Amount Of Volatile Organic Compounds Research Articles

Obtaining accurate non-methane hydrocarbon data for ambient air in urban areas: comparison of non-methane hydrocarbon data between indirect and direct methods

Abstract. Since non-methane hydrocarbons (NMHCs) include numerous species of volatile organic compounds (VOCs), they are the only indicators that can characterize the total amount of VOCs in ambient air. More than 90 % of NMHC instruments in the market use the indirect method for NMHC determination, utilizing a gas chromatograph to determine the concentrations of total hydrocarbons (THCs) and methane in air. However, we found indirect NMHC measurements incorrectly characterized the low NMHC concentrations in the urban air. These measurements were hindered by the uncertain changes in the errors associated with low THC concentrations, humidity and macroscopic substances (oxygen) in the atmosphere. In this study, we conducted intercomparisons between 10 instruments in the market using different operation principles; among these, two used the direct method, and eight used the indirect method. For the indirect method, experiments showed that when the NMHC concentration was 50 ppb C, the errors in the measurement results were 32 % (CH4) and 98 % (THC) when compared to theoretical values. The oxygen content in the sample gas directly affected the response of the THC. The effect of increased oxygen content on the analysis of oxygen-containing substances was more significant than that of the increase in hydrocarbon substances. The response of dry zero was blank, and the response value increased non-linearly with relative humidity (RH). RH had a great impact on low NMHC concentrations of nearly 50 %. For the direct method, although various flow designs were applied for different instruments, the results indicated that they generally showed lower interference and higher accuracy for the ambient NMHC measurements. With the online direct methods, we obtained more reliable data and characteristics for low-concentration NMHCs in downtown Shanghai. The median of hourly data was 163.1 ppb C, and the highest ratio of the maximum and minimum concentrations of NMHCs reached 9.56 in a single day.

Ozone containment through selective mitigation measures on precursors of volatile organic compounds

Abatement of volatile organic compounds (VOCs) ozone reduction is usually carried out by reducing the total amount of VOCs without considering reactivity between different species. This study incorporates the concept of maximum incremental reactivity (MIR) and speciation profiles into the industrial emission inventory of Taiwan to target organic species from industrial sources with the greatest ozone formation potentials (OFPs). These high OFP sources/species are then mitigated to assess the O3 reduction amount (ΔO3) with Community Multiscale Air Quality (CMAQ) modeling under VOC-limited conditions. The objective is to minimize the number of target sources/species and their tonnage while achieving maximum O3 reduction. This approach is referred to as the Selective Precursor Mitigation (SPM).A case study of a high ozone episode (September 4–10, 2020) was chosen for illustration, during which a relatively stagnant atmospheric condition with minimal transboundary ozone occurred. A series of scenarios to target the highest OFP chemicals/industries for mitigation are compared for the achievable max. ΔO3, areas affected (area coverage), and reduction efficiency. For instance, by reducing the ten leading industry classes with the island's highest OFPs (OFPind), up to 19 % of max. 1-h ΔO3 can be expected. If, however, the same tonnage of VOCs as that of OFPind is distributed to all industries without considering the reactivity, called the overall mitigation (OM), comparable results to those of OFPind were found, but the number of sources needed to be managed with OM would increase by nearly three times (29,662 for OM vs. 11,981 for OFPind). Further reducing the management scale by only zooming in the ten highest OFP chemicals within the ten leading OFP industries (OFPsp) would result in relatively limited area coverage. Still, major ozone hot spots could be alleviated.Although the domain is set on the island of Taiwan, the SPM approach is universally applicable to other regions worldwide to gain the maximum ozone reduction effect at a minimized societal cost.

Technical and environmental performance assessment of VOCs inhibited asphalt binders and mixtures

Asphalt materials will emit a large amount of volatile organic compounds (VOCs) under high temperature conditions, to address the environmental impact of asphalt pavement construction, this study selected different proportions of activated carbon (AC) and expanded graphite (EG) as composite inhibitors of asphalt VOCs, the road performance and environmental performance of asphalt mixtures are explored. Furthermore, the study proposed the VOCs resistance index (VRI) and VOCs environment-technique index (ETI) to evaluate the environmental and environmental-technical performance of asphalt mixture incorporating composite VOCs inhibitors. The results show that the VOCs inhibited asphalt mixtures with 5% AC-3% EG composite inhibitors has the best comprehensive environmental performance (80.15%), and its environmental technical performance (27.59%) is also the best, which is far higher than the other three VOCs inhibited asphalt mixtures. This study provides a reference and evaluation standard for the future development of efficient asphalt VOCs inhibitors.

Polymeric Fiber based 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 waterbased 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 availabl sand ecologically friendly solvent. Also nanomaterials is new field in research and development of material science field. Materials can be one dimensional such as small paricles, materilas can be two dimensional such as fibers. Therefore in two-dimensional materials such as fibers ( micro and nanofibers) use in many different applications such as medical, composites, aerospace, Bulding 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 waterbased coatings. Hence low VOC solvent water with high surface area fiber is becoming a trend in composite coating and nanotechnology in fibers. This review provides information on Composite coatings, distinct fibers used in coatings and their applications, effects of different sizes of fibers such as micro and nanofibers on coatings

Plasma Polymerization of Precipitated Silica for Tire Application.

Pre-treated silica with a plasma-deposited (PD) layer of polymerized precursors was tested concerning its compatibility with Natural Rubber (NR) and its influence on the processing of silica-silane compounds. The modification was performed in a tailor-made plasma reactor. The degree of deposition of the plasma-coated samples was analyzed by ThermoGravimetric Analysis (TGA). In addition, Diffuse Reflectance Infrared Fourier Transform spectroscopy (DRIFTs), X-ray Photoelectron Spectroscopy (XPS), and Transmission Electron Microscopy (TEM) were performed to identify the morphology of the deposited plasma polymer layer on the silica surface. PD silica samples were incorporated into a NR/silica model compound. NR compounds containing untreated silica and in-situ silane-modified silica were taken as references. The silane coupling agent used for the reference compounds was bis-(3-triethoxysilyl-propyl)disulfide (TESPD), and reference compounds with untreated silica having the full amount and 50% of silane were prepared. In addition, 50% of the silane was added to the PD silica-filled compounds in order to verify the hypothesis that additional silane coupling agents can react with silanol groups stemming from the breakdown of the silica clusters during mixing. The acetylene PD silica with 50% reduced silane-filled compounds presented comparable properties to the in-situ silane-modified reference compound containing 100% TESPD. This facilitates processing as lower amounts of volatile organic compounds, such as ethanol, are generated compared to the conventional silica-silane filler systems.

Exploitation of Selected Sourdough Saccharomyces cerevisiae Strains for the Production of a Craft Raspberry Fruit Beer.

Recent interest in the special beer category has encouraged the search for novel brewing materials, including new ingredients and novel yeast strains, in order to differentiate the finished products. The aim of this work was to select non-brewing S. cerevisiae strains for the production of a fruit beer with raspberry. The in vitro tests and the wort fermentations allowed the selection of two sourdough S. cerevisiae strains, showing high maltose and maltotriose consumption, high ethanol production, and high viability. Fruit beers (FB) and control beers (CB) without raspberries were prepared. Fruit addition accelerated sugar consumption (7 days compared to 13 days) and increased ethanol and glycerol production by yeasts. Raspberry addition and the inoculated yeast strongly affected the aroma profile of beers. FB samples showed a higher amount of volatile organic compounds (VOCs); the most represented classes were alcohols, followed by esters and acids. FB inoculated by the selected S. cerevisiae SD12 showed the highest VOCs concentration (507.33 mg/L). Results highlighted the possible application of sourdough yeast strains for the brewing process, which, combined with raspberry addition, can be exploited for the production of beers with enhanced aromatic features and suitable chemical properties.

VOCs emission from a final landfill cover system induced by ground surface air temperature and barometric pressure fluctuation

Volatile organic compounds (VOCs) emission flux and their concentration profiles were measured at a final municipal solid waste (MSW) landfill cover in Hangzhou, China. The influencing parameters, especially ground surface air temperature and pressure were monitored concomitantly. Furthermore, a numerical model incorporating coupled thermo-hydro-chemical interaction to assess VOCs emission from this final landfill cover (LFC) system was developed and validated with the field test results. The tested total VOC emission flux from the final cover is 0.0124 μg/m2/s, which indicates that the total amount of VOCs emitted into the atmosphere is 391 mg/m2 annually. Among these, dichloromethane (DCM) dominated VOCs emission flux during May, comprising 51.8% of the total emission flux. The numerical simulation results indicated that the diffusive emission flux of VOCs varied consistently with the fluctuation of atmospheric temperature. Whereas, the advective flux varied inversely with the fluctuation of barometric pressure. The highest difference in diffusive emission flux induced by temperature variation is 183 μg/m2/day and occurred in spring. Moreover, the results demonstrated that the impact of atmospheric temperature and pressure fluctuation on the emission of VOC from final covers is non-negligible when reasonably assessing the risks of landfill and landfill gas emission budget.

Emission factors and source profiles of VOCs emitted from coke production in Shanxi, China

Coking plants in China generate a substantial amount of volatile organic compounds (VOCs). The emission factors (EFs) of VOCs from coking plants are not well known, and thus, this study characterized the VOCs in the emissions from four coking plants in Shanxi, China. The EFs of VOCs from different stages of the coking process were calculated, and coal charging exhibited the highest EFs of VOCs, followed by the flue gases from combustion of coke oven gas, wastewater treatment, coke pushing and chemical byproduct recycling. The VOCs in emissions differed by coking process. Alkanes, aromatics and alkenes were the main VOCs emitted during the coking, wastewater treatment and chemical byproduct recycling processes, respectively. To effectively control the contribution of VOCs from coking processes to secondary organic aerosols and ozone formation, attention should be given to wastewater treatment and coal loading processes. The mean annual weight of VOCs emitted from coking plants in China from 2019 to 2021 was estimated to be 32.91 Gg with coking, chemical byproduct recycling, and wastewater treatment processes accounting for 91.34%, 7.85%, and 0.80% of total VOCs, respectively. An uneven spatial distribution of VOCs emissions in China was identified, with Shanxi, Shaanxi, Hebei, Inner Mongolia and Shandong being the largest contributors.

Study of synergistic effect of diatomite and modified attapulgite on reducing asphalt volatile organic compounds emission

The irritating flue gas generated during the heating process of asphalt is a serious emission pollution, causing both health risks and environmental hazards. In this work, a hybrid modified asphalt was prepared to reduce the volatile organic compounds (VOCs) emissions by using diatomite as the primary adsorption material and modified attapulgite as the flame retardant. The physical and rheological property tests showed that the compound of diatomite and modified attapulgite can improve the elevated temperature capability of the binder while slightly reducing the fatigue resistance. The results of the gas chromatography-mass spectrometer test (GC–MS) indicated that the total amount of VOCs released by the compound modifier modified asphalt was reduced by 81.5% compared with that of virgin asphalt (VA), the type of aliphatic hydrocarbons (ALHs) and hydrocarbon derivatives (HYDs) was also reduced by 77% and 92%, respectively. Scanning electron microscopy (SEM), simultaneous thermal (TG), and brunaurer emmett teller (BET) analysis showed that the mechanism of VOCs concentration reduction by the compound modifier might be chelation of dilution (water)-adsorption (hole)-blocking (insulating layer). This study provides a clean asphalt production method to reduce VOCs emission.

Volatile organic compounds and ionic substances contamination in cell processing facilities during rest period; a preliminary assessment of exposure to cell processing operators

IntroductionCell processing operators (CPOs) use a variety of disinfectants that vaporize in the workspace environment. These disinfectants can induce allergic reactions in CPOs, due to their long working hours at cell processing facilities (CPFs). Ionic substances such as CH3COO− generated from peracetic acid, nitrogen oxides (NOx) and sulfur oxides (SOx) from outdoor environment are also known to pollute air. Therefore, our objective was to assess the air quality in CPFs and detect volatile organic compounds (VOCs) from disinfectants and building materials, and airborne ionic substances from outdoor air. MethodsSampling was conducted at three CPFs: two located in medical institutions and one located at a different institution. Air samples were collected using a flow pump. Ion chromatographic analysis of the anionic and cationic compounds was performed. For VOC analysis, a thermal desorption analyzer coupled with capillary gas chromatograph and flame ionization detector was used. ResultsAnalysis of the ionic substances showed that Cl−, NOx, and SOx, which were detected in large amounts in the outdoor air, were relatively less in the CPFs. Ethanol was detected as the main component in the VOC analysis. Toluene was detected at all sampling points. As compared to the other environments, air in the incubator contained larger amounts of VOCs, that included siloxane, tetradecane, and aromatics. ConclusionsNo VOCs or ionic substances of immediate concern to the health of the CPOs were detected during the non-operating period. However, new clinical trials of cell products are currently underway in Japan, and a variety of new cell products are expected to be approved. With an increase in cell processing, health risks to CPOs that have not been considered previously, may become apparent. We should continue to prepare for the future expansion of the industry using a scientific approach to collect various pieces of information and make it publicly available to build a database.

Qualitative and Quantitative Recognition of Volatile Organic Compounds in Their Liquid Phase Based on Terahertz Microfluidic EIT Meta-Sensors

Volatile organic compounds (VOCs) are directly associated with human health concerns and environment safety. Therefore, it is urgent to achieve an accurate detection of VOCs both qualitatively and quantitatively. In this work, the qualitative detection of ethyl benzene (EB), isopropyl alcohol (IPA), ethyl acetate (EA) – three pure VOCs in liquid phase were discussed using terahertz (THz) microfluidic Electromagnetic Induced Transparency (EIT) meta-sensor. The THz response illustrated that with an increase in VOCs’ volumes (1~6μL), resonant frequencies of dual transmission dips (0.855, 1.724 THz) and the EIT peak (1.213THz) exhibited red shift. The limit of detections for pure IPA, EA, EB can achieve 5.45μg, 13.46μg, 4.35μg, respectively. The multivariate fusion (MF) model based on the EIT responses to VOCs was utilized to improve the accuracy of trace detection and classification of VOCs. Furthermore, the above method combined with principal component analysis with Gaussian mixture model (PCA-GMM) and the neural network classification algorithm support vector machine (SVM) was applied to the recognition of VOCs. In addition, the THz method is not feasible to detect trace amounts of VOCs (typically 0.3mg/L) in waste water because water is highly absorbable in THz band and VOCs will evaporate if water is removed. Here, IPA, EA, EB in soil were detected and classified by PCA-GMM combined with MF. Our results provide a new terahertz meta-sensor platform to trace detection of VOCs in liquid phase and in soil and may be used to identify hazardous wastes in illegal dumping.

Plant viruses induce plant volatiles that are detected by aphid parasitoids

Aphis gossypii (Sternorrhyncha: Aphididae) aphids are vectors of important plant viruses among which cucumber mosaic virus (CMV) and potato virus Y (PVY). Virus-infected plants attract aphid vectors and affect their behavior and growth performance either positively or negatively depending on mode of transmission. Viruses cause changes in the composition and the amount of volatile organic compounds (VOCs) released by the plant that attract aphids. The aphid parasitoid Aphidius colemani (Hymenoptera: Aphelinidae) has been shown to have higher parasitism and survival rates on aphids fed on virus-infected than aphids fed on non-infected plants. We hypothesized that parasitoids distinguish virus-infected plants and are attracted to them regardless of the presence of their aphid hosts. Herein, we examined the attraction of the A. colemani parasitoid to infected pepper plants with each of CMV or PVY without the presence of aphids. The dynamic headspace technique was used to collect VOCs from non-infected and CMV or PVY-infected pepper plants. Identification was performed with gas chromatography-mass spectrometry (GC–MS). The response of the parasitoids on virus-infected vs non-infected pepper plants was tested by Y-tube olfactometer assays. The results revealed that parasitoids displayed a preference to CMV and PVY infected plants compared to those that were not infected.

Application of 6-Pentyl-α-Pyrone in the Nutrient Solution Used in Tomato Soilless Cultivation to Inhibit Fusarium oxysporum HF-26 Growth and Development

Soilless cultivation has increased in China. Like vegetables or ornamental plants, tomatoes can be cultivated in soilless culture systems. Fusarium wilt (FW) is an economic tomato disease. The nature and amount of volatile organic compounds in Trichoderma asperellum PT-15 were investigated, and 6-pentyl-α-pyrone (6-PP) was detected. Furthermore, the effect of 6-PP on Fusarium oxysporum HF-26 was evaluated. Results revealed that 25 mg/L 6-PP was the optimal concentration inhibiting F. oxysporum HF-26 and that the content of fusaric acid decreased considerably compared to that of the control. FUB1, FUB4, and FUB10 toxin synthesis and transport genes were downregulated. Additionally, VelA, velB, and LaeA genes were downregulated, reducing F. oxysporum mycelial growth and hyphae formation. 6-PP was added to the soilless culture solution in a greenhouse experiment. The results showed that an antifungal–nutrient solution containing 25 mg/L 6-PP significantly suppressed FW with 70.71% efficacy and a 27.23% disease index (DI), which were higher efficacy and lower DI than that of the control. Furthermore, treatment with an antifungal–nutrient solution containing 6-PP increased the levels of defence enzymes 24 h post-inoculation (hpi) compared with those at other time periods. The relative expression levels of the PR1, NPR1, PR2, and PR5 genes were considerably upregulated at 24 hpi.

Volatile profile, textural and sensory properties of Diyarbakır Örgü cheese produced from sheep and cow milk of different ripening time

Diyarbakır Örgü (knitted) cheese (DOC) is a semi-fat, hard, and a pasta-filata type cheese. The objective of this study was to evaluate volatile organic compounds (VOC), and textural and sensory properties of DOC during the 120-day maturation period. For this purpose, a total of 5 different cheeses were produced as 100% sheep’s milk (C1), 100% cow’s milk (C2), 90% sheep’s milk + 10% cow’s milk (C3), 80% sheep’s milk + 20% cow’s milk (C4), and 70% sheep’s milk + 30% cow’s milk (C5). During the ripening, a total of 31 compounds, including esters (9), alcohols (5), acids (5), ketones (5), aldehydes (4), and miscellaneous (3), were identified in all cheese samples. Volatile compounds increased, both qualitatively and quantitatively, along with the increase of the percentage of sheep milk used in the cheese production increased. At the beginning of ripening, the total amount of VOC in the DOC obtained from sheep’s milk was 3.27-fold greater than that of the produced cow’s milk, while this ratio increased to 4.57 at the end of ripening. The total VOC contents of all the DOC reduced along the ripening and decreased by 53.37, 64.92, 15.53, 51.81, and 64.84% for C1, C2, C3, C4, and C5, respectively. As the amount of cow's milk used in DOC production increased, the values of all textural properties (hardness, adhesiveness, springiness, cohesiveness, gumminess, and chewiness) of the cheese increased too. On the other hand, these values decreased with the maturation (p<0.05). The rates of decrease in hardness (N), adhesiveness (N.s), springiness (cm), cohesiveness, gumminess (N), and chewiness (mJ) values of the cheese groups with the storage were C1>C3>C2>C4>C5, C4>C1>C5>C2>C3, C2>C1>C3>C4>C5, C3>C2>C1>C5>C4, C1>C4>C3>C2>C5 and C3>C4>C1>C5>C2, respectively. In terms of sensory properties (colour, texture and, taste-aroma) of the cheese mature C2, mature C1 and 30-day ripened C1 cheese samples were preferred more, respectively.

Emission of Volatile Organic Compounds in Crumb Rubber Modified Bitumen and Its Inhibition by Using Montmorillonite Nanoclay

Bitumen emits a large amount of volatile organic compounds (VOCs) during the production and construction of asphalt mixture, which can cause both environmental hazards and health risks. In this study, a setup was designed to collect the VOCs released by base and crumb rubber-modified bitumen (CRMB) binders and their composition was characterized by thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS). Next, organic montmorillonite (Mt) nanoclay was added into CRMB binder and its inhibiting effect on the VOCs emission of the binder was investigated. Finally, the VOCs emission models for the CRMB and Mt-modified CRMB (Mt-CRMB) binders were established according to reasonable assumptions. The results indicated that the VOCs emission of CRMB binder was 3.2 times larger than that of the base binder. Due to its intercalated structure, the nanoclay can reduce the VOCs emission of CRMB binder by 30.6%. Especially, its inhibition effects on alkanes, olefins, and aromatic hydrocarbons were more significant. After finite element verification, the established model based on the Fick's second law can describe the emission behavior of CRMB and Mt-CRMB binders well. Overall, the Mt nanoclay can be used as an effective modifier to inhibit the VOCs emission of CRMB binder.

Volatile Organic Compounds in Patients’ Breath during Conversation

Purpose: The protracted coronavirus disease (COVID-19) pandemic has caused an unprecedented global health, social, economic, and psychological crisis. COVID-19 is transmitted via droplets, which include volatile organic compounds (VOCs) emitted by COVID-19 carriers. As a result, medical healthcare workers interacting with COVID-19 patients are at a high risk of infection. In this study, we measured the concentration of total VOCs (TVOCs) in the droplets of patients during conversations. Methods: Thirty patients aged 20–88 years were enrolled in this study. The amounts of VOCs, formaldehyde (HCHO), and carbon dioxide (CO2) as surrogate parameters for the patient’s droplets were measured at a distance of 1 m from the patients under the following conditions: 1) no conversation with a mask on, 2) conversation with a mask on, 3) conversation without a mask on, and 4) no conversation without a mask on. Results: The average concentrations of TVOCs (mg/m3), HCHO (mg/m3), and CO2 (ppm) were all the lowest before the masked conversation (1.79 ± 1.72, 0.25 ± 0.25, 1193 ± 516), increased during the masked conversation (1.99 ± 1.87, 0.29 ± 0.24, 1288 ± 555), were the highest during the unmasked conversation (3.10 ± 1.86, 0.45 ± 0.28, 1705 ± 729), and decreased to baseline after the unmasked conversation (1.89 ± 1.88, 0.26 ± 0.27, 1191 ± 518, respectively). Variations in TVOC and HCHO concentrations were positively correlated with patient age (TVOC: r = 0.42, p = 0.019 and HCHO: r = 0.47, p = 0.008). Conclusion: Wearing a mask reduced the VOC concentrations measured during conversations more than when a mask was not worn. Therefore, wearing a mask can reduce the emission of airborne droplet-derived VOCs and thereby reduce the risk of transmission of unknown patient-derived infections. Clinical Trial Registration no: The Clinical Trial Registration no: (UMIN000039595)

Behavioural Response of Whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) Towards Volatile Organic Compounds Emitted from Eggplant Leaves

The whitefly Bemisia tabaci is considered one of the most destructive insect pests that can attack several vegetable crops worldwide. The behavior of choosing a host plant by whitefly can be significantly influenced by volatile organic compounds. The aim of this investigation is to identify and bioassay the volatile organic compounds emitted from uninfested and infested eggplant leaves with B. tabaci. The current study focuses on the interaction between whitefly and eggplant with the identification of volatile organic compounds emitted from leaves that were collected by headspace solid phase microextraction fiber and gas chromatography mass spectrum analyzed. Both uninfested and infested eggplant leaves released a total of 11 compounds. The amount of volatile organic compounds emitted from affected eggplant leaves by whitefly was higher than from uninfested eggplant leaves. Using a Y-shaped olfactometer bioassay, whitefly preferred to attract toward volatile emitted by eggplant leaves in both uninfested and infested eggplant leaves. Our results suggest these chemical compounds can play a key mediator in host finding behavior. The exploitation of one or more of these compounds can apply in an integrated management program of this pest as a lure in the sticky trap or manipulating insect behavior.

The volatile organic compounds emission mechanism of pretreated bamboo during heat treatment

Heat treatment can be used to improve bamboo product quality. Pretreatment of the bamboo material can reduce the energy consumption of heat treatment. However, large quantities of volatile organic compounds (VOCs) are released during the bamboo heat treatment process, causing potential problems for the environment and human health. In this study, the effects of pretreatment with sodium hydroxide and zinc chloride solutions on VOCs emissions during heat treatment were investigated. We also explored chemical and structural changes of heat-treated bamboo. The VOCs released by untreated bamboo during heat treatment were mainly aldehydes, alcohols, alkanes, and esters. Alcohol and alkane contents decreased as treatment temperature increased, accompanying the emergence of more complex chemicals. Compared with untreated bamboo, sodium hydroxide pretreatment destroyed the hemicellulose structure, released stable VOCs under heat treatment, and did not produce acidic compounds; ether compounds increased significantly with increase in temperature. The catalysis of zinc chloride pretreatment degraded hemicellulose during heat treatment. The relative contents of aldehydes and esters released from zinc chloride pretreated bamboo during heat treatment increased significantly with temperature. Up to 69.76 % of aldehyde compounds were released at 160 °C, among which the relative proportion of furfural reached 37.23 %. These results may provide theoretical support for controlling VOCs emissions from different pretreated bamboo materials during heat treatment, which is also conducive to the subsequent recycling of VOCs.

Emission Control of Toluene in Iron Ore Sintering Using Catalytic Oxidation Technology: A Critical Review

Iron ore sintering flue gas containing large amounts of volatile organic compounds (VOCs) can form secondary photochemical smog and organic aerosols, thus posing a serious threat to human health and the ecological environment. Catalytic combustion technology has been considered as one of the most prospective strategies for VOC elimination. This paper focuses on a review of studies on catalytic removal of typical VOCs (toluene) on transition metal oxide catalysts in recent years, with advances in single metal oxides, multi-oxide composites, and supported metal oxide catalysts. Firstly, the catalytic activities of a series of catalysts for toluene degradation are evaluated and compared, leading to an analysis of the key catalytic indicators that significantly affect the efficiency of toluene degradation. Secondly, the reaction pathway and mechanism of toluene degradation are systematically introduced. Considering the site space and investment cost, the conversion of VOC pollutants to harmless substances using existing selective catalytic reduction (SCR) systems has been studied with considerable effort. Based on the current development of simultaneous multi-pollutant elimination technology, the interaction mechanism between the NH3-SCR reaction and toluene catalytic oxidation on the surface is discussed in detail. Finally, views on the key scientific issues and the challenges faced, as well as an outlook for the future, are presented. This overview is expected to provide a guide for the design and industrial application of NO/VOC simultaneous removal catalysts.

Co-cultivation of Mortierellaceae with Pseudomonas helmanticensis affects both their growth and volatilome

Volatile organic compounds (VOCs) might mediate microbial interactions, especially in spatially structured environments, such as soil. However, the variety and specificity of VOC production are poorly understood. Here, we studied 25 Mortierellaceae strains belonging to the genera Linnemannia and Entomortierella in both pure and co-culture with Pseudomonas helmanticensis under laboratory conditions. We analysed both the fungal growth depending on co-cultivation and the cultures’ volatilomes applying proton-transfer-reaction time-of-flight and gas chromatography-mass spectrometry (PTR-ToF-MS and GC–MS). In a strain-specific manner, we found the fungi’s radial growth rate and colony morphology affected by the presence of P. helmanticensis. The fungus seemed to generally reduce the bacterial growth. The volatilomes of the fungal and bacterial pure and co-cultures were diverse. While the fungi frequently consumed VOCs, P. helmanticensis produced a higher diversity and amount of VOCs than any fungal strain. Our results support that both the pure and co-culture volatilomes are taxonomically conserved. Taken together, our data supports the relevance of VOCs in Mortierellaceae-P. helmanticensis interaction. We also discuss individual VOCs that appear relevant in the interaction.