Plasma degradation of trichloroethylene: Process optimization and reaction mechanism analysis

2021 ◽  
Author(s):  
Tian Chang ◽  
Chuanlong Ma ◽  
Anton Yu Nikiforov ◽  
Savita K.P. Veerapandian ◽  
Nathalie De Geyter ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Flow Rate ◽  
Gas Flow ◽  
Discharge Power ◽  
Mechanism Analysis ◽  
Gas Flow Rate ◽  
Chlorinated Volatile Organic Compounds ◽  
Volatile Organic ◽  
Process Factors ◽  
Decomposition Pathway

Abstract In this study, a multi-pin-to-plate negative glow discharge reactor was employed to degrade the hazardous compound, trichloroethylene (TCE). The response surface methodology (RSM) was applied to examine the influences of various process factors (relative humidity (RH), gas flow rate, and discharge power) on the TCE decomposition process, with regard to the TCE removal efficiency, CO2 and CO selectivities. The variance analysis was used to estimate the significance of the single process factors and their interactions. It has been proved that the discharge power had the utmost influential impact on the TCE removal efficiency, CO2 and CO selectivities, subsequently the gas flow rate, and finally RH. Under the optimal conditions with 20.83% RH, 2 W discharge power and 0.5 L·min–1 gas flow rate, the optimal TCE removal efficiency (86.05%), CO2 selectivity (8.62%), and CO selectivity (15.14%) were achieved. In addition, a possible TCE decomposition pathway was proposed based on the investigation of byproducts identified in the exhaust gas of the NTP reactor. This work paves a way for the control of chlorinated volatile organic compounds.

Degradation of Organophosphorus Pesticide in a Packed-Bed Plasma Reactor: Effects of Operating Parameters and Kinetics Study

2013 ◽  
Vol 781-784 ◽  
pp. 1637-1645 ◽  
Author(s):  
Ting Jun Ma ◽  
Yi Qing Xu
Keyword(s):  
Removal Efficiency ◽  
Flow Rate ◽  
Gas Flow ◽  
Plasma Reactor ◽  
Organophosphorus Pesticide ◽  
Packed Bed ◽  
Pulse Frequency ◽  
Gas Flow Rate ◽  
Peak Voltage ◽  
Initial Concentration

The degradation effectiveness and reaction kinetics of representative organophosphorus (OP) pesticide in a packed-bed plasma reactor have been studied. Important parameters, including peak voltage, pulse frequency, gas-flow rate, initial concentration, diameter of catalyst particles, and thickness of catalyst bed which influences the removal efficiency, were investigated. Experimental results indicated that rogor removal efficiency as high as 80% can be achieved at 35 kV with the gas flow rate of 800 mL/min and initial concentration of 11.2 mg/m3.The removal efficiency increased with the increase of pulsed high voltage, and pulse frequency, the decrease of the diameter of catalyst particles and the thickness of catalyst bed. Finally, a model was established to predict the degradation of the rogor, which generally can simulate the experimental measurements to some degree.

Influence Parameters in the Ozonation of Clofibric Acid Using a Cascade Bubble Column

2012 ◽  
Vol 573-574 ◽  
pp. 538-541
Author(s):  
Yan Ping Duan ◽  
Sven Geissen ◽  
Ling Chen
Keyword(s):  
Removal Efficiency ◽  
Flow Rate ◽  
Gas Flow ◽  
Liquid Flow Rate ◽  
Bubble Column ◽  
Continuous Operation ◽  
Clofibric Acid ◽  
Gas Flow Rate ◽  
Toc Removal ◽  
Operation Parameters

Ozonation of clofibric acid (CA) in aqueous solution was carried out under continuous operation in a cascade bubble column. The influence of operation parameters including initial CA concentration, gas flow rate, liquid flow rate and pH on the removal of CA and TOC was investigated. The results indicated that ozonation could be used to effectively remove CA from water. Increasing the initial CA concentration resulted in a decrease of the CA and TOC removal efficiency. A comparison of CA removal efficiency and ozone utilization between cascade and conventional bubble column indicated that cascade bubble column was an effective way for increasing the solubility ozone in the reactor.

scholarly journals The Effect of Mass Transfer Rate-Time in Bubbles on Removal of Azoxystrobin in Water by Micro-Sized Jet Array Discharge

Catalysts ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1169
Author(s):  
Feng Chen ◽  
Dezheng Yang ◽  
Feng Yu ◽  
Yang Kun ◽  
Ying Song
Keyword(s):  
Mass Transfer ◽  
Removal Efficiency ◽  
Flow Rate ◽  
Applied Voltage ◽  
Transfer Rate ◽  
Gas Flow ◽  
Mass Transfer Rate ◽  
Initial Solution ◽  
Solution Temperature ◽  
Gas Flow Rate

In this work, the azoxystrobin removal in water by using a micro-size discharge array was investigated, and the removal efficiency can reach as high as 98.1% after 9 min plasma treatment as well as the energy utilization being only 0.73 g/(kW·h). Based on the relationship between the generation of gas bubbles and parameters of gas-liquid discharge, it was found that the variation of applied voltage, gas flow rate and initial solution temperature could cause particle number change, mass transfer rate change and the mass transfer time change, which significantly affected the practical applications at last. The experimental results indicated that when gas flow rate was 0.7 SLM (Standard Liter per Minute) and the initial solution temperature was 297 K with the applied voltage of 8 kV and discharge frequency of 6 kHz, the removal efficiency of azoxystrobin achieved maximum. Based on the analysis results of liquid mass spectrometry, the removal pathways of azoxystrobin were supposed by the decomposed by-products. Toxicity tests indicated that the decomposed products were safe and non-toxic. So, this study may reveal an azoxystrobin degradation mechanism and provide a safe, reliable and effective way for azoxystrobin degradation.

scholarly journals KLa Determination Using the Effectiveness-NTU Method: Application to Countercurrent Absorbers in Operation Using Viscous Solvents for VOCs Mass Transfer

2019 ◽  
Vol 3 (2) ◽  
pp. 57
Author(s):  
Éric Dumont
Keyword(s):  
Mass Transfer ◽  
Flow Rate ◽  
Gas Flow ◽  
Liquid Flow Rate ◽  
Gas Flow Rate ◽  
Heat Exchanger Design ◽  
Volatile Organic ◽  
Overall Mass Transfer Coefficient ◽  
Viscous Solvents

In this study, the Effectiveness-NTU method, which is usually applied to heat exchanger design, was adapted to gas–liquid countercurrent absorbers to determine the overall mass transfer coefficient, KLa, of the apparatus in operation. It was demonstrated that the ε-NTU method could be used to determine the KLa using the Henry coefficient of the solute to be transferred (HVOC), the gas flow-rate (QG), the liquid flow-rate (QL), the scrubber volume (V), and the effectiveness of the absorber (ε). These measures are calculated from the gaseous concentrations of the solute measured at the absorber inlet (CGin) and outlet (CGout), respectively. The ε-NTU method was validated from literature dedicated to the absorption of volatile organic compounds (VOCs) by heavy solvents. Therefore, this method could be a simple, robust, and reliable tool for the KLa determination of gas–liquid contactors in operation, despite the type of liquid used, i.e., water or viscous solvents.

Evaluation of NOX Removal from Simulated Flue Gas by "Absorption-Oxidation-Reduction" Method

2014 ◽  
Vol 884-885 ◽  
pp. 261-265
Author(s):  
Bao Lin Li ◽  
Ming Yu Li ◽  
Hai Hao Liu ◽  
Gang Cao ◽  
Gang Ren ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Flow Rate ◽  
Flue Gas ◽  
Ferrous Sulfate ◽  
Gas Flow ◽  
Reduction Method ◽  
Ph Value ◽  
Sulfate Solution ◽  
Gas Flow Rate ◽  
Oxidation Reduction

This paper presented a new method of absorption-oxidation-reduction which used ferrous sulfate solution as absorbent, oxygen as oxidizer and urea as reducer to remove NOX from flue gas based on the properties of Fe2+, NO, [Fe (NO)]2+ and urea. These properties included that Fe2+ and NO could produce [Fe (NO)]2+, furthermore [Fe (NO)]2+ was easy to be oxidized by O2, as well as urea can reduce HNO2 and HNO3 in the absorption liquid. This research was to discuss its absorption and removal mechanism with the influence of the initial urea concentration, pH value, initial NOX concentration and gas flow rate on the NOX removal efficiency. The results showed that the removal efficiency of NOX would increase when the initial concentration of urea and NOX increased, while the pH value and gas flow rate decreased.

scholarly journals Purification of the gas after pyrolysis in coupled plasma-catalytic system

2017 ◽  
Vol 19 (4) ◽  
pp. 94-98 ◽  
Author(s):  
Michał Młotek ◽  
Bogdan Ulejczyk ◽  
Joanna Woroszył ◽  
Irmina Walerczak ◽  
Krzysztof Krawczyk
Keyword(s):  
Catalytic System ◽  
Flow Rate ◽  
Gas Flow ◽  
Homogeneous System ◽  
Discharge Power ◽  
Gas Composition ◽  
Gas Flow Rate ◽  
Gliding Discharge ◽  
The One ◽  
Pyrolysis Of Biomass

Abstract Gliding discharge and coupled plasma-catalytic system were used for toluene conversion in a gas composition such as the one obtained during pyrolysis of biomass. The chosen catalyst was G-0117, which is an industrial catalyst for methane conversion manufactured by INS Pulawy (Poland). The effects of discharge power, initial concentration of toluene, gas flow rate and the presence of the bed of the G-0117 catalyst on the conversion of C7H8, a model tars compounds were investigated. Conversion of coluene increases with discharge power and the highest one was noted in the coupled plasma-catalytic system. It was higher than that in the homogeneous system of gliding discharge. When applying a reactor with reduced G-0117 and CO (0.15 mol%), CO2 (0.15 mol%), H2 (0.30 mol%), N2 (0.40 mol%), 4000 ppm of toluene and gas flow rate of 1.5 Nm3/h, the conversion of toluene was higher than 99%. In the coupled plasma-catalytic system with G-0117 methanation of carbon oxides was observed.

scholarly journals Simultaneous removal efficiency of H2S and CO2 by high-gravity rotating packed bed: Experiments and simulation

2021 ◽  
Vol 19 (1) ◽  
pp. 288-298
Author(s):  
Lien Thi Tran ◽  
Tuan Minh Le ◽  
Tuan Minh Nguyen ◽  
Quoc Toan Tran ◽  
Xuan Duy Le ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Flow Rate ◽  
Gas Flow ◽  
Liquid Flow Rate ◽  
Packed Bed ◽  
High Gravity ◽  
Gas Flow Rate ◽  
Solution Ph ◽  
Rotating Speed ◽  
Rotating Packed Bed

Abstract This study explores the possibility of applying high-gravity rotating packed bed (HGRPB) in removing H2S and CO2 from biogas. Ca(OH)2 aqueous solution was used as the absorbent in this study. Different experimental conditions including solution pH, rotating speed (R S) of HGRPB, gas flow rate (Q G), and liquid flow rate (Q L) were investigated with respect to the removal efficiency (E) of H2S and CO2. The experimental and simulated results show that the optimal removal efficiency of H2S and CO2 using HGRPB achieved nearly the same as 99.38 and 99.56% for removal efficiency of H2S and 77.28 and 77.86% for removal efficiency of CO2, respectively. Such efficiencies corresponded with the following optimal conditions: a solution pH of 12.26, HGRPB reactor with the rotating speed of 1,200 rpm, the gas flow rate of 2.46 (L/min), and the liquid flow rate of 0.134 (L/min).

Production of Size-Selected CuXSn1-X Nanoclusters

2011 ◽  
Vol 295-297 ◽  
pp. 70-73 ◽  
Author(s):  
Ahmad I. Ayesh ◽  
Naser Qamhieh ◽  
Saleh Thaker Mahmoud ◽  
Hussain Alawadhi
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Discharge Power ◽  
Inert Gas ◽  
Gas Flow Rate ◽  
Quadrupole Mass ◽  
Gas Condensation ◽  
Operation Conditions ◽  
Source Operation ◽  
Production Mechanisms

Composites of copper–tin (CuxSn1-x) nanoclusters were synthesized using the magnetron dc sputtering gas–condensation technique. Targets with controlled ratios of Sn to Cu were used to produce CuxSn1-xwith different compositions. The effects on the nanocluster size and yield of the sputtering discharge power, inert gas flow rate, and aggregation length were investigated using a quadrupole mass filter. The sputtering discharge power was optimized to maximize the nanocluster yield. The results show that as the inert gas flow rate increases the nanocluster size increases and then decreases. These dependences could be understood in terms of the dominant nanocluster production mechanisms. This work demonstrates the ability of controlling the CuxSn1-xnanoclusters’ size and composition by optimizing the source operation conditions.

Catalytic removal of propene and toluene in air over noble metal catalystThis article is one of a selection of papers published in this Special Issue on Biological Air Treatment.

2009 ◽  
Vol 36 (12) ◽  
pp. 1935-1945 ◽  
Author(s):  
S. Benard ◽  
M. Ousmane ◽  
L. Retailleau ◽  
A. Boreave ◽  
P. Vernoux ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Catalytic Oxidation ◽  
Flow Rate ◽  
Gas Flow ◽  
Fixed Bed ◽  
Gas Flow Rate ◽  
Volatile Organic ◽  
Catalytic Removal ◽  
Selection Of ◽  
Model Reactions

In this paper we present the study of catalytic oxidation of volatile organic compound (VOC) traces in air over Pt/γ-Al2O3 catalysts. The study was carried out using a laboratory fixed-bed catalytic reactor (FBCR) with catalytic oxidation of propene and toluene as model reactions. For better understanding of catalytic activity in a FBCR, the influence of operating parameters such as of platinum (Pt) loading, total gas flow rate, VOC concentration, and oxygen content were studied. The results showed that catalytic activity increases with increase in VOC concentration and a decrease in total gas flow rate. This displayed behaviour is instrumental to working at a low temperature region for complete oxidation of volatile organic compounds.

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