scholarly journals The Effect of Adsorbed Volatile Organic Compounds on an Ultrathin Water Film Measurement

2020 ◽  
Vol 10 (17) ◽  
pp. 5981 ◽  
Author(s):  
Shahab Bayani Ahangar ◽  
Chan Ho Jeong ◽  
Fei Long ◽  
Jeffrey S. Allen ◽  
Seong Hyuk Lee ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Surface Treatment ◽  
Organic Compounds ◽  
High Speed ◽  
Water Film ◽  
Water Layer ◽  
Dropwise Condensation ◽  
Air Plasma ◽  
High Speed Imaging ◽  
Volatile Organic

Using surface plasmon resonance imaging (SPRi), we have recently shown for the first time the existence of a monolayer water film between droplets during dropwise condensation. This study examines the effect of adsorbed volatile organic compounds (VOCs) on the ultrathin film measurement using SPRi. Further, the work presents the proper surface-treatment process that enables measurements of the ultrathin water layer during high-speed imaging of dropwise condensation at 3000 frame per second. In this study, two methods were applied for cleaning the surface (gold-coated glass)—(1) standard cleaning procedure (SCP) using acetone, isopropyl alcohol, and deionized water and (2) SCP followed by air plasma cleaning. This work discusses the effect of the cleaning procedures on surface roughness, contact angle, and surface chemistry using atomic force microscopy, optical microscopy, and an X-ray photoelectron spectroscope meter. The results showed that SCP before the SPRi is a proper surface-treatment method. The effect of adsorbed VOCs during dropwise condensation on a surface treated with SCP was measured to be 0.0025 (reflectivity unit), which was 70% smaller than the reflectance associated with a monolayer water film. The results of this work confirm a monolayer water film observation during the dropwise condensation, which has been reported before.

A microfabricated optofluidic ring resonator for sensitive, high-speed detection of volatile organic compounds

Lab on a Chip ◽  
2014 ◽  
Vol 14 (19) ◽  
pp. 3873-3880 ◽  
Author(s):  
Kee Scholten ◽  
Xudong Fan ◽  
Edward T. Zellers
Keyword(s):  
Gas Chromatography ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
High Speed ◽  
Ring Resonator ◽  
Micro Scale ◽  
Volatile Organic

A microfabricated optofluidic ring resonator (μOFRR) sensor is introduced and its utility as a detector for micro-scale gas chromatography is assessed.

scholarly journals Investigation of the relative reactivity of volatile organic compounds in the air plasma of a pulsed corona discharge by the method of competing reactions

2021 ◽  
Vol 2064 (1) ◽  
pp. 012094
Author(s):  
I E Filatov ◽  
V V Uvarin ◽  
E V Nikiforova ◽  
D L Kuznetsov
Keyword(s):  
Volatile Organic Compounds ◽  
Corona Discharge ◽  
Organic Compounds ◽  
Relative Reactivity ◽  
Air Plasma ◽  
Plasma Chemical ◽  
Pulsed Corona Discharge ◽  
Pulsed Corona ◽  
Volatile Organic ◽  
Competing Reactions

Abstract A method for determining the relative reactivity of volatile organic compounds (VOCs) with respect to the air plasma of a pulsed corona discharge is proposed. It is based on the use of specially selected mixtures of organic compounds. The approach is based on the method of competing reactions: all components of the mixture are in equal conditions, so the relative reactivity can be determined with high accuracy using the gas chromatography. The parameters of scaling processes are proposed – plasma chemical yield, relative reactivity, formal reagent as a set of plasma components. In this paper, using the example of a number of VOCs, we demonstrate the extended capabilities of the method using a special technique for processing experimental data. More accurate data on the relative reactivity of a number of VOCs of wide application have been obtained. It is proposed to use the energy yield of ozone as a criterion for the energy efficiency of a plasma chemical installation.

scholarly journals Self-wetting triphase photocatalysis for effective and selective removal of hydrophilic volatile organic compounds in air

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Fei He ◽  
Seunghyun Weon ◽  
Woojung Jeon ◽  
Myoung Won Chung ◽  
Wonyong Choi
Keyword(s):  
Volatile Organic Compounds ◽  
Visible Light ◽  
Organic Compounds ◽  
Periodic Acid ◽  
Water Layer ◽  
Ambient Air ◽  
Strong Electron ◽  
Wide Range ◽  
Volatile Organic

AbstractPhotocatalytic air purification is widely regarded as a promising technology, but it calls for more efficient photocatalytic materials and systems. Here we report a strategy to introduce an in-situ water (self-wetting) layer on WO3 by coating hygroscopic periodic acid (PA) to dramatically enhance the photocatalytic removal of hydrophilic volatile organic compounds (VOCs) in air. In ambient air, water vapor is condensed on WO3 to make a unique tri-phasic (air/water/WO3) system. The in-situ formed water layer selectively concentrates hydrophilic VOCs. PA plays the multiple roles as a water-layer inducer, a surface-complexing ligand enhancing visible light absorption, and a strong electron acceptor. Under visible light, the photogenerated electrons are rapidly scavenged by periodate to produce more •OH. PA/WO3 exhibits excellent photocatalytic activity for acetaldehyde degradation with an apparent quantum efficiency of 64.3% at 460 nm, which is the highest value ever reported. Other hydrophilic VOCs like formaldehyde that are readily dissolved into the in-situ water layer on WO3 are also rapidly degraded, whereas hydrophobic VOCs remain intact during photocatalysis due to the “water barrier effect”. PA/WO3 successfully demonstrated an excellent capacity for degrading hydrophilic VOCs selectively in wide-range concentrations (0.5−700 ppmv).

scholarly journals Droplet evaporation during dropwise condensation due to deposited volatile organic compounds

AIP Advances ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 085202
Author(s):  
Xiongjiang Yu ◽  
Carlos Alberto Dorao ◽  
Maria Fernandino
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Droplet Evaporation ◽  
Dropwise Condensation ◽  
Volatile Organic
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