Amount Of Volatile Organic Compounds Research Articles

Qualifying and Quantifying the Emissions of Volatile Organic Compounds from the Coking Process in a Steel Plant Using an Innovative Sampling Technique

The aim of this paper is to quantify the amounts of volatile organic compounds (VOCs) emitted from a coke oven in a steel plant in Taiwan and estimate the emission factors of VOCs using an innovative sampling technique. The identification of VOCs emissions was referred to in the AP-42 report issued by the USEPA and the field measurement data of fugitive emissions. VOCs were sampled using a self-designed closed sampling system. A total of six emission points, including quenching emissions, charge lid emissions, combustion stack emissions, door emissions, charging emissions, and coke pushing emissions, were identified in the coking process after comparing with the report of AP-42, and the emission factor of VOCs was 0.030 kg/ton-coke. It showed that the emission factor of VOCs via field measurement was approximately 56% of that reported by Taiwan EPA. Therefore, VOCs emissions estimated by the Taiwan EPA would be highly overestimated than those from the coke oven in the site.

Analysis of the absorption kinetics following dermal exposure to large doses of volatile organic compounds

A mathematical method was developed to study the skin penetration of volatile organic compounds (VOCs) after exposure to a high dose of the substance. While closed-form solutions exist to describe the diffusion and evaporation from small amounts, numerical approaches are often implemented to predict dermal transport involving large doses. This work offers a Laplace transform-based method to estimate the time constant and dynamic and steady-state behaviors. First, the process was divided into two stages, separated by the time it took for excess chemicals to be depleted from the skin surface. Series solutions were written for the percutaneous VOC concentration, absorption and evaporation in the first stage. Application of Laplace transform methods yielded transient profiles after the compound dissipated from the surface of the stratum corneum. In addition, the procedure facilitated the calculation of the time constant and steady-state values. The method was validated using benchtop and fume hood experiments conducted with N,N-diethyl-3-methylbenzamide (DEET) and air velocities of 0.165 m/s and 0.72 m/s, respectively. The increase in the flow rate decreased the total amount of VOC absorbed and reduced the period required for the surface fluid to disappear.

Synergistic effects of Al/Si double oxide on flame-retardant and smoke-suppressant wooden materials

Wooden materials have many advantages, but they easily burn and release CO, CO2, and harmful volatile organic compounds (VOCs), which pose threats to health and safety. This work adopted a low-cost method, using environmentally friendly silicate (Na2SiO3), aluminum sulfate (Al2(SO4)3), and water-borne epoxy resin to prepare composite poplar wood (Al–Si-EPW), which synergistic displayed flame retardancy, smoke suppression, and self-extinguishing characteristics. The time of peak heat release rate (HRR) and peak smoke production rate (SPR) of Al–Si-EPWwere 340 s and 315 s, which were delayed by about 105 s and 100 s compared with untreated wood (UW), respectively. This provides more security for controlling the fire spread and evacuating people. The peak value of heat release rate and smoke production of Al–Si-EPW decreased by 39.04% and 34.68%, and the peak CO2 production (CO2P) and CO production (COP) were reduced by 69.75% and 74.74%. Moreover, the main category and the amount of VOCs released during the combustion process decreased significantly. With the increase in aluminum sulfate dosage, it showed better flame retardant and smoke suppression effects. This indicated that Al–Si-EPW only released a small amount of toxic smoke, greatly reducing the possibility of suffocation and damage. Therefore, this material can be widely used as a flame-retardant wood building material.

Noble-Nanoparticle-Decorated Ti3C2T x MXenes for Highly Sensitive Volatile Organic Compound Detection.

Two-dimensional transition-metal carbides and nitrides (MXenes) have been regarded as promising sensing materials because of their high surface-to-volume ratios and outstanding electronic, optical, and mechanical properties with versatile transition-metal and surface chemistries. However, weak gas-molecule adsorption of MXenes poses a serious limitation to their sensitivity and selectivity, particularly for trace amounts of volatile organic compounds (VOCs) at room temperature. To deal with these issues, Au-decorated MXenes are synthesized by a facile solution mixing method for room-temperature sensing of a wide variety of oxygen-based and hydrocarbon-based VOCs. Dynamic sensing experiments reveal that optimal decoration of Au nanoparticles (NPs) on Ti3C2Tx MXene significantly elevates the response and selectivity of the flexible sensors, especially in detecting formaldehyde. Au–Ti3C2Tx gas sensors exhibited an extremely low limit of detection of 92 ppb for formaldehyde at room temperature. Au–Ti3C2Tx provides reliable gas response, low noise level, ultrahigh signal-to-noise ratio, high selectivity, as well as parts per billion level of formaldehyde detection. The prominent mechanism for Au–Ti3C2Tx in sensing formaldehyde is elucidated theoretically from density functional theory simulations. The results presented here strongly suggest that decorating noble-metal NPs on MXenes is a feasible strategy for the development of next-generation ultrasensitive sensors for Internet of Things.

Study of Chemical Substances Emitted during Paint Manufacturing through VOC Speciation

Volatile organic compounds (VOCs) emitted from the paint manufacturing industry include substances that are highly volatile, such as toluene, and highly carcinogenic, such as benzene. In the Republic of Korea, the emission of volatile organic compounds is regulated under the Clean Air Conservation Act, but it is found that individual substances are systematically insufficient. Although the Pollutant Release and Transfer Register (PRTR) is maintained to report the expected emissions from each plant every year, actual measurements are not performed. This study measured and analyzed VOCs at the site fenceline boundary. The ratio of PRTR and VOCs speciation results for xylene and toluene was similar to that of xylene 29% and toluene 28%, but ethylbenzene accounted for 2% in PRTR. Still, the actual measurement result showed a big difference of 11%. Because it is a solvent that is treated in large quantities in the resin manufacturing process and the reactivity of ethylbenzene, it is vaporized at high temperature and high pressure, resulting in many measurements. This study classified a large amount of VOCs emitted through the fence line monitoring system in the paint manufacturing industry and confirmed which VOCs were emitted the most. We compared whether this produced similar results to the actual emission survey method conducted by the EPA. Some substances have produced similar results, but certain substances have significant differences. This indicates that priority VOCs should be selected for each location through continuous measurement.

Emission of volatile organic compounds from heat-treated Scots pine wood as affected by wood drying method: Results obtained with olfactory machine and headspace gas chromatography-mass spectrometry

Due to the use of heat-treated wood products like ThermoWood®, even for indoor applications, the type and amount of volatile organic compounds (VOCs) emitted from the products are essential for indoor air quality and human health. The drying method of wood applied as the first step in the ThermoWood® production process may influence this property. In this study, the effects of radiofrequency/vacuum (RF/V) drying technology in comparison with conventional kiln drying at a mild and normal temperature on the emission of VOCs from Scots pine ThermoWood® were investigated using Headspace Gas Chromatography-Mass spectrometry (HS-GC-MS) and olfactory system (electronic nose). An olfactory machine consisting of 6 metal oxide semiconductors (MOS) sensors were used for this purpose. Principal Component Analysis (PCA) and Linear Discriminant Analysis (LDA) were applied to classify and analyze the data of olfactory signals. Results showed that emission of VOCs was higher in the samples dried by RF/V technology and was mainly consisted of terpenes, aldehydes, and alcohols. Acids were identified as the main VOCs in the ThermoWood® produced from RF/V dried wood. The emission of some VOCs, such as terpenes, was reduced after thermal modification. Overall, it can be concluded that the type and the amount of VOCs of ThermoWood® are influenced by the drying method of wood applied before starting the thermal modification.

Highly transparent castor oil‐derived polyurethane/silica nanocomposite coating synthesized by in situ polymerization

AbstractThe automobile paint industry normally consumes petro‐based feedstock as the raw material, which is non‐renewable and emits a higher amount of volatile organic compound, that pollutes the environment. This study focuses on the use of eco‐friendly castor oil (CO) as a substitute for petro‐based feedstocks; while synthesizing polyurethane (PU)‐based automobile clear coats. An acrylate‐PU/nano‐silica (NS) hybrid coating was developed, which was derived from CO‐based polyol. CO was modified by employing a process that includes epoxidation, followed by transesterification, and acrylation to synthesize the required polyols, which is used for acrylate‐PU paint synthesis via the in‐situ polymerization process. Triallyl isocyanurate (TI) modified NS particles were incorporated with the paint matrix by the ultrasonication method to enhance the paint properties. Experimental findings revealed that with the incorporation of NS particles, char residue, Young's modulus, abrasion resistance, and cross‐cut adhesion % increased by 71.31%, 42%, 0.28%, and 5% respectively. Also, glass transition temperature, pencil hardness, nanoindentation depth, water contact angle, and cross‐linking density were increased from −12.16°C, 2H, 3300 nm, 81.71°, and 0.90 mol/m3 to 1.65°C, 3H, 2000 nm, 92.26°, and 1.78 mol/m3 respectively. The UV‐visibility spectra, haze, transmittance, and gloss parameter showed the enhanced optical properties of the paint samples. PU/NS composite coating developed showed equivalent properties as that of the commercial clear coat.

Micro and Nano Fiber Composite Coatings

Abstract: Environmental friendly products are becoming popular and acceptable in industries due to the global limitation to the amount of volatile organic compounds (VOCs) released into the atmosphere. Low VOC compounds and technologies are also becoming a choice in the coatings and paint industry. Coatings can be made from water or solvent. In coatings from water, we use water as the solvent, therefore coating called water based coating and in the case of solvent-borne coatings, we used organic or inorganic compounds as solvents, therefore this coating called as solvent borne coating. Among all different types of solvents water is the greatest choice among these low VOC technologies for usage as a solvent to manufacture chemical compounds and Paints and coatings. because water is often recognized as a low-cost, safe, non-toxic, easily available and ecologically friendly solvent. Also nanomaterials is new field in research and development of material science . Materials can be one dimensional such as small particles, materials can be two dimensional such as fibres. Therefore in two-dimensional materials such as fibres ( micro and nanofibers) use in many different applications such as medical, composites, aerospace, Building constructions etc. Nanofiber has the advantage of high surface area to volume ratio hence to decrease the coating defects. micro and nanofibers should be incorporated inside the coating matrix. This way one can improve the properties of water-based coatings. Hence low VOC solvent water with high surface area fibre is becoming a trend in composite coating and nanotechnology in fibres. This review provides information on Composite coatings, distinct fibres used in coatings and their applications, also effects of different aspect ratio of fibres on properties of coatings

Design of volatile organic compounds profiles of roasted Coffea arabica extracts produced by supercritical and conventional solvents

SummaryThis work addresses the potential of supercritical fluid extraction (SFE) to design volatile organic compounds (VOCs) profiles using roasted Coffea arabica. On the whole, 57 VOCs were identified by HS‐SPME/GC–MS. A full factorial design was adopted to study the effect of pressure (180 and 300 bar), temperature (40 and 80 °C) and ethanol content (0 and 5 wt.%). The total extraction yield ranged from 1.4 wt.% to 9.8 wt.%. At 180 bar and 80 °C, two extracts exhibited VOCs amount up to 3.5 times higher than the dichloromethane extract. Temperature and pressure favoured VOCs amount and total yield in conflicting ways, and ethanol had a negligible effect on VOCs amount. At 180 bar and 80 °C, the VOCs profile revealed a reinforcement of pyrroles, phenols, cyclopentenes and pyrans, at the expense of pyridines, carboxylic acids and furans. Hence, this essay evidences the potential of SFE to engineer coffee VOCs profiles.

Spoilage Potential of Contaminating Yeast Species Kluyveromyces marxianus, Pichia kudriavzevii and Torulaspora delbrueckii during Cold Storage of Skyr.

This study investigated the spoilage potential of yeast strains Kluyveromyces marxianus (Km1, Km2 and Km3), Pichia kudriavzevii Pk1 and Torulaspora delbrueckii Td1 grown in skyr in cold storage. Yeast strains were isolated from skyr and identified by sequencing of the 26S rRNA gene. K. marxianus yeasts were grown in skyr to high numbers, generating large amounts of volatile organic compounds (VOC) associated with off-flavours, among them were alcohols (3-methyl-1-butanol, 2-methyl-1-propanol and 1-hexanol), esters (ethyl acetate and 3-methylbutyl acetate) and aldehydes (hexanal, methylbutanal and methylpropanal). Growth of P. kudriavzevii Pk1 led to moderate increases in several alcohols and esters (mostly, 3-methyl-1-butanol and ethyl acetate), whereas only minor shifts in VOCs were associated with T. delbrueckii Td2. The levels of the key aroma compounds, diacetyl and acetoin, were significantly decreased by all K. marxianus strains and P. kudriavzevii Pk1. In contrast to the other yeast species, K. marxianus was able to utilize lactose, producing ethanol and carbon dioxide. Based on the overall results, K. marxianus was characterised by the highest spoilage potential. The study revealed the differences between the yeast species in fermentative and spoilage activities, and clarified the role of yeast metabolites for off-flavour formation and quality defects in skyr during cold storage.

Performance enhancement of bio‐based rubber composites using epoxidized natural rubber for silica without carbon emissions and volatile organic compounds

AbstractTire development tendency is green, environment‐friendly, and safeguarding life and health. The conventional tires, consisting of solution polymerized styrene‐butadiene rubbers (SSBR), silica, silane coupling agents, and other rubber additives, will not be able to keep up with the demand. SSBR, as a synthetic rubber processed from nonrenewable petroleum resources, creates a large amount of carbon emissions in the production process and the reaction between silica and silane coupling agents generates a large amount of volatile organic compounds (VOCs), which is detrimental to the environment and human health. In this article, epoxidized natural rubber (ENR) with different epoxide degrees was successfully prepared and blended with natural rubber (NR)/silica composites to improve the dispersion of silica and the performance of nanocomposites. The effect of heat treatment temperature on the reaction between ENR and silica and the dynamic and static mechanical properties of ENR/NR/silica nanocomposites was investigated by mechanical properties test, transmission electron microscopy, x‐ray photoelectron spectroscopy, and Fourier transform infrared. The results showed that the epoxy groups on the ENR molecular chain could react with the silanol on the surface of silica to form a strong chemical bond, which improved the dispersion of silica in the rubber matrix and further enhanced the performance of the rubber composites without carbon emission and VOCs.

Siloxane-modified MnOx catalyst for oxidation of coal-related o-xylene in presence of water vapor

In coal-combustion energy production, presence of water vapor in flue gas causes catalyst deactivation and leads to the release of large quantities of volatile organic compounds (VOCs). In this study, design of a low-temperature, hydrophobic catalyst for flue gas purification was achieved by modifying support material with inorganic siloxane. Introduction of 5% water vapor into simulated flue gas at 300 °C reduced oxidation efficiency for o-xylene removal by 26% with unmodified MnOx/γ-Al2O3 catalyst, whereas with modified catalyst MnOx-Si0.9/γ-Al2O3 oxidation efficiency was reduced by only 5%. MnOx-Si0.9/γ-Al2O3 exhibited stable catalytic efficiency for o-xylene gas oxidation containing water vapor for over 200 min. Water-resistance of the catalyst was effective for removal of multi-coal combustion pollutants (Hg0 and NO) and moreover, hydrophobicity of the catalyst led to a reduction in surface sulfate deposition, thereby lowering toxicity of SO2 from simulated flue gas. DRIFTS analysis showed that the hydrophobic catalyst surface not only reduces water adsorption, but also promotes water volatilization. Based on molecular adsorption energies, catalyst support modification with siloxane inhibits water adsorption and promotes organic adsorption and thus provides a new strategy for preparing water-resistant catalysts for flue gas purification.

Fire risk problem of aluminum foundry

During various modes of operation of the melting furnace, a large amount of aerosol particles consisting mainly of amorphous carbon is generated irregularly depending on the current state (especially during the loading of the return material), accompanied by the development of significant amounts of volatile organic compounds and methane. The resulting mixture of organic substances is not quantitatively eliminated in the afterburner chamber of the melting furnace. The VOC mass flow remains almost unchanged and only the methane mass flow decreases. The mass flux of aerosol particles, on the other hand, increases after passing through the afterburner chamber, with particles of aluminium metal contributing significantly to this increase. The aerosol particles trapped on the textile filter of the melting furnace are thus composed of particles of amorphous carbon and particles of inorganic origin (metallic aluminium and limestone). The structure and surface properties of the carbon particles pose a significant risk of textile filter ignition. From the measurement results obtained, the following solution to the hazardous condition of the plant can be found: (a) a change in the existing technology, for example: changing the design of the part of the melting furnace into which the return material is fed; changing the heat input and the mode of the gas burner and fan in this part of the furnace; a significant reduction of the flue gas flow in the A-gauge and afterburner chamber or change of machining emulsion; (b) the installation of an additional gas burner in the newly installed afterburner chamber, to which the flue gases from the part of the melting furnace into which the return material is fed would be discharged in the existing return material inlet mode.

High O2/N2 controlled atmosphere accelerates postharvest ripening of ‘Hayward’ kiwifruit

Kiwifruit (Actinidia deliciosa cv. Hayward) was exposed to high O2/N2 controlled atmosphere (30 % O2 + 70 % N2) for 7 d at 23 ± 1 °C to evaluate the effects on postharvest ripening and fruit quality. The treated fruit exhibited a dramatic increase in soluble solids content (SSC) and a rapid decrease in firmness and titratable acidity (TA), accompanied by a noticeable change in flesh color and volatile organic compounds during the first 7 d. Fruit exposed to high oxygen concentration required 7 d to reach the edible firmness (∼ 10 N), while the control fruit needed 42 d. At edible firmness, no differences in the SSC, TA, and flesh color were observed between treated and untreated kiwifruit, although the concentration and amounts of volatile organic compounds showed a little difference. High O2/N2 controlled atmosphere advanced respiration rate peak, with an increase in the contents of adenosine triphosphate (ATP), adenosine diphosphate (ADP), and adenosine monophosphate (AMP). The treatment also increased catalase (CAT) and peroxidase (POD) activities. Quantitative real-time PCR revealed increased expression levels of AdAAC1, AdAOX2, AcEXP1, AcPL1, AcPG, AcACS, AcACO, and AcACO2 in the treated fruit. Thus, the study's results indicate that high O2/N2 controlled atmosphere could accelerate kiwifruit ripening and result in good fruit quality.

Ozone Treatment Increases the Release of VOC from Barley, Which Modifies Seed Germination.

Ozone is widely used to control pests in grain and has an impact on seed germination. The germination process involves multiple secondary metabolites, such as volatile organic compounds (VOCs), which are altered under ozone treatment. Here, an optimized solid-phase microextraction coupled with gas chromatography-mass spectrometry was implemented to explore changes in VOCs from barley seeds under ozone treatment. The data demonstrated that barley released both a greater variety and quantity of VOCs under oxidative stress. The number of alcohols and hydrocarbons gradually decreased, whereas aldehydes and organic acids markedly increased with increasing ozone treatment time. Acetic acid was identified as a potential ozone stress-specific marker. Furthermore, the dosage-dependent function of acetic acid on the germination of barley was verified, namely, a low dosage of acetic acid increased the germination and vice versa. This study provided new insights into how barley responds to ozone treatment and highlighted the role of acetic acid in seed germination.

New insights into the photo-degraded polystyrene microplastic: Effect on the release of volatile organic compounds

Excessive use of plastics leads to the ubiquity of plastic waste in the environment. Weathering can cause changes in the properties of plastics and lead to the release of various chemicals especially the volatile organic compounds (VOCs). Possible photodegradation pathway of polystyrene (PS) microplastics (MPs) was proposed and verified by the detection of VOCs. Headspace solid phase microextraction (HS-SPME) was employed to investigate the release behavior of VOCs from PS MPs exposed to simulated ultraviolet (UV). Results indicated that although the physicochemical properties of the PS MPs showed no significantly change after UV-irradiation, a variety of toxic VOCs, such as benzene, toluene, and phenol were detected from the irradiated MPs. UV irradiation progressively enhanced the release amount of VOCs with total concentration up to 66 μg g-1 after 30 d of exposure, about 2.4 times higher than that stored in the darkness (27 μg g-1). Some compounds (e.g., benzene and toluene) showed an upward trend over irradiation time, while others (e.g., styrene and 2-propenylbenzene) reduced over time. Results also found that the size of MPs could affect the release amounts but without consistent pattern for different VOCs detected in the headspace of the vial. In general, current study provided a new insight on the photo-aging process of MPs.

Investigation and Accounting Research of VOC in Daily and Specialty Ceramic Industry

With the deepening of modernization in China, the situation of air environmental pollution in China is very serious, and the environmental capacity is becoming less and less. Haze has gradually become one of the main sources of pollution in most cities in China. Volatile organic compounds (VOC) have the activity of participating in photochemical reactions and can participate in a variety of complex reactions in the atmosphere to promote the formation of haze and ozone. Through the experiment of daily ceramic flower paper baking, it can be concluded that the burning loss of flower paper accounts for more than 60% of the total quality of flower paper, and most of them are between 60% and 80%. Among them, the burning loss of PVB flower paper is about 80%, the water transfer paper is about 60%, and the low temperature flower paper is about 86%. In the experiment, the VOC proportion of low temperature flower paper, the PVB paper and water transfer paper accounted for 3.17%, 0.92% and 0.45%, respectively. Through the wax removal experiment of special ceramics molded by hot pressing, it is found that paraffin wax, beeswax and oleic acid are used as binders, and the amount of VOC emitted is also different when the dosage range is different; in addition, the burning loss is generally between 10% and 20% in the process of wax removal. The content of VOC in flue gas is about 0.42%, accounting for 0.046% of special ceramics. It provides an important basis for the calculation of VOC generated during the process of ceramic flower baking.

Impact of an Agriphotovoltaic System on Metabolites and the Sensorial Quality of Cabbage (Brassica oleracea var. capitata) and Its High-Temperature-Extracted Juice

To date, the impacts of agriphotovoltaic (APV) condition on the production yield of crop have been studied; however, the effect of APV production on the sensorial quality and consumer acceptability of the produce remains unexplored. Therefore, to address this knowledge gap, we cultivated “Winter Storm” cabbage under solar panels (20.16 kW) and in open field in 2020. The weight and diameter reduction rate of fresh cabbage grown under APV condition compared to open-field conditions were 9.7% and 1.2%, respectively. The levels of glucosinolates and their hydrolysis products were not significantly different in the fresh cabbage between the two conditions. The amount of volatile organic compounds, which may affect the perception of smell, were significantly higher in the cabbage juice prepared from the ones grown in open-field conditions than in the juice prepared from cabbages grown under APV conditions (n = 3, p < 0.01). However, untrained subjects could not distinguish the difference in the quality of the 2 sets of cabbage juices in the triangle test (n = 70, p = 0.724). Regardless of the distinguishing features of color, aroma, and taste, the subjects did not have any preference between the two different cabbage juices.

Adsorption of low-concentration organic pollutants from typical coal-fired power plants by activated carbon injection

Activated carbon (AC) injection was applied to remove the organic pollutants from coal-fired power plants. The total hydrocarbon (THC) concentration in flue gases was 0.512–0.998 mg/m3, aromatic hydrocarbons and oxygenated volatile organic compounds (VOCs) were the major components. With the AC injection (150 mg/m3), the THC was removed by 36.52–46.49%. The mesopores could capture some larger organic molecules and facilitate the intrapore diffusion. Improving the AC injection amount promoted the organic pollutant adsorption, but lowered the AC adsorption capacity. Removal performance of organic pollutants was affected by their physicochemical properties. The removal efficiency for most VOCs was within the range of 15–50%, while that was 45–90% for semi-VOCs. Minor amounts of VOCs achieved high removal efficiency through specific interactions, especially oxygenated VOCs. However, the removal efficiency of the total oxygenated VOCs was lower due to competition adsorption with inorganic components. AC injection had no significant effect on the physicochemical properties of fly ash. This work and results provide a feasible method and reference for the reduction of organic pollutants in coal-fired power plants and other combustion exhaust gases.

Chemical and Sensorial Characterization of Scented and Non-Scented Alstroemeria Hybrids

Floral scent plays an important ecological role attracting pollinators. Its composition has been elucidated for a vast diversity of species and is dominated by volatile organic compounds (VOCs) such as monoterpenoids, sesquiterpenoids, phenylpropanoids and benzenoid compounds. Considering that floral scent is also an important character for the ornamental plant market, this study was aimed at characterizing and comparing the molecular composition of scented and non-scented alstroemeria flowers. Confirmation of floral scent was performed through sensorial analysis, while GC-MS analysis detected monoterpenes and esters as major volatile organic compounds (VOCs). A total of 19 and 17 VOCs were detected in the scented hybrids 13M07 and 14E07, respectively. The non-scented hybrid 13B01 shared 14 VOCs with the scented hybrids, although it showed different relative concentrations. Comparison between scented and non-scented hybrids suggests that diversity and amounts of VOCs are likely due to the ecological role of scent, while the human perception of floral scent is not strictly related to the VOC profile.