Papers by Keyword: VOC

Abstract: In order to successfully reduce the emission of toxic organic solvents harmful to human health and the environment during the application and curing of paints and varnishes (VPM), ways to create environmentally friendly organically soluble VPM "SB" and water-dispersed VPM "WB" are proposed. The influence of the values of dry residues in solutions of organic oligomers and the density of the components of pigmented materials on the values of the content of volatile organic compounds (VOC) for different types of materials has been studied. Mathematical analysis of situations with the addition and reduction of the amount of solvents allowed to set the limit values of the amount of solvents in varnishes for "SB" materials with different densities and VOC = 300 g/l. The influence of volumetric concentration of pigments, dry residue of varnishes and density of pigments and fillers on the VOC content in materials has been studied. The ratios of VPM components have been optimized and formulations of environmentally friendly materials have been developed.

Abstract: The aim of this work is to investigate chemo-resistivity properties of natural rubber-carbon nanostructure composite, that’s why a change of diffusion characteristics and reversibility of electro-chemical properties of the composite with different degree values of crosslinks have been analysed. The composites are made from natural rubber (polyisoprene) as matrix material and high structure carbon black as electro-conductive filler. In order to investigate diffusion characteristics of volatile organic compounds (VOC) in relation to chemo-resistive response of composites simultaneous mass, length and electrical resistance change measurements of the samples, when samples are held in VOC and after exposures to VOC were carried out. Electrical resistance increase mechanism in the composite advances with the composite structure development during vulcanization.

Abstract: Graphene-Tin Oxide (G-SnO₂) nanocomposites in different morphology were synthesized using tin (II) chloride (SnCl₂) and graphene Oxide (GO) via hydrothermal process in the presence of hydrazine and ammonia by adding surfactant for 12 hours in a teflon autoclave at 100oC reaction temperature. Poly (vinyl prolidon) (PVP) and poly (ethylene glycol) (PEG) were used as nonionic surfactants while hexadecyl trimethyl ammonium bromide (CTAB) and sodium dodecyl sulfonate (SDS) were utilized as cationic and anionic surfactants, respectively. The synthesized nanocomposites were characterized by XRD, FESEM, C-TEM and FT-IR. The gas sensing properties of the obtained samples to the vapors of various Volatile Organic Compounds (VOC), such as Ethanol, Methanol, Chloroform, Toluene and Acetone were also investigated at room temperature. The prepared G-SnO₂ nanocomposites exhibited high detection performances for ethanol, chloroform and methanol. The nanocomposites could be used as sensor material for VOC gases.

Abstract: Vehicles are the dominant source of many air pollutant emissions in urban areas. The effects caused by vehicle emissions have been receiving increasing attention, and recent epidemiological studies show elevated risks of cardiovascular morbidity, cancer, allergic diseases for drivers, commuters and individuals living near roadways. During the experimental research conducted in this paper, emission characteristics of Otto 1.1 EFI engine were investigated in varying operating modes in order to adequately simulate the movement of the Fiat Punto Classic (FPC) passenger car in city driving conditions in line with the New European Driving Cycle (NEDC). The NEDC is a stylized cycle, with periods of constant acceleration, deceleration and constant speed, and it is supposed to represent the typical usage of a passenger car in Europe. The analysis of exhaust gas samples was conducted by using the gas chromatography technique in combination with the photoionization detector (GC/PID). The results of emission tests indicate high concentration levels of toluene in the exhaust gas mixtures, ranging from 7.07 to 116.87 ppm. The total mass of the emitted toluene after 100 km of driving in accordance with the NEDC was 7.7647 g.

Abstract: A waterborne anticorrosive coatings was prepared with homemade organic silicone 3-(trimethoxysilyl) propyl methacrylate modified epoxy acrylate emulsion as basic material, glass flake as anticorrosive filter and titanium dioxide as pigment and other additives. The anti-acid alkali salt, AC impedance, polarization curve tests were done to evaluate the coatings’ anticorrosion properties and to optimal its formula and process. The results showed that the best formula was: glass flake 35%, particle size 80 meshes, titanium dioxide as anticorrosive pigment 18% and the emulsion with epoxy at 45% content as base material. In this case, the coatings’ anti-acid, alkali and salt’s properties is good, the impedance values was up to eight orders of magnitude, the corrosion current was 9.59 × 10^-8A and every indicator met the requirements of the JB/T224-2007 "Building with Steel Structure Anticorrosion Coatings". The water-epoxy anti-corrosion coating has safe environmental protection, zero VOC, excellent anti-corrosion properties and other indexes meet national standards.

Abstract: Volatile organic compounds (VOC) emission from different asphalts not only causes the change in the performances of the bitumen, but also its chemical compositions. This paper carried out four-component analysis to study the influence of VOC emission from different asphalts on bitumens chemical compositions under different conditions. Results show that four-component of asphalts from different places is different. Also as the time of VOC emission increases, the total contents of resins and asphaltenes increase, but the total contents of saturates and aromatics decrease. VOC emission under different temperatures also has a great impact on the asphalt chemical components; Saturates and aromatics decrease in high temperature is larger than in low temperature, and there exists big differences in the asphalt surface layer and the internal of chemical components.

Abstract: Light components in the asphalt can volatilize under the circumstances of high temperature or long-term service process, leading to the deteriorating of the asphalt pavement. This paper tried to discuss the influences of volatile organic compounds (VOC) emission from the asphalt on physical properties in the high temperature (at 180) by grey system theory. Both Heat and Vacuum environment were monitored as the emission conditions and the emission temperature was 180°C, physical properties of asphalt, released and unreleased were analyzed. Basic tests, including mass change, chemical compositions, penetration and soften point, were used to compare the influences of VOC emission on the asphalts performances. Meanwhile, grey system theory was used to investigate the sequent performances influenced by VOC emission. Results show that physical properties and four generic components of the asphalts are affected obviously in these two emission conditions, and the oxygen may promote VOC emission from the asphalt. In additional, the greatest factor associating with VOC emission is light components in the asphalt.

Abstract: The emission of volatile organic compounds (VOC) from single-component polyurethane varnish applied to beech plywood at two temperatures (33°C, 43°C) has been investigated in a small environmental chamber. The experimental results indicated that the concentration of each compound, as well as the total volatile organic compounds (TVOC), increased rapidly after the start of experiment, and attained their maximum values at 0.5 h. The concentrations decreased rapidly after 0.5 h, and then decreased more slowly in the period 2 – 24 h. The concentrations of isopropylbenzene, n-decane and TVOC were higher in the 43°C test than in the 33°C test within the first 1.5 h. The influences of temperature on the concentrations of these pollutants were different during the period 1.5 – 24 h.

Abstract: In order to evaluate volatile organic compounds (VOC) from asphalt, this paper explored to use ultraviolet and visible spectroscopy (UV-VIS) as the detection method of VOC. 288nm wavelength was selected as the characteristic absorption wavelength of VOC, finding that VOC quality and its absorbance value showed a good linear relationship which could be the basis for evaluation in this research. Experiments were carried out under different conditions, results of which showed that VOC emission was related to temperatures and asphalt specimens. Moreover, VOC emission increased with increasing temperatures. Results under non-high temperatures conditions showed that VOC emission during its service process should not be ignored.

Abstract: The porous materials are usually the sources or sinks of indoor volatile organic compounds (VOC). In order to predict the VOC emission rate and choose best adsorbents, reasonable estimation of the diffusion coefficients of porous materials is required. Porous materials were usually depicted as a random network of interconnected pores of unspecified sizes and shapes. It may generate deviation to assume the network as simple topological structures. This paper investigated the diffusion coefficients of porous mate­­rials with the fractal theory and derived their diffusion coefficients considering the pore size distribution of the materials. The calculated result was validated by published experimental data.