scholarly journals Abatement efficiency and fate of EPA-Listed PAHs in aqueous medium under simulated solar and UV-C irradiations, and combined process with TiO2 and H2O2

2020 ◽  
Vol 37 (1) ◽  
pp. 15-27
Author(s):  
Navid Kargar ◽  
Ali Reza Amani-Ghadim ◽  
Amir Abbas Matin ◽  
Golnar Matin ◽  
Hasan Baha Buyukisik
Keyword(s):  
Hydrogen Peroxide ◽  
Titanium Dioxide ◽  
Aqueous Medium ◽  
Time Course ◽  
High Efficiency ◽  
Gas Chromatography Mass Spectrometry ◽  
H2o2 Treatment ◽  
Removal Process ◽  
Xenon Light ◽  
Uv C

Photolytic degradation of dissolved compounds of 16 EPA-Listed PAHs in aqueous medium, exposed to ultraviolet/ titanium dioxide (UV-C/TiO2), xenon light/ titanium dioxide (Xe/TiO2), xenon light/ hydrogen peroxide (Xe/H2O2) and ultraviolet/ hydrogen peroxide (UV-C/H2O2) was studied. The compounds which detected above detection limit of applied analytical method and instrument include: naphthalene (Nap), acenaphthylene (Acy), acenaphthene (Ace), fluorene (Flu), fluoranthene (Fln) and pyrene (Pyr) survived. A time-course experiment (0, 1, 2, 5, 12 min) was performed to determine the fate of PAHs profile along treatments. After accomplishment of the removal process ∑6 PAHs ranked as follow: UV-C/TiO2 > Xe/TiO2 > UV-C > Xe > Xe/H2O2, and UV-C /H2O2 with estimated values of 76.38, 23.02, 22.55, 2.78, 0.00 and 0.00% of the concentration values at the beginning of the treatment, respectively. High efficiency of Xe/H2O2 treatment process (100.00%) at the end of treatment and the structure of residual PAHs which changed to the lighter compounds (2,3-ringed PAHs) before accomplishment of the removal process were proven. Generally, low resistance of Fln to all treatment conditions was observed. Total removal of Nap was considered to be a characteristic PAH compound for completion of the removal of PAHs. Mutate of parent PAH compounds and intermediates were analyzed by gas chromatography-mass spectrometry (GC-MS) and the results suggest the evaluating the toxicity of the treated water due to by-product formation concerns.

scholarly journals Li+ Insertion in Nanostructured TiO2 for Energy Storage

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 21 ◽  
Author(s):  
Mara Serrapede ◽  
Umberto Savino ◽  
Micaela Castellino ◽  
Julia Amici ◽  
Silvia Bodoardo ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Titanium Dioxide ◽  
Energy Storage ◽  
High Efficiency ◽  
Fast Diffusion ◽  
Energy Storage Devices ◽  
Storage Devices ◽  
Residual Hydrogen ◽  
Energy Conversion And Storage ◽  
And Storage

Nanostructured materials possess unique physical-chemical characteristics and have attracted much attention, among others, in the field of energy conversion and storage devices, for the possibility to exploit both their bulk and surface properties, enabling enhanced electron and ion transport, fast diffusion of electrolytes, and consequently high efficiency in the electrochemical processes. In particular, titanium dioxide received great attention, both in the form of amorphous or crystalline material for these applications, due to the large variety of nanostructures in which it can be obtained. In this paper, a comparison of the performance of titanium dioxide prepared through the oxidation of Ti foils in hydrogen peroxide is reported. In particular, two thermal treatments have been compared. One, at 150 °C in Ar, which serves to remove the residual hydrogen peroxide, and the second, at 450 °C in air. The material, after the treatment at 150 °C, results to be not stoichiometric and amorphous, while the treatment at 450 °C provide TiO2 in the anatase form. It turns out that not-stoichiometric TiO2 results to be a highly stable material, being a promising candidate for applications as high power Li-ion batteries, while the anatase TiO2 shows lower cyclability, but it is still promising for energy-storage devices.

scholarly journals Kinetic resolution of indolines by asymmetric hydroxylamine formation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Gang Wang ◽  
Ran Lu ◽  
Chuangchuang He ◽  
Lei Liu
Keyword(s):  
Hydrogen Peroxide ◽  
Chemical Synthesis ◽  
Late Stage ◽  
Kinetic Resolution ◽  
High Efficiency ◽  
Bond Formation ◽  
Bioactive Molecules ◽  
Environmentally Benign ◽  
Secondary Amines

AbstractCatalytic kinetic resolution of amines represents a longstanding challenge in chemical synthesis. Here, we described a kinetic resolution of secondary amines through oxygenation to produce enantiopure hydroxylamines involving N–O bond formation. The economic and practical titanium-catalyzed asymmetric oxygenation with environmentally benign hydrogen peroxide as oxidant is applicable to a range of racemic indolines with multiple stereocenters and diverse substituent patterns in high efficiency with efficient chemoselectivity and enantio-discrimination. Late-stage asymmetric oxygenation of bioactive molecules that are otherwise difficult to synthesize was also explored.

scholarly journals Biodegradation and metabolic pathway of fenvalerate by Citrobacter freundii CD-9

AMB Express ◽  
2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jie Tang ◽  
Dan Lei ◽  
Min Wu ◽  
Qiong Hu ◽  
Qing Zhang
Keyword(s):  
Environmental Pollution ◽  
Environmental Remediation ◽  
High Efficiency ◽  
Mass Spectrometry Analysis ◽  
Gas Chromatography Mass Spectrometry ◽  
Citrobacter Freundii ◽  
16S Rrna Sequence ◽  
Intracellular Enzyme ◽  
Pyrethroid Insecticides ◽  
Spectrometry Analysis

Abstract Fenvalerate is a pyrethroid insecticide with rapid action, strong targeting, broad spectrum, and high efficiency. However, continued use of fenvalerate has resulted in its widespread presence as a pollutant in surface streams and soils, causing serious environmental pollution. Pesticide residues in the soil are closely related to food safety, yet little is known regarding the kinetics and metabolic behaviors of fenvalerate. In this study, a fenvalerate-degrading microbial strain, CD-9, isolated from factory sludge, was identified as Citrobacter freundii based on morphological, physio-biochemical, and 16S rRNA sequence analysis. Response surface methodology analysis showed that the optimum conditions for fenvalerate degradation by CD-9 were pH 6.3, substrate concentration 77 mg/L, and inoculum amount 6% (v/v). Under these conditions, approximately 88% of fenvalerate present was degraded within 72 h of culture. Based on high-performance liquid chromatography and gas chromatography-mass spectrometry analysis, ten metabolites were confirmed after the degradation of fenvalerate by strain CD-9. Among them, o-phthalaldehyde is a new metabolite for fenvalerate degradation. Based on the identified metabolites, a possible degradation pathway of fenvalerate by C. freundii CD-9 was proposed. Furthermore, the enzyme localization method was used to study CD-9 bacteria and determine that its degrading enzyme is an intracellular enzyme. The degradation rate of fenvalerate by a crude enzyme solution for over 30 min was 73.87%. These results showed that strain CD-9 may be a suitable organism to eliminate environmental pollution by pyrethroid insecticides and provide a future reference for the preparation of microbial degradation agents and environmental remediation.

scholarly journals Enhanced Performance of Hydrogen Peroxide Modified Pozzolan-Based Geopolymer for Abatement of Methylene Blue from Aqueous Medium

Silicon ◽  
2021 ◽  
Author(s):  
Dzoujo T. Hermann ◽  
Sylvain Tome ◽  
Victor O. Shikuku ◽  
Jean B. Tchuigwa ◽  
Alex Spieß ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Methylene Blue ◽  
Aqueous Medium

Sanitization of Chicken Frames by a Combination of Hydrogen Peroxide and UV Light To Reduce Contamination of Derived Edible Products

2019 ◽  
Vol 82 (11) ◽  
pp. 1896-1900
Author(s):  
A. M. JONES-IBARRA ◽  
C. Z. ALVARADO ◽  
CRAIG D. COUFAL ◽  
T. MATTHEW TAYLOR
Keyword(s):  
Hydrogen Peroxide ◽  
Salmonella Enterica ◽  
Advanced Oxidation Process ◽  
Uv Light ◽  
Disease Outbreaks ◽  
Aerobic Bacteria ◽  
Chicken Carcass ◽  
Serovar Typhimurium ◽  
Uv C ◽  
Water Rinse

ABSTRACT Chicken carcass frames are used to obtain mechanically separated chicken (MSC) for use in other further processed food products. Previous foodborne disease outbreaks involving Salmonella-contaminated MSC have demonstrated the potential for the human pathogen to be transmitted to consumers via MSC. The current study evaluated the efficacy of multiple treatments applied to the surfaces of chicken carcass frames to reduce microbial loads on noninoculated frames and frames inoculated with a cocktail of Salmonella enterica serovar Enteritidis and Salmonella enterica serovar Typhimurium. Inoculated or noninoculated frames were left untreated (control) or were subjected to treatment using a prototype sanitization apparatus. Treatments consisted of (i) a sterile water rinse, (ii) a water rinse followed by 5 s of UV-C light application, or (iii) an advanced oxidation process (AOP) combining 5 or 7% (v/v) hydrogen peroxide (H2O2) with UV-C light. Treatment with 7% H2O2 and UV-C light reduced numbers of aerobic bacteria by up to 1.5 log CFU per frame (P < 0.05); reductions in aerobic bacteria subjected to other treatments did not statistically differ from one another (initial mean load on nontreated frames: 3.6 ± 0.1 log CFU per frame). Salmonella numbers (mean load on inoculated, nontreated control was 5.6 ± 0.2 log CFU per frame) were maximally reduced by AOP application in comparison with other treatments. No difference in Salmonella reductions obtained by 5% H2O2 (1.1 log CFU per frame) was detected compared with that obtained following 7% H2O2 use (1.0 log CFU per frame). The AOP treatment for sanitization of chicken carcass frames reduces microbial contamination on chicken carcass frames that are subsequently used for manufacture of MSC.

Sign in / Sign up

Export Citation Format

Share Document