Papers by Keyword: Volatile Organic Compound (VOC)

Abstract: The influence of hot-pressing parameters on formaldehyde and other volatile organic compounds (VOC) were studied in this paper. The particleboard of larix gmelinii and UF resin were used as main raw materials. Orthogonal design was adopted to analyze the influence of hot-pressing temperature, time, resin and density on the concentration of formaldehyde and other VOC. The results showed that the emission of formaldehyde and other VOC were significantly affected by hot-pressing temperature, time, resin and density. The emission of formaldehyde and other VOC were obviously decreased in usage with the increasing of hot-pressing temperature, press time and the decreasing of density. Taking formaldehyde and other VOC emission into account, the optimized condition was hot-pressing temperature of 180°C, press time of 5 min, resin content of 11%, board density of 0.6g/cm³. The emissions of optimized particleboard satisfied the national standard GB18580-2001.

Abstract: A chemical gas sensor for volatile organic compounds (VOCs) detection at trace level is proposed. In this paper, the development and demonstration of the sensor prototype are presented. The prototype is based on a microcantilever resonator that is fabricated from direct bonding silicon-on-insulator (SOI) wafer. The resonant cantilever employs integrated thermal driving and piezoresistive detecting units, and operates in a self-oscillation system. Polyethylenevinylacetate (PEVA) is deposited on top of the cantilever as gas sensitive layer through a spraying method. The responses of the prototype to relative humidity (RH) and six common VOCs: toluene, benzene, ethanol, acetone, hexane and octane have been tested. The PEVA-coated prototype has trace sensitivity to toluene, benzene, hexane and octane, while is insensitive to humidity. The experimental results provide confirmation that the microcantilever resonator is an excellent platform for chemical gas sensor.

Abstract: A pilot-scale experimental system of filling gasoline into a tank was built to investigate gasoline vapor-air mass transfer in the tank gas space and the vapor evaporation loss from the tank in different operating conditions. The results showed that the higher the location of filling pipe exit inside the tank, the quicker the speed of the filling gasoline, and the higher the initial vapor concentration in the tank gas space, then the more severe the vapor-air convective transport and the larger the gasoline evaporation loss rates.

Abstract: Volatile organic compounds (VOCs) gas sensor based on gated lateral bipolar junction transistor (LBJT) was developed in this study. The device was fabricated using 0.35-μm logic process by Magnachip-Hynix Co. Ltd. under the Integrated Circuit Design education Center Multi Project Wafer (IDEC-MPW) program. Solvatochromic dye as the sensing membrane was coated on the floating gate of the device. A semiconductor test and analyzer (STA-EL421, ELECS) was used to measure the sensing results. Following the results, we found that the sensing device which used the gated LBJT device has fast responsibility and reversibility to VOC gases (acetone etc.).

Abstract: Hierarchical SnO2 (H-SnO2) and particulate SnO2 (P-SnO2) nanostructures were synthesized by a hydrothermal method with and without the aid of sodium 1-dodecanesulfonate (SDS), respectively. X-ray diffraction and scanning electron microscopy were used to characterize the products obtained. The sensing properties of the H-SnO2 and P-SnO2 nanostructures to volatile organic compound gas (VOCs) were measured. The H-SnO2 sensors show better gas-sensing performance than the P-SnO2 sensors due to the hierarchical microstructure.

Abstract: The purpose of this study is to reveal the concentration variations of VOC concentrations of larch particleboards with different processing parameters. The mat moisture content (MC), panel type and density were chosen as the influencing factors to investigate the VOC emissions after processing, and consequently provide basic guideline for the selection of processing parameters of particleboards to control the pollutants. 1m³ environmental chamber and portable VOC monitor were used for VOC sampling and analysis. The results showed that these factors had significant impact on VOC concentrations. The increase of MC, board panel and density had a positive effect on VOC emissions. With the MC and board density various in the ranges from 6%-14% and 0.60-0.80 g·cm^-3, the TVOC concentrations increased 42.6% and 74.7% separately. The three layers particleboard had the higher concentration than the single layer particleboard.

Abstract: In order to comprehensive understand and control volatile organic compounds (VOCs) release from particleboards, this paper takes Larix gmelini particleboard as example and analyzes VOCs by three different methods. First of all, VOCs of Larix gmelini particles were detected by the static head space solid-phase micro-extraction (HS-SPME) technique. Secondly Larix gmelini particleboards were analyzed using the method of adsorbed by activated carbon, desorpted with methylene dichloride and measured by GC/MS. Finally, Tenax-T Thermal desorption -GC/MS was used to qualitative VOCs emissions. The best method for determination VOCs from particleboards was found. SPME is a simple operation method with short time. But the pretreatment of sample was troublesome and it is not easily measured for lower concentration particleboards. Active carbon absorption method is not suitable for quantitative because of much error in extraction. It is suitable for qualitative analysis. Tenax-T is a simple operation way with short analysis time and good shape of chromatographic. It is a convenient and practical method. Further study of VOCs emission of panels can be supported by this method.

Abstract: Smoked bamboo, which was made by bamboo in high temperature smoke, is a new indoors materials. In order to evaluate its potential health risk to human settlements, the volatile organic compounds of smoked bamboo biomaterial were adsorbed and determined by TD-GC-MS. And the main constituents of volatiles at 60°С were cyclononasiloxane, octadecamethyl-(35.14%), acetic acid(23.27%), cyclotrisiloxane, hexamethyl- (9.53%), bicyclo[4.4.0]dec-1-ene,2-isoprop yl-5-methyl-9-methylene-(7.56%), silane, 1,4-phenylenebis[trimethyl(4.32%), 1,3-benzodioxole, 5-(2-propenyl)- (3.47%), cedrol(2.75%), etc. (2) The main constituents of volatiles at 130°С were acetic acid(43.78%), 2,5-furandione, dihydro-3- methylene-(16.57%), 1,3-benzodioxole, 5-(1-propenyl)-,(z)-(6.75%), octasiloxane, 1,1,3,3,5,5,7,7,9,9, 11,11,13, 13,15,15- hexadecamethyl -(4.09%), bicyclo[2.2.1]heptan-2-one, 1,7,7- trimethyl-, (1s)- (3.21%), etc. Generally, the smoked bamboo biomaterial was safe under 60-130°С.

Abstract: A fast testing procedure for the determination of VOCs in textile matrix using solid phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) was introduced. Samples were cut into small pieces and soaked in 5% methanol (v/v) saturated NaCl solution with supersonic pretreatment at 40±1°Cwater-bathing for 15 min and headspace exposure for 10 min at 50°C with stirring rate at 1100rmp. The influence of SPME adsorption time, stir speed, adsorption time and temperature, and gas chromatography (GC) inlet conditions for the SPME were investigated. Then the matrix solutions were extracted by headspace SPME and analysis by GC/MS. Under the optimized conditions, the limits of detection for target compounds were 0.005mg/kg with average recovery between 90.6-108.7%. The results obtained clearly showed the potential of SPME for efficient concentration of the target compounds and also demonstrated the reliability of this extraction technique for the monitoring of textile quality for the eco-marks.

Abstract: Based on the photo ionization principle, a gas sensor for the hydrazine is designed. The photo ionization gas sensor can also measure other volatile organic compounds and other gases in concentrations from sub parts per billion to 10000 parts per million (ppm). This gas sensor is the most efficient and inexpensive type of gas sensor. They are capable of giving real-time readings and monitoring continuously. The design of micro ionization chamber, signal detection circuits and installation technology is expatiated in detail. Through researching the design of cell structure, the cell with integration and miniaturization has been devised. By taking Single-Chip Microcomputer (SCM) as intelligence handling, the functional block diagram of gas detection system is designed with the analyzing and devising of its hardware and software system. Experiment results show that the gas sensor has reached the technology requirement of portable, mini-volume, high accuracy, fast response, continuous test, and is able to apply in detecting the organic gases. Therefore, the photo ionization sensor has a promising future for the hydrazines gas and volatile organic compounds detection.