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31.
The objective of this study was to evaluate the performance of a photocatalysis/H2O2/metal membrane hybrid system in the degradation of humic acid. A metal membrane of nominal pore size 0.5 μm was used in the
experiment for separation of TiO2 particles. Hydrogen peroxide was tested as an oxidant. The efficiency of removal of CODCr and color increased rapidly for initial hydrogen peroxide concentrations up to 50 mg L−1. The efficiency of removal of CODCr and color by 50 mg L−1 initial hydrogen peroxide concentration was approximately 95 and 98%, respectively. However, addition of hydrogen peroxide
over 50 mg L−1 inhibited the efficiency of the system. Addition of hydrogen peroxide to a UV/TiO2 system enhanced efficiency of removal of CODCr and color compared with no addition of hydrogen peroxide. This may be ascribed to capture electrons ejected from TiO2 and to the production of OH radicals. Application of the metal membrane in the UV/TiO2/H2O2 system enhanced the efficiency of removal of CODCr and color because of adsorption by the metal membrane surface and the production of OH radicals. By application of a metal
membrane with a nominal pore size of 0.5 μm, TiO2 particles were effectively separated from the treated water by metal membrane rejection. The photocatalytic metal membrane
had much less resistance than the humic acid, TiO2, and humic acid/TiO2 because of the degradation of humic acid by the photocatalytic reaction. 相似文献
32.
A novel tris(2,2′-bipyridine)ruthenium(II) (Ru(bpy)32+) cathodic electrochemiluminescence (ECL) was generated at −0.78 V at the Pt electrode in acetonitrile (ACN), which suggested that the cathodic ECL differed from conventional cathodic ECL. It was found that tripropylamine (TPrA) could enhance this cathodic ECL and the linear range (log-log plot) was 0.2 μM-0.2 mM. In addition, hydrogen peroxide (H2O2) could inhibit the cathodic ECL and was indirectly detected with the linear range of 27-540 μM. The RSD (n = 12) of the ECL intensity in the presence of 135 μM H2O2 was 0.87%. This method was also demonstrated for the fast determination of H2O2 in disinfectant sample and satisfactory results were obtained. 相似文献
33.
Catalytic oxidation of alcohols to carbonyl compounds with hydrogen peroxide using dinuclear iron complexes 总被引:2,自引:0,他引:2
Oxidation of primary and secondary alcohols has been studied in the presence of [Fe(ind)Cl]2O (1) and [Fe2(OMe)2(PAP)Cl4] (2) (indH = 1,3-bis(2′-pyridylimino)isoindoline; PAP = 1,4-di(2′-pyridyl)aminophthalazine) as catalysts using hydrogen peroxide as primary oxidant. The complexes were found to be suitable catalysts for the oxidation of alcohols to the corresponding carbonyl compounds in acetone as solvent. The reactivity of the alcohols is in the order primary < secondary < cyclic secondary < aromatic. The reaction mechanism in the case of 1 probable involves an iron-based oxidant, while in the case of 2 a free-radical mechanism is suggested. 相似文献
34.
Alkanes (cyclohexane, hexane, heptane isomers) are effectively oxidized in CH3CN at 20–70°C by hydrogen peroxide when catalyzed by a Bu4NVO3-pyrazine-2-carboxylic acid system. Alkyl hydroperoxide is the main product; an alcohol and a ketone or an aldehyde are also formed. Under these conditions benzene is oxidized to give phenol, while alkyl benzenes yield oxygenation products both of the ring and the side chain. It has been assumed that the interaction of H2O2 with VO3
– gives rise to generation of HO radicals and other radical-like vanadium containing species that abstract a hydrogen atom from an alkane, RH. The radical R. formed reacts with O2 to produce ROO. which is then transformed to alkyl hydroperoxide.Presented at the VIII International Symposium on Homogeneous Catalysis (Amsterdam, 1992).Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 64–68, January, 1993. 相似文献
35.
An efficient and rapid method for oxidation of electron‐rich aromatic aldehydes to their corresponding carboxylic acids in excellent yields was developed. It is based on the oxidation of methoxy‐substituted benzaldehydes in methanol with an improved aqueous basic hydrogen peroxide system. Benzaldehydes with electron‐withdrawing substituents are oxidized to the corresponding carboxylic acid in excellent yields under mild reaction conditions. 相似文献
36.
A convenient procedure was developed for the synthesis of geminal bishydroperoxides by the sulfuric acid–catalyzed reaction of ketones with hydrogen peroxide in THF. Gem‐bishydroperoxides were prepared by the reactions of five‐ to seven‐membered cycloalkanones without additional purification in 80–95% yields with a purity of more than 95%; their acyclic analogs were prepared in 43–72% yields. 相似文献
37.
Karina González‐Segura Paulina Cañete‐Rosales Rodrigo del Rio Claudia Yáñez Nancy F. Ferreyra Gustavo A. Rivas Soledad Bollo 《Electroanalysis》2012,24(12):2317-2323
The electrochemical response of a glassy carbon electrode modified with carbon nanotubes (CNT) dispersed in two solvents, water and DMF, and two polymers, chitosan and Nafion is reported. The films were homogeneous when the dispersing agent was water or DMF. In the case of polymers, the surfaces present areas with different density of CNTs. A more sensitive electrochemical response was obtained when CNTs are dispersed in the solvents. In the case of CNT dispersed with polymers, the nature of the polymer demonstrated to be a critical parameter not only for dispersing the nanotubes but also for the electrochemical activity of the resulting electrodes. 相似文献
38.
《Analytical letters》2012,45(12):2139-2148
Abstract Hydrogen peroxide can routinely be determined in the presence of ferrocene (FcH) and horseradish peroxidase by monitoring at 617 nm the enzymatically produced ferricenium dye. In contrast, D-glucose can be assayed by following the fading of the ferricenium dye FcH+PF6 ? in the presence of glucose oxidase. The change in absorbance in both cases corresponds to the amount of analyte. viz. H2O2 or D-glucose, in solution. The routine is very simple, invariant to the concentrations of both ferrocenes/ferricenium salt and enzyme and allows numerous “one pot” measuremeats with the detection limit of 10?4 M for both the analytes. It takes 2–4 and 5–10 min to accomplish one analysis of H2O2 and D-glucose in the presence of peroxidase and glucose oxidase, respectively. 相似文献
39.
流动注射胶束电化学发光测定过氧化氢的研究 总被引:6,自引:0,他引:6
建立了一种简易、快速检测过氧化氢的流动注射电化学发光法。本法基于铂丝阳极在 1.3 V(vs.Ag Cl/Ag)时 ,在含有 Na2 CO3 -Na HCO3 缓冲溶液的 KCl支持电解质中现场产生试剂 ,当注入过氧化氢溶液后即产生电化学发光。加入 Triton X-10 0形成的胶束能增强这一体系的发光强度。该法测定过氧化氢的线性范围为 1.0×10 -7~ 1.0× 10 -5 mol/L,对 4.0× 10 -7mol/L的过氧化氢进行 11次测定的相对标准偏差为 2 .6%。用这一方法对雨水中的过氧化氢进行了测定 ,结果满意。 相似文献
40.