Search results for " oxidation"
showing 10 items of 675 documents
Heterogeneous photocatalysis for selective partial oxidation reactions in aqueous suspension
2018
Heterogeneous photocatalysis for selective partial oxidation reactions in aqueous suspension
Monofloral honeys by Sicilian black honeybee (Apis mellifera ssp. sicula) have high reducing power and antioxidant capacity
2016
Thirty samples from thirteen Sicilian monofloral honeys by the local black honeybee, and two honeydew honeys, were studied to assess phenol content, reducing power and antioxidant capacity as well as correlations among these parameters. Honeys from Apiaceae showed the highest phenol amount and capacity to reduce ferric ion and stable chemical radicals, whereas honeys from Leguminosae the lowest. All honeys were active against myoglobin-derived radicals usually formed in red meat after storage and/or heating and significant correlation (p = 0.023) was found between flavonoid content and deactivation rate of this radical. Dill > almond?> tangerine > thistle?> sulla honeys inhibite…
Biopolyester-based systems containing naturally occurring compounds with enhanced thermooxidative stability
2016
Background This work presents a sustainable approach for the stabilization of polylactic acid (PLA) against thermo-oxidative aging. Methods Naturally occurring phenolic and polyphenolic compounds, such as ferulic acid (FerAc), vanillic acid (VanAc), quercetin (Querc) and vitamin E (VitE), were introduced into PLA. Results The preliminary characterization of the systems formulated containing different amounts of natural stabilizers showed that all compounds used acted as plasticizers, leading to a decrease in rheological functions with respect to neat PLA, without significantly modifying the crystallinity of the raw material. The study of the thermo-oxidative behavior of neat PLA and PLA/nat…
Synthesis of polymer nanogels by electro-Fenton process: investigation of the effect of main operation parameters
2017
Recently, electro-Fenton (EF) process has been shown as a promising, facile, effective, low cost and environmentally-friendly alternative for synthesizing polymer nanogels suitable as biocompatible nanocarriers for emerging biomedical applications. Here, the electrochemically-assisted modification of poly(vinylpyrrolidone) (PVP) by EF process was studied to assess the role of key operation parameters for a precise modulation of polymer crosslinking and its functionalization with [sbnd]COOH and succinimide groups. The dimensions of the nanogels, in terms of hydrodynamic radius (Rh) and weight-average molecular weight (Mw), can be tuned up by controlling the electrolysis time, current density…
DFT and kinetic evidences of the preferential CO oxidation pattern of manganese dioxide catalysts in hydrogen stream (PROX)
2022
Abstract The oxidation functionality of Mn(IV) sites has been assessed by density functional theory (DFT) analysis of adsorption and activation energies of CO, H2 and O2 on a model Mn4O8 cluster. DFT calculations indicate that Mn(IV) atoms prompt an easy CO conversion to CO2 via a reaction path involving both catalyst and gas-phase oxygen species, while much greater energy barriers hinder H2 oxidation. Accordingly, a MnCeOx catalyst (Mnat/Ceat, 5) with large exposure of Mn(IV) sites shows a remarkable CO oxidation performance at T ≥ 293 K and no H2 oxidation activity below 393 K. Empiric kinetics disclose that the catalyst-oxygen abstraction step determines both CO and H2 oxidation rate, al…
Combination of advanced oxidation processes and active carbons adsorption for the treatment of simulated saline wastewater
2016
Abstract In the present work, an integrated process combining three different technologies, i.e. heterogeneous photocatalysis, homogeneous ozonation and adsorption on granular activated carbon (GAC) was used for the treatment of a synthetic solution simulating saline wastewater. The synergistic effects between the different methods enhance the oxidation rate of the organic compounds in the integrated process, so that its use may result sustainable. It has been found that a relatively low oxidation rate is sufficient to obtain the highest synergy between the three technologies and to maximize the performances. In particular, coupling ozonation and photocatalysis resulted in 20% enhancement i…
Kinetics of the lipoperoxyl radical-scavenging activity of indicaxanthin in solution and unilamellar liposomes
2007
Abstract The reaction of the phytochemical indicaxanthin with lipoperoxyl radicals generated in methyl linoleate methanol solution by 2,20-azobis(2,4-dimethylvaleronitrile), and in aqueous soybean phosphatidylcholine unilamellar liposomes by 2,20-azobis(2- amidinopropane)hydrochloride, was studied. The molecule acts as a chain-terminating lipoperoxyl radical scavenger in solution, with a calculated inhibition constant of 3.63 £ 105M21 s21, and a stoichiometric factor approaching 2. Indicaxanthin incorporated in liposomes prevented lipid oxidation, inducing clear-cut lag periods and decrease of the propagation rate. Both effects were concentration-dependent, but not linearly related to the p…
Association of redox and inflammation-related biomarkers with prognosis in IgA nephropathy: A prospective observational study.
2022
IgA nephropathy (IGAN) has a variable prognosis. Risk stratification tools are usually based on clinical parameters combined with histologic Oxford-MEST-C score. Circulating redox- and inflammation-related biomarkers may be related to histological changes in IGAN. Therefore, we studied the performance of these biomarkers in predicting the rate of GFR-loss in IGAN.This was an observational prospective study. Fifty-seven stable patients with IGAN were examined at baseline and after a mean observational time of 5.9 ± 1.1 years. The main outcome measure was eGFR-loss per year with predefined groups, stable (1.5 ml/min/1,73 mFifteen patients were in the progressive, 11 in the intermediate, and 3…
Ozonated Water, Ozonated Water, Ozonated Oil and its Products
2018
Most of us are aware that ozone is basically a treatment of pure oxygen and its effect on the human body is even better. As our human body is made up of 70% of water, we used ozone in many different way, one of them is what we know as ozonated water. As ozone when mix in water it diluted thoroughly and highly purifies the water, as it is soluble in water. It maintain its tri-oxygen identity. Biological Properties of Ozonated Water: • It kills viruses, bacteria, fungi and algae on contact. • It breakdown harmful synthetic chemicals into less dangerous molecules. • It purifies the blood by rupturing the cell wall of the microorganisms. …
Pd/Co3O4 catalyst for CH4 emissions abatement: study of SO2 poisoning effect
2007
A catalyst with 0.7 wt% Pd load supported over Co3O4 oxide was investigated in the methane oxidation by operating under CH4/O2 stoichiometric conditions. The effect of the noble metal addition on the activity of bare Co3O4 was evaluated. Samples were characterized by BET, XRD, TPR and XPS analyses. The SO2 poisoning of Pd catalyst and Co3O4 was studied by performing CH4 oxidation tests under stoichiometric conditions in SO2 (1 ppm or 10 ppm). Experiments evidenced that in our conditions the low amount of SO2 doesn’t influence the Pd behaviour, whereas in presence of 10 ppm of SO2 some deactivation occurs that becomes more evident above 450 °C at which the catalyst doesn’t reach 100% of meth…