Papers by Keyword: VOC

Abstract: In order to investigate the characteristic of volatile organic compounds (VOCs) from wastewater treatment plant (WWTP), the air and water samples were collected. The air samples were extracted and identified by GC/MS. The atmospheric VOCs species from all WWTP units were tested. It was shown that the main fugitive sources were primary clarifier and the room of sludge dewatering. The numbers were 33 and 30. The total species of VOCs emitted varied with a range of 16 to 33. The relationship between VOCs species and the change of water quality were discussed. The increasing of VOCs species was related with the higher SUVA, and the molecular weight of VOCs species in air sample gradually become lower along the wastewater treatment process. In the wastewater treatment process，the function of microbe did not contribute the whole effort on the removing of organic pollutants. VOCs volatilized from water phase could also reduce organic pollutants in water phase. In the whole WWTP, the main VOCs species were alkyl with small molecular weight, aromatic hydrocarbon material and naphthalene. Halogenated hydrocarbon was detected in primary treatment unit and anoxic tank.

Abstract: Microporous silica material AMPS has been synthesized via TEA+ cations assisted self-assembly of silica species in acidic aqueous solution. Nitrogen adsorption analysis revealed 0.65 nm uniform micropores in AMPS, companied with a Langmuir surface area of 745 m2/g and a pore volume of 0.22 cm3/g. The microporous AMPS exhibited an excellent adsorptive performance for volatile organic compounds (VOC) such as cyclohexane and acetone, compared with conventional zeolites such as Y, ZSM-5 and A. The adsorption was rapidly saturated at lower relative pressure with higher capacities than that of conventional zeolites. These features implied promising potentials in the separation and removal of VOCs in the atmosphere by using APS-3.

Abstract: Particleboard has been indicated as one possible source of volatile organic compounds (VOCs) at normal indoor. This paper examines the VOCs emissions from the larch particleboards. Temperature, relative humidity and air change rate are significant factors influencing the VOCs emissions from particleboards. With the temperature and humidity various in the ranges from 23°C-40°C and 10%-70%RH the TVOC concentrations increased. Whereas the increasing of air change rate causes the TVOC concentration decreased.

Abstract: The removal efficiencies of 4 air-cleaning materials on formaldehyde and VOC emissions from particleboards were examined in this paper. The effect of activated carbon and photo catalyst on formaldehyde and VOC emissions removal was notable in short time. The effect of scavenger was obviously on formaldehyde removal for its synthetic mechanism. And the impact of bioenzyme on formaldehyde and VOC emissions from particleboards is dependent on the test conditions and it shows no impact on emissions in this experiment.

Abstract: The aim of this paper is to study on how to control VOC emissions from wood-based panel manufacturing. Total volatile organic compounds (TVOC) emissions from larch particleboard under different processing conditions were collected by an environmental chamber. VOC samples were prepared by desiccator, adsorbed by activated carbon, desorpted with Methylene dichloride and measured by GC/MS. The result showed that the optimal process parameters were single-layer structure, moisture content of 6%, density of 0.60 g•cm-3, thickness of 8mm, resin content of 7%, hot-pressing time of 4min.TVOC increased with board density going up，hot-pressing time increasing, moisture content and resin content rising. The predominant compounds emissions from the particleboards are aromatic compound and hydrocarbon. 24 kinds of compounds were identified from the standard board. With hydrocarbon decreasing, aromatic VOC type increased.

Abstract: The configuration of discharge electrode is closely related to the uniformity and the strength of corona plasma, which has big effect on the efficiency of plasma in destructing pollutants, treating materials and so on. A novel sheet electrode was devised to enhance the input energy and the uniformity of plasma’s distribution, and its production performance of plasma was compared with other discharge electrodes including wire, needle and multi-needles. Corona images and I-V characteristic curves of discharge electrodes indicate that ultra-thin sheet electrode could produce more uniform and stronger corona plasma zone than other electrodes in this paper, which is advantageous for decomposing pollutants, treating material surface and so on. Primary VOCs decomposition experiments were conducted, and the results indicated that the highest energy yield of VOCs decomposition reached 1.8 g (benzene) • (kWh)-1 /3.5 g (toluene) • (kWh)-1.

Abstract: The p-NiO/n-ZnO transparent pn heterojunction is prepared by RF magnetron sputtering technique and processed into a chemical sensor element by photolithography pattering and chemical etching process. Forward biased p-NiO/n-ZnO heterojunction sensor can detect VOCs at room temperature and its gas sensitivity is extremely enhanced with the assist of deep UV light incidence. Even if the testing gas is thermodynamically stable such as aromatic VOC, the p-NiO/n-ZnO heterojunction sensor can detect it with the concert mechanism involving “electric” and “photo” assistance.

Abstract: A microwave/Fe3O4 catalytic system was proposed for treatment of volatile organic carbons (VOCs). This system comprises a household microwave oven modified as the reaction chamber, which was fitted with a vertical, cylindrical quartz reactor comprising a catalytic packed column filled with granular Fe3O4, a microwave catalyst of iron (II, III) oxide. Experimental results showed that the destruction and removal efficiency (DRE) of toluene by microwave alone was close to zero, but with the microwave/Fe3O4 system, the temperature of the catalytic packed column increased rapidly and reached thermal balance within 10-15 min. Analysis of the rear gas after combustion showed that most of the toluene was thermal oxidized into CO2 and H2O. The successful application of the proposed microwave/Fe3O4 system to thermal destruction of toluene promises a new technology for treatment of VOCs.

Abstract: 1) Upon comparing Ceramic products, which have been made into samples by the exactly same construction method as prefabbed wall of apartment, with the existing products, it is revealed that there would beno diminution effect on Pollutants like TVOC and HCHO. On the contrary, from the Ceramic applied prefab-wall, some pollutants, which were not seen from normal wall-panel, had been emitted additionally. 2) When we spreaded seven kinds of catalyst products on the surface of samples of MDF furniture and tested, two of those applied samples showed stronger tendency regarding the TVOC and HCHO emission than unapplied samples. Consequently, it is clarified that there's no effect of eliminating the pollutants like TVOC and HCHO from the application of catalysts as well as ceramic. In this regard, when we consider all the results collectively which were earned from these analysises up to now, using indiscreet after-treatment materials in residential place should be applied only after prudent examination.

Abstract: Inorganic frameworks obtained by the sol-gel route can be templated by a molecular imprinting (MIP) approach to generate functional cavities. Such MIP ceramics show highly appreaciable properties for chemical sensor applications, because they are inherently chemically and thermally robust. In combination with mass-sensitive devices (e.g. quartz crystal micro balance – QCM, surface transverse wave oscillator - STW), they yield highly selective and sensitive chemical sensors. Gas phase measurements with volatile organic compounds (VOCs) e.g. lead to sensitivities below 1 ppm. Sensitivity can be tuned by the sol-gel-precursor: when hydrolysing more bulky alkoxides, this leads to enhanced sensitivity by increasing porosity as a consequence of slower solvent evaporation. By adding products of oxidative oil degradation to the sol-gel mixture, we succeeded in generating sensors for degradation processes in these complex matrices. This allows parallelly monitoring both the chemical state of oil and changes in viscosity. Sensitivity is enhanced according to the Sauerbrey equation by going from 10 MHz QCM transducers to higher frequencies either by etching the quartz substrates and so reducing the resonator thickness or by applying STWs.