Hybrid Gas/Liquid Electrical Discharge Reactors with Zeolites for Colored Wastewater Degradation

2005 ◽  
Vol 8 (2) ◽  
Author(s):  
Hrvoje Kušić ◽  
Natalija Koprivanac ◽  
Igor Peternel ◽  
Bruce R. Locke
Keyword(s):  
Hydrogen Peroxide ◽  
Liquid Phase ◽  
Gas Phase ◽  
Hydroxyl Radicals ◽  
Electrical Discharge ◽  
Organic Dye ◽  
Electrical Discharges ◽  
Colored Wastewater ◽  
Ozone Levels ◽  
Parallel Reactor

AbstractHybrid gas/liquid electrical discharge reactors have been used to degrade an organic dye in the presence and absence of zeolites. Simultaneous gas and liquid phase electrical discharges in the hybrid parallel and hybrid series reactors have been shown in previous work to lead to the formation of hydrogen peroxide and hydroxyl radicals in the liquid phase and ozone in the gas phase. These reactors differ in their electrode configuration, and in previous work it was shown that the ozone levels in the parallel reactor are seven times higher than in the series reactor (3000 ppm and 450 ppm, respectively), while both reactors produce the same levels of hydrogen peroxide (4.9 × 10

scholarly journals Decontamination of N95 and surgical masks using a treatment based on a continuous gas phase-Advanced Oxidation Process

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0248487
Author(s):  
Mahdiyeh Hasani ◽  
Tracey Campbell ◽  
Fan Wu ◽  
Keith Warriner
Keyword(s):  
Hydrogen Peroxide ◽  
Gas Phase ◽  
Hydroxyl Radicals ◽  
Advanced Oxidation Process ◽  
Oxidation Process ◽  
Continuous Process ◽  
Oxidative Polymerization ◽  
Advanced Oxidation ◽  
Surgical Masks ◽  
Uv C

A gas-phase Advanced Oxidation Process (gAOP) was evaluated for decontaminating N95 and surgical masks. The continuous process was based on the generation of hydroxyl-radicals via the UV-C (254 nm) photo-degradation of hydrogen peroxide and ozone. The decontamination efficacy of the gAOP was dependent on the orientation of the N95 mask passing through the gAOP unit with those positioned horizontally enabling greater exposure to hydroxyl-radicals compared to when arranged vertically. The lethality of gAOP was independent of the applied hydrogen peroxide concentration (2–6% v/v) but was significantly (P<0.05) higher when H2O2 was introduced into the unit at 40 ml/min compared to 20 ml/min. A suitable treatment for N95 masks was identified as 3% v/v hydrogen peroxide delivered into the gAOP reactor at 40 ml/min with continuous introduction of ozone gas and a UV-C dose of 113 mJ/cm2 (30 s processing time). The treatment supported >6 log CFU decrease in Geobacillus stearothermophilus endospores, > 8 log reduction of human coronavirus 229E, and no detection of Escherichia coli K12 on the interior and exterior of masks. There was no negative effect on the N95 mask fitting or particulate efficacy after 20 passes through the gAOP system. No visual changes or hydrogen peroxide residues were detected (<1 ppm) in gAOP treated masks. The optimized gAOP treatment could also support >6 log CFU reduction of endospores inoculated on the interior or exterior of surgical masks. G. stearothermophilus Apex spore strips could be applied as a biological indicator to verify the performance of gAOP treatment. Also, a chemical indicator based on the oxidative polymerization of pyrrole was found suitable for reporting the generation of hydroxyl-radicals. In conclusion, gAOP is a verifiable treatment that can be applied to decontaminate N95 and surgical masks without any negative effects on functionality.

scholarly journals Partitioning of hydrogen peroxide in gas-liquid and gas-aerosol phases

2020 ◽  
Author(s):  
Xiaoning Xuan ◽  
Zhongming Chen ◽  
Yiwei Gong ◽  
Hengqing Shen ◽  
Shiyi Chen
Keyword(s):  
Hydrogen Peroxide ◽  
Liquid Phase ◽  
Gas Phase ◽  
Pure Water ◽  
Average Concentration ◽  
Effective Field ◽  
Urban Atmosphere ◽  
Ambient Atmosphere ◽  
Henry's Law ◽  
Henry’S Law

Abstract. Hydrogen peroxide (H2O2) is a vital oxidant in the atmosphere and plays critical roles in the oxidation chemistry of both liquid and aerosol phases. The partitioning of H2O2 between the gas and liquid phase or the aerosol phase could affect its abundance in these condensed phases and eventually the formation of secondary components. However, the partitioning processes of H2O2 in gas-liquid and gas-aerosol phases are still unclear, especially in the ambient atmosphere. In this study, field observations of gas-, liquid-, and aerosol-phase H2O2 were carried out in the urban atmosphere of Beijing during the summer and winter of 2018. The effective field-derived mean value of Henry's law constant (HAm, 2.1 × 105 M atm−1) was 2.5 times that of the theoretical value in pure water (HAt, 8.4 × 104 M atm−1) at 298 ± 2 K. The effective derived gas-aerosol partitioning coefficient (KPm, 3.8 × 10−3 m3 μg−1) was four orders of magnitude higher on average than the theoretical value (KPt, 2.8 × 10−7 M atm−1) at 270 ± 4 K. The partitioning of H2O2 in the gas-liquid and gas-aerosol phases in the ambient atmosphere does not only obey Henry's law or Pankow's absorptive partitioning theory but is also influenced by certain physical and chemical reactions. The average concentration of liquid-phase H2O2 in rainwater during summer was 44.12 ± 26.49 μM. In three-quarters of the collected rain samples, the measured H2O2 was greater than the predicted value in pure water calculated by Henry's law. In these samples, 46 % of the measured H2O2 was from gas-phase partitioning, and most of the rest may have come from residual H2O2 in raindrops. In winter, the level of aerosol-phase H2O2 was 0.093 ± 0.085 ng μg−1, which was much higher than the predicted value based on Pankow's absorptive partitioning theory. Almost all aerosol-phase H2O2 was not from the partitioning of the gas phase. The decomposition/hydrolysis of aerosol-phase organic peroxides could be responsible for 32 % of aerosol-phase H2O2 formation at the maximum rate of 3.65 ng μg−1. Furthermore, the heterogeneous uptake of H2O2 on aerosols contributed to less than 0.5 %.

scholarly journals Effect of textual features and surface properties of activated carbon on the production of hydrogen peroxide from hydroxylamine oxidation

RSC Advances ◽  
2017 ◽  
Vol 7 (41) ◽  
pp. 25305-25313 ◽  
Author(s):  
Wei Song ◽  
Lin Yu ◽  
Xiaowei Xie ◽  
Zhifeng Hao ◽  
Ming Sun ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Activated Carbon ◽  
Liquid Phase ◽  
Gas Phase ◽  
Surface Properties ◽  
Textural Features ◽  
Production Of Hydrogen ◽  
Textual Features

Herein, the textural features and surface properties of activated carbon were mediated by oxidation in the gas-phase or liquid-phase.

Kinetics of the Gas-Phase Recombination Reaction of Hydroxyl Radicals to Form Hydrogen Peroxide†

2009 ◽  
Vol 113 (16) ◽  
pp. 4457-4467 ◽  
Author(s):  
Stig R. Sellevåg ◽  
Yuri Georgievskii ◽  
James A. Miller
Keyword(s):  
Hydrogen Peroxide ◽  
Gas Phase ◽  
Hydroxyl Radicals ◽  
Recombination Reaction ◽  
Kinetics Of

Effects of Electrical Discharges in Low Pressure Gases on the Morphology of Polyethylene Crystals

1974 ◽  
Vol 32 ◽  
pp. 544-545
Author(s):  
L.H. Bolz ◽  
D.H. Reneker
Keyword(s):  
Power Distribution ◽  
Electrical Discharge ◽  
Dielectric Breakdown ◽  
Ionic Species ◽  
Low Pressure ◽  
Polymer Surfaces ◽  
Electrical Discharges ◽  
Adhesive Bonds ◽  
Power Distribution Lines ◽  
Modification Of The Surface

The attack, on the surface of a polymer, by the atomic, molecular and ionic species that are created in a low pressure electrical discharge in a gas is interesting because: 1) significant interior morphological features may be revealed, 2) dielectric breakdown of polymeric insulation on high voltage power distribution lines involves the attack on the polymer of such species created in a corona discharge, 3) adhesive bonds formed between polymer surfaces subjected to such SDecies are much stronger than bonds between untreated surfaces, 4) the chemical modification of the surface creates a reactive surface to which a thin layer of another polymer may be bonded by glow discharge polymerization.

Application of Disk Aerators to Recarbonation of Alkaline Wastewater from Wet Gasification of Carbide

1991 ◽  
Vol 24 (7) ◽  
pp. 277-284 ◽  
Author(s):  
E. Gomólka ◽  
B. Gomólka
Keyword(s):  
Carbon Dioxide ◽  
Liquid Phase ◽  
Gas Phase ◽  
Flue Gas ◽  
Carbonic Acid ◽  
Low Cost ◽  
Flue Gases ◽  
Carbon Dioxide Content ◽  
Patent Claim ◽  
Phase Dispersion

Whenever possible, neutralization of alkaline wastewater should involve low-cost acid. It is conventional to make use of carbonic acid produced via the reaction of carbon dioxide (contained in flue gases) with water according to the following equation: Carbon dioxide content in the flue gas stream varies from 10% to 15%. The flue gas stream may either be passed to the wastewater contained in the recarbonizers, or. enter the scrubbers (which are continually sprayed with wastewater) from the bottom in oountercurrent. The reactors, in which recarbonation occurs, have the ability to expand the contact surface between gaseous and liquid phase. This can be achieved by gas phase dispersion in the liquid phase (bubbling), by liquid phase dispersion in the gas phase (spraying), or by bubbling and spraying, and mixing. These concurrent operations are carried out during motion of the disk aerator (which is a patent claim). The authors describe the functioning of the disk aerator, the composition of the wastewater produced during wet gasification of carbide, the chemistry of recarbonation and decarbonation, and the concept of applying the disk aerator so as to make the wastewater fit for reuse (after suitable neutralization) as feeding water in acetylene generators.

Modeling of aerated upflow fixed bed reactors for nitrification

1999 ◽  
Vol 39 (4) ◽  
pp. 85-92 ◽  
Author(s):  
J. Behrendt
Keyword(s):  
Mathematical Model ◽  
Mass Transfer ◽  
Liquid Phase ◽  
Gas Phase ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Bulk Liquid ◽  
Initial Value ◽  
Fixed Bed Reactors ◽  
Number Of Cells

A mathematical model for nitrification in an aerated fixed bed reactor has been developed. This model is based on material balances in the bulk liquid, gas phase and in the biofilm area. The fixed bed is divided into a number of cells according to the reduced remixing behaviour. A fixed bed cell consists of 4 compartments: the support, the gas phase, the bulk liquid phase and the stagnant volume containing the biofilm. In the stagnant volume the biological transmutation of the ammonia is located. The transport phenomena are modelled with mass transfer formulations so that the balances could be formulated as an initial value problem. The results of the simulation and experiments are compared.

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