Showing papers on "Hydrogen peroxide published in 2012"
TL;DR: The high utilization efficiency of H(2)O(2), calculated as 79.2%, showed a promising application of the catalyst in the oxidative degradation of organic pollutants, and the reusability of Fe(3)O (4)/CeO (2) composite was investigated after six successive runs.
Abstract: Magnetic nanoscaled Fe3O4/CeO2 composite was prepared by the impregnation method and characterized as a heterogeneous Fenton-like catalyst for 4-chlorophenol (4-CP) degradation. The catalytic activity was evaluated in view of the effects of various processes, pH value, catalyst addition, hydrogen peroxide (H2O2) concentration, and temperature, and the pseudo-first-order kinetic constant of 0.11 min–1 was obtained for 4-CP degradation at 30 °C and pH 3.0 with 30 mM H2O2, 2.0 g L–1 Fe3O4/CeO2, and 0.78 mM 4-CP. The high utilization efficiency of H2O2, calculated as 79.2%, showed a promising application of the catalyst in the oxidative degradation of organic pollutants. The reusability of Fe3O4/CeO2 composite was also investigated after six successive runs. On the basis of the results of metal leaching, the effects of radical scavengers, intermediates determination, and X-ray photoelectron spectroscopic (XPS) analysis, the dissolution of Fe3O4 facilitated by CeO2 played a significant role, and 4-CP was decom...
913 citations
TL;DR: The photo-catalytic degradation of an azo dye - Amaranth (AM) - has been investigated in TiO(2)/UV aqueous suspensions and it was observed that decolorization rate increased by the increase in temperature and the lower the pH the higher the degradation.
677 citations
TL;DR: Mesoporous nitrogen-doped carbon derived from the ionic liquid N-butyl-3-methylpyridinium dicyanamide is a highly active, cheap, and selective metal-free catalyst for the electrochemical synthesis of hydrogen peroxide that has the potential for use in a safe, sustainable, and cheap flow-reactor-based method for H( 2)O(2) production.
Abstract: Mesoporous nitrogen-doped carbon derived from the ionic liquid N-butyl-3-methylpyridinium dicyanamide is a highly active, cheap, and selective metal-free catalyst for the electrochemical synthesis of hydrogen peroxide that has the potential for use in a safe, sustainable, and cheap flow-reactor-based method for H(2)O(2) production.
560 citations
TL;DR: This study demonstrated a promising approach for the activation of green oxidant, hydrogen peroxide, by the newly-developed polymer photocatalysts for environmental remediation and oxidation catalysis.
Abstract: Semiconducting carbon nitride materials were successfully prepared via a thermal poly-condensation of dicyandiamide as a precursor at >500 °C. The resulting materials were investigated as metal-free catalysts for the activation of H2O2 with visible light under mild conditions, using the decomposition of Rhodamine B (RhB) in aqueous solution as a model reaction. Results revealed that carbon nitride catalysts can activate H2O2 to generate reactive oxy-radicals under visible light irradiation without employment of any metal additives, leading to the mineralization of the dye. Factors affecting the degradation of organic compounds are pH values and the concentration of H2O2. Recycling of the catalyst indicated no obvious deactivation during the entire catalytic reaction, indicating good (photo)chemical stability of metal-free polymeric carbon nitride photocatalysts for environmental purification. This study demonstrated a promising approach for the activation of green oxidant, hydrogen peroxide, by the newly-developed polymer photocatalysts for environmental remediation and oxidation catalysis.
502 citations
TL;DR: Iron copper zeolite (Fe-Cu-ZSM-5) with aqueous hydrogen peroxide is active for the selective oxidation of methane to methanol giving meethanol selectivity and 10 % conversion in a closed catalytic cycle (see scheme).
Abstract: Iron copper zeolite (Fe-Cu-ZSM-5) with aqueous hydrogen peroxide is active for the selective oxidation of methane to methanol. Iron is involved in the activation of the carbon–hydrogen bond, while copper allows methanol to form as the major product. The catalyst is stable, re-usable and activates methane giving >90 % methanol selectivity and 10 % conversion in a closed catalytic cycle (see scheme).
478 citations
TL;DR: This review aims to combine past and novel evidence of interactions between hydrogen peroxide and the microbial cell and its components, while reflecting on alternative applications that make use of gaseous hydrogenperoxide.
Abstract: Hydrogen peroxide is extensively used as a biocide, particularly in applications where its decomposition into
non-toxic by-products is important. Although increasing information on the biocidal efficacy of hydrogen peroxide is available, there is still little understanding of its biocidal mechanisms of action. This review aims to
combine past and novel evidence of interactions between hydrogen peroxide and the microbial cell and its
components, while reflecting on alternative applications that make use of gaseous hydrogen peroxide. It is currently believed that the Fenton reaction leading to the production of free hydroxyl radicals is the basis of hydrogen peroxide action and evidence exists for this reaction leading to oxidation of DNA, proteins and membrane
lipids in vivo. Investigations of DNA oxidation suggest that the oxidizing radical is the ferryl radical formed from
DNA-associated iron, not hydroxyl. Investigations of protein oxidation suggest that selective oxidation of certain
proteins might occur, and that vapour-phase hydrogen peroxide is a more potent oxidizer of protein than liquidphase hydrogen peroxide. Few studies have investigated membrane damage by hydrogen peroxide, though it is
suggested that this is important for the biocidal mechanism. No studies have investigated damage to microbial
cell components under conditions commonly used for sterilization. Despite extensive studies of hydrogen peroxide toxicity, the mechanism of its action as a biocide requires further investigation.
429 citations
TL;DR: In this article, the authors reported the isolation of cellulose whiskers from rice husk by means of an environmental friendly process for cellulose extraction and bleaching, which used the techniques of infrared absorption spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), modulated differential scanning calorimetry (MDSC), and X-ray diffraction (XRD) to obtain cellulose with high purity and crystallinity.
317 citations
TL;DR: In this article, the effect of Gold-nanoparticles on the growth profile and yield of Brassica juncea, under field conditions, was investigated using atomic absorption spectroscopy.
Abstract: Experiments were carried out to determine the effect of Gold-nanoparticles on the growth profile and yield of Brassica juncea, under field conditions. Five different concentrations (0, 10, 25, 50 and 100 ppm) of Gold-nanoparticles were applied through foliar spray. Presence of Gold-nanoparticles in the leaf tissues was confirmed through atomic absorption spectroscopy. Various growth and yield related parameters, including plant height, stem diameter, number of branches, number of pods, seed yield etc. were positively affected by the nanoparticle treatment. Gold-nanoparticle treatment increased the number of leaves per plant; however the average leaf area was not affected. Optimal increase in seed yield was recorded at 10 ppm of Gold-nanoparticle treatment. Reducing as well as total sugar contents increased up to 25 ppm of Gold-nanoparticle treatment. Application of nanoparticles also improved the redox status of the treated plants. The results, for the first time, demonstrate successful use of Gold-nanoparticles in enhancing growth and yield of B. juncea, under actual field conditions and present a viable alternative to GM crops for ensuring food security.
304 citations
TL;DR: L. plantarum C88 isolated from traditional Chinese fermented dairy tofu could be considered as a potential antioxidant to be applied in functional foods.
303 citations
20 Sep 2012
TL;DR: In this protocol, the in situ detection of hydrogen peroxide is described in mature Arabidopsis rosette leaves by staining with 3,3'-diaminobenzidine (DAB) using an adaptation of previous methods.
Abstract: In this protocol, the in situ detection of hydrogen peroxide (one of several reactive oxygen species) is described in mature Arabidopsis rosette leaves by staining with 3,3'-diaminobenzidine (DAB) using an adaptation of previous methods (Thordal-Christensen et al., 1997; Bindschedler et al., 2006; Daudi et al., 2012). DAB is oxidized by hydrogen peroxide in the presence of some haem-containing proteins, such as peroxidases, to generate a dark brown precipitate. This precipitate is exploited as a stain to detect the presence and distribution of hydrogen peroxide in plant cells. The protocol can be modified slightly to detect hydrogen peroxide in different types of plant tissue.
296 citations
TL;DR: This analytical platform not only confirms the intrinsic peroxidase-like activity of the water-soluble cupric oxide nanoparticles, but also shows its great potential applications in environmental chemistry, biotechnology and medicine.
Abstract: Water-soluble cupric oxide nanoparticles are fabricated via a quick-precipitation method and used as peroxidase mimetics for ultrasensitive detection of hydrogen peroxide and glucose. The water-soluble CuO nanoparticles show much higher catalytic activity than that of commercial CuO nanoparticles due to their higher affinity to hydrogen peroxide. In addition, the as-prepared CuO nanoparticles are stable over a wide range of pH and temperature. This excellent stability in the form of aqueous colloidal suspensions makes the application of the water-soluble CuO nanoparticles easier in aqueous systems. A colorimetric assay for hydrogen peroxide and glucose has been established based on the catalytic oxidation of phenol coupled with 4-amino-atipyrine by the action of hydrogen peroxide. This analytical platform not only confirms the intrinsic peroxidase-like activity of the water-soluble cupric oxide nanoparticles, but also shows its great potential applications in environmental chemistry, biotechnology and medicine.
TL;DR: The potential at which the hydrogen peroxide reduction and oxidation reactions are equally likely to occur reflects the intrinsic affinity of the platinum surface for oxygenated species, hereby defined as the "ORR-corrected mixed potential" (c-MP).
Abstract: Understanding the hydrogen peroxide electrochemistry on platinum can provide information about the oxygen reduction reaction mechanism, whether H2O2 participates as an intermediate or not. The H2O2 oxidation and reduction reaction on polycrystalline platinum is a diffusion-limited reaction in 0.1 M HClO4. The applied potential determines the Pt surface state, which is then decisive for the direction of the reaction: when H2O2 interacts with reduced surface sites it decomposes producing adsorbed OH species; when it interacts with oxidized Pt sites then H2O2 is oxidized to O2 by reducing the surface. Electronic structure calculations indicate that the activation energies of both processes are low at room temperature. The H2O2 reduction and oxidation reactions can therefore be utilized for monitoring the potential-dependent oxidation of the platinum surface. In particular, the potential at which the hydrogen peroxide reduction and oxidation reactions are equally likely to occur reflects the intrinsic affinity of the platinum surface for oxygenated species. This potential can be experimentally determined as the crossing-point of linear potential sweeps in the positive direction for different rotation rates, hereby defined as the “ORR-corrected mixed potential” (c-MP).
TL;DR: This Review summarizes the use of metal nanoparticles, either unsupported or deposited on large-surface-area solids, as Fenton catalysts, and particular emphasis is given to the reaction conditions in which these catalysts are used.
Abstract: The Fenton reaction (the generation of hydroxyl radicals from hydrogen peroxide) is the most useful method for degradation of organic pollutants in aqueous solution at moderate concentrations. In this Review we summarize the use of metal nanoparticles, either unsupported or deposited on large-surface-area solids, as Fenton catalysts. The Review complements two other reviews in the field of heterogeneous Fenton catalysis using aluminosilicates and carbonaceous materials. Herein, particular emphasis is given to the reaction conditions in which these catalysts are used, highlighting the operating mechanism and the relative efficiency of the materials. Aspects such as leaching of the metal to the solution, reusability, and the concentration of hydrogen peroxide used are analyzed in detail. Besides a critical description of the present status of the field, future trends and the need to establishing valid comparisons to assess the relative efficiencies of the materials are commented on.
TL;DR: This data imply that Prdx1 can function as a peroxide receptor in response to extracellular H(2)O(2), receiving the peroxide signal and transducing it into a disulfide bond that is subsequently transmitted to the substrate, ASK1, resulting in p38 phosphorylation.
TL;DR: In this paper, the authors described the exploitation of Prussian blue, ferric ferrocyanide (Fe4III[FeII(CN)6]3), for the cathode side in a single-chamber membraneless fuel cell running on hydrogen peroxide (H2O2) as both fuel and oxidant.
Abstract: This communication describes the exploitation of Prussian Blue, ferric ferrocyanide (Fe4III[FeII(CN)6]3), for the cathode side in a single-chamber membraneless fuel cell running on hydrogen peroxide (H2O2) as both fuel and oxidant. An open-circuit voltage (OCV) of 0.6 V has been obtained, which could be the highest OCV with H2O2 ever reported. The maximum power density was 1.55 mW cm−2 which showed a stable long-term operation in acidic media.
TL;DR: Hydrogen peroxide is regarded as an environmentally benign energy carrier because it can be produced by the electrocatalytic two-electron reduction of O2, which is abundant in air, using solar cells; the hydrogen peroxide thus produced could then be readily stored and then used as needed to generate electricity through the use of hydrogenperoxide fuel cells.
01 Jan 2012
TL;DR: In this article, the ORR-corrected mixed potential (c-MP) is defined as the crossing point of linear potential sweeps in the positive direction for different rotation rates.
Abstract: Understanding the hydrogen peroxide electrochemistry on platinum can provide information about the oxygen reduction reaction mechanism, whether H(2)O(2) participates as an intermediate or not. The H(2)O(2) oxidation and reduction reaction on polycrystalline platinum is a diffusion-limited reaction in 0.1 M HClO(4). The applied potential determines the Pt surface state, which is then decisive for the direction of the reaction: when H(2)O(2) interacts with reduced surface sites it decomposes producing adsorbed OH species; when it interacts with oxidized Pt sites then H(2)O(2) is oxidized to O(2) by reducing the surface. Electronic structure calculations indicate that the activation energies of both processes are low at room temperature. The H(2)O(2) reduction and oxidation reactions can therefore be utilized for monitoring the potential-dependent oxidation of the platinum surface. In particular, the potential at which the hydrogen peroxide reduction and oxidation reactions are equally likely to occur reflects the intrinsic affinity of the platinum surface for oxygenated species. This potential can be experimentally determined as the crossing-point of linear potential sweeps in the positive direction for different rotation rates, hereby defined as the "ORR-corrected mixed potential" (c-MP).
TL;DR: This feature article highlights recent advances that have been made in the development of chemosensors of these types for monitoring carbohydrates, dopamine, fluorides, metal ions and hydrogen peroxide.
TL;DR: From a toxicological perspective, potential applications of boronates and other fluorescent probes to high-throughput analyses of peroxynitrite and hydroperoxides in toxicological studies are highlighted.
Abstract: Boronates, a group of organic compounds, are emerging as one of the most effective probes for detecting and quantifying peroxynitrite, hypochlorous acid, and hydrogen peroxide. Boronates react with peroxynitrite nearly a million times faster than with hydrogen peroxide. Boronate-containing fluorogenic compounds have been used to monitor real time generation of peroxynitrite in cells and for imaging hydrogen peroxide in living animals. This perspective highlights potential applications of boronates and other fluorescent probes to high-throughput analyses of peroxynitrite and hydroperoxides in toxicological studies.
TL;DR: The implication is that mononuclear metalloproteins are common targets of H2O2 and that both structural and metabolic arrangements exist to protect them.
TL;DR: The sub-toxic effects of CuO nanoparticles (nano-CuO) were evaluated using three recombinant luminescent Escherichia coli bacteria responding specifically to reactive oxygen species (ROS), single-stranded DNA breaks and bioavailable Cu ions and showed that CuO particles were not involved in these stress responses.
TL;DR: Several organic compounds, including bifuran, quinoline, resorcinol and benzofuranol were removed completely as determined by GC-MS analysis and indicated that biodegradation of the coking wastewater was significantly improved.
TL;DR: A mechanistic kinetic model of the UV/chlorine treatment of TCE showed good agreement with the experimental data, and the pH effect was probably controlled by the increasing concentration of OCl⁻ at higher pH values.
TL;DR: N-nitrosodimethylamine (NDMA) formation potential was observed after treatment with ozone and ozone/peroxide, which highlights the significance of the potential for direct NDMA formation during oxidation in reuse applications.
TL;DR: All of the bleaching treatments were effective in bleaching teeth and that there were no differences between the final color shade results among the treatments.
Abstract: Clinical Relevance For the in-office technique, lower prevalence of tooth sensitivity may be expected when using in-office 38% hydrogen peroxide (HP) agent when compared with the 35% HP agent, whic...
TL;DR: In this paper, a new family of Fenton-type nanocatalysts with interparticle porosity was proposed for the decomposition of H2O2 to reactive hydroxyls.
Abstract: Wet hydrogen peroxide catalytic oxidation (WHPCO) is one of the most important industrially applicable advanced oxidation processes (AOPs) for the decomposition of organic pollutants in water. It is demonstrated that manganese functionalized silicate nanoparticles with interparticle porosity act as a superior Fenton-type nanocatalyst in WHPCO as they can decompose 80% of a test organic compound in 30 minutes at neutral pH and room tem- perature. By using X-ray absorption spectroscopic techniques it is also shown that the superior activity of the nanocatalyst can be attributed uniquely to framework manganese, which decomposes H2O2 to reactive hydroxyls and, unlike manganese in Mn3O4 or Mn2O3 nanoparticles, does not promote the simultaneous decomposition of hydrogen peroxide. The presented material thus introduces a new family of Fenton nanocatalysts, which are environ- mentally friendly, cost-effective, and possess superior efficiency for the decomposition of H2O2 to reactive hydroxyls (AOP), which in turn readily decompose organic pollutants dissolved in water.
TL;DR: This modus operandi is functionally analogous to the SOD/catalase combination, with the advantages of being based on a single and more stable system, and a higher overall efficiency due the physical proximity of the two ROS-reactive centers.
TL;DR: Results showed that higher reaction temperature, hydrogen peroxide concentration and reaction time were the main factors that determined the decrease in Mw of fucoidans with different molecular weights.
TL;DR: This study compares the steady-state concentration of hydroxyl radicals produced by nitrate contained in a conventional WWTP effluent to that produced by typical concentrations of hydrogen peroxide used for advanced oxidation treatment of water.
TL;DR: The mechanism(s) by which hydrogen peroxide is photoproduced by humic substances and chromophoric dissolved organic matter was probed and evidence that the intermediate reacting with O(2) to produce superoxide are relatively long-lived is provided.
Abstract: The mechanism(s) by which hydrogen peroxide (H2O2) is photoproduced by humic substances and chromophoric dissolved organic matter was probed by examining the dependence of the initial H2O2 photoproduction rate (RH2O2) and apparent H2O2 quantum yields on dioxygen concentration for both untreated and borohydride-reduced samples. Although borohydride reduction substantially reduced light absorption, the RH2O2 values were largely unaffected. Apparent monochromatic and polychromatic quantum yields thus increased following reduction. The results indicate that light absorption by charge-transfer states or by (aromatic) ketone/aldehydes does not lead to significant H2O2 photoproduction. High concentrations of triplet quenchers relative to that of dioxygen produced only small decreases (sorbic acid) or small increases (Cl– and Br–) in RH2O2, indicating that neither 1O2 nor excited triplet states of quinones contribute significantly to H2O2 photoproduction. The dependence of RH2O2 on O2 concentration provides evide...