scholarly journals Novel Materials for Combined Nitrogen Dioxide and Formaldehyde Pollution Control under Ambient Conditions

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1040
Author(s):  
Hugo S. Russell ◽  
James Bonomaully ◽  
Rossana Bossi ◽  
Magdalena E. G. Hofmann ◽  
Hasse C. Knap ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Nitrogen Dioxide ◽  
Pollution Control ◽  
Carbon Adsorbent ◽  
Proton Transfer Reaction ◽  
Control Device ◽  
Urban Environments ◽  
Metal Catalyst ◽  
Ambient Conditions ◽  
Pollution Exposure

Formaldehyde (HCHO) and nitrogen dioxide (NO2) often co-exist in urban environments at levels that are hazardous to health. There is a demand for a solution to the problem of their combined removal. In this paper, we investigate catalysts, adsorbents and composites for their removal efficiency (RE) toward HCHO and NO2, in the context of creating a pollution control device (PCD). Proton-transfer-reaction mass spectrometry and cavity ring-down spectrometry are used to measure HCHO, and chemiluminescence and absorbance-based monitors for NO2. Commercially available and lab-synthesized materials are tested under relevant conditions. None of the commercial adsorbents are effective for HCHO removal, whereas two metal oxide-based catalysts are highly effective, with REs of 81 ± 4% and 82 ± 1%, an improvement on previous materials tested under similar conditions. The best performing material for combined removal is a novel composite consisting of a noble metal catalyst supported on a metal oxide, combined with a treated active carbon adsorbent. The composite is theorized to work synergistically to physisorb and oxidize HCHO and chemisorb NO2. It has an HCHO RE of 72 ± 2% and an NO2 RE of 96 ± 2%. This material has potential as the active component in PCDs used to reduce personal pollution exposure.

scholarly journals Practical Use of Metal Oxide Semiconductor Gas Sensors for Measuring Nitrogen Dioxide and Ozone in Urban Environments

Sensors ◽  
2017 ◽  
Vol 17 (7) ◽  
pp. 1653 ◽  
Author(s):  
Philip Peterson ◽  
Amrita Aujla ◽  
Kirsty Grant ◽  
Alex Brundle ◽  
Martin Thompson ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Nitrogen Dioxide ◽  
Gas Sensors ◽  
Urban Environments ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Semiconductor Gas Sensors

scholarly journals Ambient measurements of aromatic and oxidized VOCs by PTR-MS and GC-MS: intercomparison between four instruments in a boreal forest in Finland

2015 ◽  
Vol 8 (4) ◽  
pp. 3753-3802 ◽  
Author(s):  
M. K. Kajos ◽  
P. Rantala ◽  
M. Hill ◽  
H. Hellén ◽  
J. Aalto ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Boreal Forest ◽  
Proton Transfer Reaction ◽  
Systematic Difference ◽  
Gas Chromatography Mass Spectrometry ◽  
Forest Site ◽  
Ambient Conditions ◽  
Mixing Ratios ◽  
R Value ◽  
Ambient Measurements

Abstract. Proton transfer reaction mass spectrometry (PTR-MS) and gas chromatography mass spectrometry GC-MS) allow real-time measurements of various atmospheric volatile organic compounds (VOC). By taking parallel measurements in ambient conditions, two PTR-MSs and two GC-MSs were studied for their ability to measure methanol, acetaldehyde, acetone, benzene and toluene. The measurements were conducted at a rural boreal forest site in southern Finland between 13 April and 14 May 2012. This paper presents correlations and possible biases between the concentrations measured using the four instruments. This paper presents correlations and possible biases between the concentrations measured using the four instruments. A very good correlation was found for benzene and acetone measurements between all instruments (the mean R value was 0.88 for both compounds), while for acetaldehyde and toluene the correlation was weaker (with a mean R value of 0.50 and 0.62, respectively). For some compounds, notably for methane, there were considerable systematic differences in the mixing ratios measured by the different instruments, despite the very good correlation between the instruments (mean R = 0.90). The systematic difference arises as a difference in the linear regression slope between measurements conducted between instruments, rather than as an offset. This mismatch indicates that the systematic uncertainty in the sensitivity of a given instrument can lead to an uncertainty of 50–100% in the methanol emissions measured by commonly used methods.

scholarly journals Surface Oxygen Vacancies: Dynamics of Photo‐Induced Surface Oxygen Vacancies in Metal‐Oxide Semiconductors Studied Under Ambient Conditions (Adv. Sci. 22/2019)

2019 ◽  
Vol 6 (22) ◽  
pp. 1970132 ◽  
Author(s):  
Daniel Glass ◽  
Emiliano Cortés ◽  
Sultan Ben‐Jaber ◽  
Thomas Brick ◽  
William J. Peveler ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Oxygen Vacancies ◽  
Metal Oxide Semiconductors ◽  
Surface Oxygen ◽  
Ambient Conditions ◽  
Oxide Semiconductors

scholarly journals Dynamics of Photo‐Induced Surface Oxygen Vacancies in Metal‐Oxide Semiconductors Studied Under Ambient Conditions

2019 ◽  
Vol 6 (22) ◽  
pp. 1901841 ◽  
Author(s):  
Daniel Glass ◽  
Emiliano Cortés ◽  
Sultan Ben‐Jaber ◽  
Thomas Brick ◽  
William J. Peveler ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Oxygen Vacancies ◽  
Metal Oxide Semiconductors ◽  
Surface Oxygen ◽  
Ambient Conditions ◽  
Oxide Semiconductors

scholarly journals Markedly enhanced absorption and direct radiative forcing of black carbon under polluted urban environments

2016 ◽  
Vol 113 (16) ◽  
pp. 4266-4271 ◽  
Author(s):  
Jianfei Peng ◽  
Min Hu ◽  
Song Guo ◽  
Zhuofei Du ◽  
Jing Zheng ◽  
...  
Keyword(s):  
Developing Countries ◽  
Black Carbon ◽  
Radiative Forcing ◽  
Urban Environments ◽  
Absorption Enhancement ◽  
Ambient Conditions ◽  
Climatic Impact ◽  
Atmospheric Aging ◽  
Enhanced Absorption ◽  
Direct Radiative Forcing

Black carbon (BC) exerts profound impacts on air quality and climate because of its high absorption cross-section over a broad range of electromagnetic spectra, but the current results on absorption enhancement of BC particles during atmospheric aging remain conflicting. Here, we quantified the aging and variation in the optical properties of BC particles under ambient conditions in Beijing, China, and Houston, United States, using a novel environmental chamber approach. BC aging exhibits two distinct stages, i.e., initial transformation from a fractal to spherical morphology with little absorption variation and subsequent growth of fully compact particles with a large absorption enhancement. The timescales to achieve complete morphology modification and an absorption amplification factor of 2.4 for BC particles are estimated to be 2.3 h and 4.6 h, respectively, in Beijing, compared with 9 h and 18 h, respectively, in Houston. Our findings indicate that BC under polluted urban environments could play an essential role in pollution development and contribute importantly to large positive radiative forcing. The variation in direct radiative forcing is dependent on the rate and timescale of BC aging, with a clear distinction between urban cities in developed and developing countries, i.e., a higher climatic impact in more polluted environments. We suggest that mediation in BC emissions achieves a cobenefit in simultaneously controlling air pollution and protecting climate, especially for developing countries.

Rapid and complete degradation of sulfur mustard adsorbed on M/zeolite-13X supported (M = 5 wt% Mn, Fe, Co) metal oxide catalysts with ozone

RSC Advances ◽  
2016 ◽  
Vol 6 (93) ◽  
pp. 90720-90731 ◽  
Author(s):  
Chowdam Ramakrishna ◽  
Bijendra Kumar Saini ◽  
Krishna Racharla ◽  
Swetha Gujarathi ◽  
Chandra Shekar Sridara ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Sulfur Mustard ◽  
Oxide Catalysts ◽  
Metal Oxide Catalysts ◽  
Ambient Conditions ◽  
Co Catalysts ◽  
Zeolite 13X ◽  
Complete Degradation

Complete degradation of sulfur mustard adsorbed over M/zeolite-13X (M = 5 wt% Mn, Fe, Co) catalysts using ozone gas under ambient conditions.

Sign in / Sign up

Export Citation Format

Share Document