted to active oxygen species or to dissolved dioxygen. A zinc peroxide nanodispersion was synthesized and characterized, and its solubility was determined as a function of pH and temperature. We show that zinc peroxide is much more stable in aqueous solutions compared to calcium and magnesium peroxides and that it retains its peroxide content down to pH 6. At low pH conditions H2O2 release is thermodynamically controlled and its dissolution product, Zn(2+), is highly soluble, and thus, hydrogen peroxide release can be highly predictable. The Gibbs free energy of formation of zinc peroxide was found to be -242.0 ± 0.4 kJ/mol and the enthalpy of formation was -292.1 ± 0.7 kJ/mol, substantially higher than theoretically predicted before. The biocidal activity of zinc peroxide was determined by inactivation studies with Escherichia coli cultures, and the activity trend agrees well with the thermodynamic predictions.

Examination of the disinfecting properties of calcium peroxide and its suitability for improving hydrodynamic characteristics of surface water bodies

The fundamental possibility of using solid peroxides of alkaline-earth metals for water disinfection purposes was explored. The maximum peroxide concentration in solution is achieved with addition of a mixture of boric and phosphoric acids. Water treatment with calcium peroxide leads to stable dissolved oxygen levels and improves some hydrochemical characteristics of surface water bodies.

Abstract P117: A Mathematical and Physical Model for Non-Pulmonary Oxygenation for Resuscitation Utilizing Solid Peroxides

Introduction ; Adequate tissue oxygenation is vital for resuscitation. Intravascular O 2 carrying compounds may enhance tissue O 2 delivery under ischemic conditions but use of both hemoglobin and nonhemoglobin O 2 carriers have limitations. Use of compounds capable of producing O 2 at the tissue level may be useful. Solid peroxides such as percarbamide may provide novel means of tissue O 2 delivery since they contain stored O 2 which can be released upon activation with catalase. However, the chemistry is complex and a product must be designed for controlled O 2 production. Objectives : To develop and use a mathematical and physical model to examine the feasibility of creating encapsulated solid peroxides for intravenous O 2 delivery. Methods : An O 2 delivery vehicle combining percarbamide, a non-aqueous liquid carrier, and a biodegradable-compatible polymer coating was developed for controlled O 2 production. Upon contact with plasma, water diffuses across the polymer coating to cause release of H 2 O 2 from percarbamide. The H 2 O 2 then diffuses back across the membrane into plasma reacting with the blood enzyme catalase to form O 2 and water. A permeation cell system was constructed to validate the physical chemistry of this controlled O 2 production approach. A mathematical model incorporating Fickian diffusion and shrinking surface kinetics was derived to model O 2 production. Results : The permeation cell experiments validated the physical chemistry approach of delivering O 2 using encapsulated percarbamide. The mathematical model successfully predicted O 2 release. Experimental and modeling results show that by tuning the coating thickness, coating type, non-aqueous carrier liquid, and solid peroxide size, the rate of O 2 production can be precisely controlled. Percarbamide (150 gms) would produce 250 cc/min of O 2 for 60 minutes to meet whole body metabolic demands. Conclusions : A mathematical and physical model of O 2 production was successfully created allowing manipulation of multiple variables related to releasing O 2 from a solid peroxide delivery system. Experimental results validate the model’s accuracy. This work suggests the feasibility of using encapsulated solid peroxides to produce life sustaining amounts of O 2 for intravenous tissue oxygenation.

Bmim]BF4‐Immobilized Rhenium‐Catalyzed Highly Efficient Oxygenation of Aldimines to Oxaziridines Using Solid Peroxides as Oxidants.

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Bmim]BF 4-immobilized rhenium-catalyzed highly efficient oxygenation of aldimines to oxaziridines using solid peroxides as oxidants

Various rhenium-based catalysts immobilized in [bmim]BF 4 were found to be efficient for oxygenation of various aldimines to the corresponding oxaziridines in excellent yields under mild conditions using solid peroxides like UHP, SPC and SPB as oxidants. Among the various rhenium-based catalysts studied, MTO was found to be most efficient. The reusability and recyclability of MTO immobilized in [bmim]BF 4 was established by using it for three subsequent cycles for oxygenation of benzylidine- tert-butylamine using UHP as oxidant.

Determination of the Enthalpies of Vaporization of Cyclic Organic Peroxides by Correlation of Changes in Gas Chromatographic Retention Times

Liquid and solid cyclic peroxides derived from aliphatic ketones are explosive materials so their enthalpies of vaporization and other thermodynamic or condensed-phase properties cannot be measured directly. In this work the enthalpies of vaporization of peroxides at 298.15 K were estimated simply from gas chromatographic retention times measured at different temperatures. The technique correlates changes in the retention times of compounds whose enthalpies of vaporization are known (called the reference series), with those of the compounds of interest. If tR′ is the adjusted retention time (retention time of each compound minus the retention time of unretained diethyl ether, used as solvent) a plot of ln tR′ against 1/T for each compound (reference compounds and cyclic peroxides) results in a straight line (r2 > 0.99 for all compounds). The enthalpy of transfer from solution to the vapor state (ΔsolgHm) can be obtained by multiplying the slope by the gas constant (R). A second plot correlates the enthalpies of transfer from solution to the vapor state (ΔsolgHm), as measured by gas–liquid chromatography (GLC), with enthalpies of vaporization of reference materials (ΔvapHm at 298.15 K) available in the literature. C9–C15 fatty acid methyl esters and hydrocarbons were used as reference compounds. The enthalpies of vaporization of the cyclic organic peroxides were calculated from the equation of the line obtained in this second correlation, the slope of which was ΔvapHm (at 298.15 K)/ΔgsolHm. The experiments were performed under isothermal conditions with a DB-5 capillary column, flame-ionization detection (FID), and nitrogen as carrier gas. The column temperature was varied over a range of at least 30–70 K between 403 and 473 K, with chromatograms being acquired at 10 K intervals. Enthalpies of vaporization of cyclic organic peroxides are not available in the literature, and the values given in this paper, obtained by gas chromatography, are the first to be reported.

Electric Fields Produced by High-Temperature Metal Oxidation

Transient electric fields of up to 1.5 V were generated during the high temperature oxidation of pure metals (Mg, Al, Ti, Zr, Hf, Cr, Mn, Fe, Co, and Ni) either by gaseous oxygen or by solid peroxides or perchlorates. These time-varying fields are most probably due to ion formation and motion in and behind the moving high temperature reaction zone, which creates an electric double layer within individual particles. The shape and magnitude of the induced temporal electric signal depends upon the reactant properties, mode of the front propagation, and mobility of the ions formed. Unsteady combustion front propagation (occurring during the oxidation of Mg, Al, and Nb) generates an oscillatory electrical signal. Metals belonging to the same group in the periodic table (Ti, Zr, and Hf; Ni and Co) and whose products have the same oxidation state generate qualitatively similar electrical signals. The sign and magnitude of the transient electric potential generated during metal oxidation by perchlorates or peroxides are dominated by the chemoionization processes involved in the decomposition of a solid oxidizer. © 2001 The Electrochemical Society. All rights reserved.

Kinetics and Stoichiometry of Oxygen Release from Solid Peroxides

The increased interest in in situ bioremediation has fostered a commensurate increase in interest in soil chemical amendments. These amendments increase the level of one or more limiting nutrients in the natural environment. Along with the conventional constituents such as nitrogen and phosphorus, oxygen (O2) is an important, often limiting, compound in both flooded and subsurface soils. Chemical formulations have been developed to provide oxygen to these anoxic environments. We evaluated, in distilled water, the release rates of four chemical compounds formulated for the slow release of oxygen that may be used to enhance bioremediation. The release rates were determined by polarographic measurement of the O2 concentration over time in sealed batch reactors. The acquired analog data were converted to digital and logged to a computer. This research addressed the questions of release rates and oxygen-to-solid ratios. Probability of migration into the soil is evaluated on the basis of particle size. We developed a predictive model for the release of oxygen from these solid additives. The four oxidants were sodium percarbonate (Na2Co3 · 1.5H2O2)-encapsulated in polyvinylidene chloride (PVDC); free sodium percarbonate crystals; calcium peroxide (CaO2); and magnesium peroxide (MgO2). The highest calculated release rate was generated by the unencapsulated Na2CO3 · 1.5H2O2 (132 mgl−1h−1). MgO2 had the lowest release rate (1.57 × 10−3 mgl−1h−1). The data indicated that MgO2, or a mix of MgO2 and CaO2, hold the highest promise for use in saturated surface soil applications. Key words: sodium percarbonate; magnesium peroxide; calcium peroxide; oxygen release rates; oxygen-to-solids ratio; bioremediation

The use of solid peroxides to stimulate growth of aerobic microbes in tundra

Solid peroxides and peroxyhydrates degrade into a basic salt, water, and molecular oxygen when in contact with biologically active soils. Column reactors were used to quantify the extent to which three solid peroxides would stimulate growth of aerobic, heterotrophic bacteria and fungi in contaminated tundra soil. Soils in contact with a peroxide compound were incubated in column reactors at field moisture conditions at either 12 or 25°C with no mixing. After 1200-h incubations, localized concentrations of bacteria and fungi were at least 2 orders of magnitude greater in soil amended with sodium carbonate peroxyhydrate than in soil containing either calcium peroxide or magnesium peroxide. Only in soil containing sodium carbonate peroxyhydrate did microbes grow to an appreciably higher concentration than in control soil, which contained no peroxide. Stimulation of both bacterial and fungal growth occurred primarily at distances of less than 5 cm from the peroxide, suggesting that under static moisture conditions, only localized microbial growth can be expected in acidic tundra soils.