Photocatalytic Degradation of Gaseous Formaldehyde by Modified Hierarchical TiO2 Nanotubes at Room Temperature

2016 ◽  
Vol 69 (3) ◽  
pp. 343 ◽  
Author(s):  
Di Gu ◽  
Baohui Wang ◽  
Yanji Zhu ◽  
Hongjun Wu
Keyword(s):  
Indoor Air ◽  
Room Temperature ◽  
Air Pollutant ◽  
Noble Metal Nanoparticles ◽  
Reaction Rate Constants ◽  
Volatile Organic ◽  
Major Process ◽  
Formaldehyde Degradation ◽  
Tio2 Nts ◽  
Gaseous Formaldehyde

As a major indoor air pollutant, formaldehyde released from building and furnishing materials is one of the main volatile organic compounds (VOCs). Hierarchical TiO2 nanotube arrays (TiO2 NTs) prepared via a facile two-step anodization showed excellent photocatalytic (PC) degradation of formaldehyde at room temperature. Modification with noble metal nanoparticles (NMNs) could further improve the PC activity of TiO2 NTs. The final products of formaldehyde degradation were detected to be CO2 and H2O, which indicated that the mineralization of formaldehyde was the major process in this PC reaction. The reaction rate constants (k) determined for the three catalysts were in the order kTiO2 NTs < kAu/TiO2 NTs < kPt/TiO2 NTs (Pt/TiO2 NTs had the highest PC ability). The significant enhancement of PC performance can be ascribed to the formation of a Schottky junction between the NMNs and TiO2 NTs.

scholarly journals Ag Nanoparticles Sensitized In2O3 Nanograin for the Ultrasensitive HCHO Detection at Room Temperature

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Shiqiang Zhou ◽  
Mingpeng Chen ◽  
Qingjie Lu ◽  
Yumin Zhang ◽  
Jin Zhang ◽  
...  
Keyword(s):  
Indoor Air ◽  
Ag Nanoparticles ◽  
Room Temperature ◽  
Unsolved Problem ◽  
Air Pollutant ◽  
Ag Nps ◽  
Performance Targets ◽  
Fabrication Cost ◽  
Low Concentrations ◽  
Stringent Performance

AbstractFormaldehyde (HCHO) is the main source of indoor air pollutant. HCHO sensors are therefore of paramount importance for timely detection in daily life. However, existing sensors do not meet the stringent performance targets, while deactivation due to sensing detection at room temperature, for example, at extremely low concentration of formaldehyde (especially lower than 0.08 ppm), is a widely unsolved problem. Herein, we present the Ag nanoparticles (Ag NPs) sensitized dispersed In2O3 nanograin via a low-fabrication-cost hydrothermal strategy, where the Ag NPs reduces the apparent activation energy for HCHO transporting into and out of the In2O3 nanoparticles, while low concentrations detection at low working temperature is realized. The pristine In2O3 exhibits a sluggish response (Ra/Rg = 4.14 to 10 ppm) with incomplete recovery to HCHO gas. After Ag functionalization, the 5%Ag-In2O3 sensor shows a dramatically enhanced response (135) with a short response time (102 s) and recovery time (157 s) to 1 ppm HCHO gas at 30 °C, which benefits from the Ag NPs that electronically and chemically sensitize the crystal In2O3 nanograin, greatly enhancing the selectivity and sensitivity.

scholarly journals Measurements of Indoor Air Pollutant Levels in a University Office Building

2007 ◽  
Vol 2 (4) ◽  
pp. 123-129 ◽  
Author(s):  
João F.P Gomes ◽  
J. C. M Bordado ◽  
Georgina Sarmento ◽  
José Dias
Keyword(s):  
Indoor Air ◽  
Chemical Species ◽  
Air Pollutant ◽  
Total Volatile ◽  
Organic Species ◽  
Pollutant Concentrations ◽  
Volatile Organic ◽  
Specific Individual ◽  
Total Volatile Organic Compounds ◽  
Indoor And Outdoor

This work consisted of a series of determinations performed in typical rooms of a building belonging to the Technical University of Lisbon, which is located in a central urban area of Lisbon. The main objective was to evaluate the Indoor Air Quality (IAQ) of the rooms so that further corrective measures could be taken if unsatisfactory IAQ levels were to be found. Correlations were derived, between indoor and outdoor pollutant concentrations, in order to assess the existence of contaminations coming from outside. Also, correlations were derived between total volatile organic compounds (VOC) concentrations and specific individual organic species measured in the same room. The methodology recorded in this paper is effective to assess compliance analysis of total VOCs, however, it seems somewhat limited to determine specific individual chemical species responsible for obtaining high total VOC concentrations.

scholarly journals Assessment of residential exposure to Volatile Organic Compounds (VOCs) and Carbon Dioxide (CO2)

2018 ◽  
Vol 19 (4) ◽  
pp. 726-732
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Indoor Air ◽  
Indoor Air Pollution ◽  
Consumer Products ◽  
Air Pollutant ◽  
Outdoor Environment ◽  
Residential Exposure ◽  
Volatile Organic ◽  
Potential Sources

There is increasing concern about indoor air pollution worldwide due to its adverse health effects. One of the predominant indoor air pollutant groups is assumed to be volatile organic compounds (VOCs), including a variety of hydrocarbons with different functional groups. Among VOCs, some species have carcinogenic effects, and some are widely used in many consumer products. CO2 is assumed to be an indicator of ventilation adequacy. Thus, elevated indoor CO2 levels are linked with the discomfort level of occupants. Residential exposure to VOCs and CO2 in 6 different homes located in 3 different towns in Canakkale, Turkey were assessed for about a year. Also, a home inventory was used to identify the potential sources of VOCs and CO2 as well as environmental concerns of the occupants. The highest levels of indoor CO2, total volatile organic compounds (TVOC), benzene, toluene, and xylenes were found at industrial sampling sites. A connection between aspects of the outdoor environment (i.e. availability of potential sources) and residential exposure to air pollutants was found. Also, some activities (e.g. heating fuel type, house cleaning frequency, etc.) and factors (e.g. characteristics of the outdoor environment) influenced residential exposure to VOCs and CO2.

Evaluation of common indoor air pollutant reduction by a botanical indoor air biofilter system

2019 ◽  
Vol 30 (1) ◽  
pp. 7-21
Author(s):  
Izdihar Zahirah Ibrahim ◽  
Wen Tong Chong ◽  
Sumiani Yusoff ◽  
Chin-Tsan Wang ◽  
Xianbo Xiang ◽  
...  
Keyword(s):  
Indoor Air ◽  
Air Pollutants ◽  
Market Research ◽  
Ventilation System ◽  
Air Pollutant ◽  
Growth Media ◽  
Volatile Organic ◽  
Pollutant Reduction ◽  
Indoor Air Pollutants ◽  
Alternative Solutions

Indoor air pollutant issues have attracted various researchers to investigate alternative solutions to non-biofiltration systems, such as common air purifiers that are generally used in the market. Research has found that active botanical biofilter systems are efficient in filtering indoor air pollutants, as well as providing a refreshing environment to surroundings. The research presented here describes a developed prototype of a botanical indoor air biofilter (BIAB) and evaluates the performance of the BIAB system in reducing common indoor air pollutants. The system was assessed for its single-pass filtration across an aerosol containing particles with the diameter of 2.5 µm (PM2.5), 10 µm (PM10) and volatile organic compounds (VOCs) by burning aromatic cone incense. The system comprises three working sections: a fraction of horizontally grown plants with growth media as the botanical biofiltration section, an evaporative medium (an additional component from a commercial active botanical biofilter) and a mechanical ventilation system that supplies cleaned air to the surroundings. The BIAB system recorded the removal efficiencies of 54.5 ± 6.04% for PM2.5, 65.42 ± 9.27% for PM10 and 46 ± 4.02% for VOCs.

SnS2/MXene derived TiO2 hybrid for ultra-fast room temperature NO2 gas sensing

2021 ◽  
Author(s):  
Tianding CHEN ◽  
Wenhao YAN ◽  
Ying WANG ◽  
Jinli Li ◽  
Haibo Hu ◽  
...  
Keyword(s):  
Nitrogen Dioxide ◽  
Human Health ◽  
Room Temperature ◽  
Gas Sensing ◽  
Air Pollutant

Nitrogen dioxide (NO2) is a prominent air pollutant that is harmful to both the environment and human health. Conventional NO2 sensors that are designed to operate at room temperature often...

scholarly journals Influence of Alumina Precursor Properties on Cu-Fe Alumina Supported Catalysts for Total Toluene Oxidation as a Model Volatile Organic Air Pollutant

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 252
Author(s):  
Tadej Žumbar ◽  
Alenka Ristić ◽  
Goran Dražić ◽  
Hristina Lazarova ◽  
Janez Volavšek ◽  
...  
Keyword(s):  
Surface Characterization ◽  
Iron Concentration ◽  
Catalytic Performance ◽  
Air Pollutant ◽  
Molar Ratio ◽  
Homogeneous Distribution ◽  
Total Oxidation ◽  
Alumina Support ◽  
Determining Factors ◽  
Volatile Organic

The structure–property relationship of catalytic supports for the deposition of redox-active transition metals is of great importance for improving the catalytic efficiency and reusability of the catalysts. In this work, the role of alumina support precursors of Cu-Fe/Al2O3 catalysts used for the total oxidation of toluene as a model volatile organic air pollutant is elucidated. Surface characterization of the catalysts revealed that the surface area, pore volume and acid site concentration of the alumina supports are important but not the determining factors for the catalytic activity of the studied catalysts for this type of reaction. The determining factors are the structural order of the support precursor, the homogeneous distribution of the catalytic sites and reducibility, which were elucidated by XRD, NMR, TEM and temperature programed reduction (TPR). Cu–Fe/Al2O3 prepared from bayerite and pseudoboehmite as highly ordered precursors showed better catalytic performance compared to Cu-Fe/Al2O3 derived from the amorphous alumina precursor and dawsonite. Homogeneous distribution of FexOy and CuOx with defined Cu/Fe molar ratio on the Al2O3 support is required for the efficient catalytic performance of the material. The study showed a beneficial effect of low iron concentration introduced into the alumina precursor during the alumina support synthesis procedure, which resulted in a homogeneous metal oxide distribution on the support.

scholarly journals The Improvement of Indoor Air Quality in Residential Buildings in Dubai, UAE

Buildings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 250
Author(s):  
Chuloh Jung ◽  
Jihad Awad
Keyword(s):  
Computer Simulation ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Building Materials ◽  
Field Survey ◽  
Residential Buildings ◽  
Radon Gas ◽  
Volatile Organic ◽  
Residential Projects

Due to unprecedented urbanization, UAE had built many new residential projects with poor choices of material and ventilation. This social phenomenon is leading UAE to Sick Building Syndrome (SBS) faster than any other countries. The Dubai Municipality regulates the indoor air quality with strict stipulation, but the detailed regulations are still insufficient. The objective of this paper is to measure the indoor air quality of new residential projects in Dubai to suggest the improvement of the regulations for indoor air quality. As a methodology, a field survey was conducted to investigate the status of indoor air pollution in residential buildings. Based on the field survey data, lab experiments for building materials were conducted and a computer simulation on radon gas was conducted. The result had shown that radon gas was mainly detected in new townhouses and labor camp houses, and its concentration was found to exceed the standard. Volatile organic solvents (VOCs) and formaldehyde (CH2O) were mainly detected in showhouses and new townhouses, and the concentration distribution was about 10 times higher than that of outdoors. It was proven that emission concentration of radon gas from various building materials were detected, and the order was red clay, gypsum board, and concrete. Volatile organic solvents (VOCs) are mainly detected in oil paints and PVC floor and the radiation amount of all pollutants increased with temperature increase. In computer simulation, it was found that a new townhouse needs a grace period from 20 days to 6 months to lower the radon gas concentration by 2 pCi/L. This study will serve as a basic data to establish more detailed regulation for the building materials and improve the IAQ standards in Dubai.

Sign in / Sign up

Export Citation Format

Share Document