Electrophilic Displacement Reactions. VII. Catalysis by Chelating Agents in the Reaction between Hydrogen Peroxide and Benzeneboronic Acid1,2,3

1955 ◽  
Vol 77 (18) ◽  
pp. 4830-4834 ◽  
Author(s):  
Henry G. Kuivila ◽  
Robert A. Wiles
Keyword(s):  
Hydrogen Peroxide ◽  
Chelating Agents ◽  
Displacement Reactions

Effect of H2O2 and DTPA on the characteristics and treatment of TCF (totally chlorine-free) and ECF (elementally chlorine-free) kraft pulping effluents

1997 ◽  
Vol 35 (2-3) ◽  
pp. 163-171 ◽  
Author(s):  
B. C. Larisch ◽  
S. J. B. Duff
Keyword(s):  
Hydrogen Peroxide ◽  
Activated Sludge ◽  
Removal Efficiency ◽  
Chelating Agents ◽  
Reactor Performance ◽  
Pulp Bleaching ◽  
Elemental Chlorine ◽  
Batch Tests ◽  
The Impact ◽  
Bod Removal

Perceived negative environmental effects associated with chlorine bleaching have led to the development and implementation of pulp bleaching technologies which eliminate the use of elemental chlorine (ECF) or any chlorine containing compounds (TCF). Commercial implementation of these technologies has moved forward; however, the research necessary to fully understand the impact of effluents from these new bleaching technologies on the environment and on existing biological treatment processes has lagged behind, and is for many novel bleaching sequences, non-existent. This study examined the impact of hydrogen peroxide (H2O2) and chelating agents on the characteristics and treatment of TCF and ECF kraft effluents. Effluent BOD was reduced approximately 25% by addition of H2O2 concentrations from 20-640 mg/L, however, effluent toxicity was not affected by hydrogen peroxide concentrations of up to 640 mg/L. Unacclimated activated sludge was inhibited by sudden exposure to shock doses of hydrogen peroxide. While the viability of the sludge (as measured by the rate of substrate metabolism) was profoundly affected, the effect was reversible, with full recovery of metabolic activity restored within approximately 10 hours of the shock. In continuous trials, as the activated sludge reactor became acclimated to H2O2, the kinetics of degradation of hydrogen peroxide increased. Chelating agents, particularly diethylene triamine pentaacetic acid (DTPA), were also found to have a dramatic impact on sludge viability and reactor performance. Batch tests indicated a DTPA dose-dependent decrease in oxygen uptake rate. Introduction of DTPA at levels commonly found in TCF effluents to continuous reactors resulted in a disruption of floc structure and a 39% decrease in BOD removal efficiency. Removal of acute toxicity as measured by Microtox was maintained despite the poor BOD removal efficiency.

scholarly journals Visualization and high sensitivity detection of Fe3+ and Cu2+ based on glutathione functionalized gold nanoclusters

2019 ◽  
Vol 80 (12) ◽  
pp. 2233-2240
Author(s):  
Tielong Wang ◽  
Li Li ◽  
Qian Yang ◽  
Weiming Song ◽  
Yang Hou ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Industrial Wastewater ◽  
Chelating Agents ◽  
Gold Nanoclusters ◽  
High Sensitivity ◽  
Selective Detection ◽  
Gold Nanocluster ◽  
High Sensitivity Detection ◽  
H2o2 System ◽  
Sensitivity Detection

Abstract In this paper, a glutathione functionalized gold nanocluster (GSH-AuNCs) was prepared. GSH-AuNCs can catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide to produce a blue-green ox-TMB. By using its peroxidase activity and the GSH-AuNCs-TMB-H2O2 system, the visualization of Fe3+ and Cu2+ and the high sensitivity detection of Fe3+ and Cu2+ can be realized according to the change of absorbance value and color of the system. The results showed that the sensitivity of the system to detect Fe3+ and Cu2+ in industrial wastewater reached 1.25 × 10−9 M and 1.25 × 10−10M, respectively. At the same time, the chelating agents NH4F and EDTA · 2Na were introduced to realize the selective detection of the two ions under the coexistence of Fe3+ and Cu2+ ions.

Peroxidase Localization in Hartmanella Trophozoites

1971 ◽  
Vol 29 ◽  
pp. 346-347 ◽  
Author(s):  
George E. Childs ◽  
Joseph H. Miller
Keyword(s):  
Hydrogen Peroxide ◽  
Ultrastructural Localization ◽  
Pathogenic Strain ◽  
Oxidative Enzymes ◽  
Differential Centrifugation ◽  
Electron Microscopic ◽  
Microscopic Studies ◽  
The Subject ◽  
Axenic Cultures

Biochemical and differential centrifugation studies have demonstrated that the oxidative enzymes of Acanthamoeba sp. are localized in mitochondria and peroxisomes (microbodies). Although hartmanellid amoebae have been the subject of several electron microscopic studies, peroxisomes have not been described from these organisms or other protozoa. Cytochemical tests employing diaminobenzidine-tetra HCl (DAB) and hydrogen peroxide were used for the ultrastructural localization of peroxidases of trophozoites of Hartmanella sp. (A-l, Culbertson), a pathogenic strain grown in axenic cultures of trypticase soy broth.

Fluorescent proteins for in vivo imaging, where's the biliverdin?

2020 ◽  
Vol 48 (6) ◽  
pp. 2657-2667
Author(s):  
Felipe Montecinos-Franjola ◽  
John Y. Lin ◽  
Erik A. Rodriguez
Keyword(s):  
Hydrogen Peroxide ◽  
In Vivo Imaging ◽  
Near Infrared ◽  
Fluorescent Protein ◽  
Fluorescent Proteins ◽  
Fluorescent Imaging ◽  
Infrared Light ◽  
Red Fluorescent Protein ◽  
Color Palette

Noninvasive fluorescent imaging requires far-red and near-infrared fluorescent proteins for deeper imaging. Near-infrared light penetrates biological tissue with blood vessels due to low absorbance, scattering, and reflection of light and has a greater signal-to-noise due to less autofluorescence. Far-red and near-infrared fluorescent proteins absorb light >600 nm to expand the color palette for imaging multiple biosensors and noninvasive in vivo imaging. The ideal fluorescent proteins are bright, photobleach minimally, express well in the desired cells, do not oligomerize, and generate or incorporate exogenous fluorophores efficiently. Coral-derived red fluorescent proteins require oxygen for fluorophore formation and release two hydrogen peroxide molecules. New fluorescent proteins based on phytochrome and phycobiliproteins use biliverdin IXα as fluorophores, do not require oxygen for maturation to image anaerobic organisms and tumor core, and do not generate hydrogen peroxide. The small Ultra-Red Fluorescent Protein (smURFP) was evolved from a cyanobacterial phycobiliprotein to covalently attach biliverdin as an exogenous fluorophore. The small Ultra-Red Fluorescent Protein is biophysically as bright as the enhanced green fluorescent protein, is exceptionally photostable, used for biosensor development, and visible in living mice. Novel applications of smURFP include in vitro protein diagnostics with attomolar (10−18 M) sensitivity, encapsulation in viral particles, and fluorescent protein nanoparticles. However, the availability of biliverdin limits the fluorescence of biliverdin-attaching fluorescent proteins; hence, extra biliverdin is needed to enhance brightness. New methods for improved biliverdin bioavailability are necessary to develop improved bright far-red and near-infrared fluorescent proteins for noninvasive imaging in vivo.

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