This paper is a review on the treatment of volatile organic compounds using absorbents. Volatile organic compounds (VOCs) are carbon-based compounds with a boiling point ranging from 50℃ to 250℃. VOCs have been considered as contributors of photochemical smog and global warming as well as hazards to human health. VOCs can be removed by a variety of methods, including those that are destructive (incineration, catalytic oxidation, and biodegradation) and non-destructive (adsorption, absorption, and condensation). The removal performance of VOCs in the gas phase is influenced by gas-liquid mass transfer and/or the microbial activity depending on VOC properties such as solubility, diffusivity, bioavailability, and toxicity. Since the usual processes for VOCs removal involve water as a VOC absorbent, it is necessary to improve the removal efficiency of hydrophobic VOCs. In addition, VOC removal processes do not appear to show consistently satisfactory performance due to transient high-strength VOC loading in practical fields. To increase the gas-liquid mass transfer of hydrophobic VOCs and to prevent the functional deterioration due to transient high loading, the use of nonaqueous phase VOC absorbents is a promising strategy. This review offers a critical overview of the types, properties, and the applications of the VOC absorbents, including liquid organic solvents, ionic liquids, and solid polymers. This paper also details the advantages by employing the VOC absorbents for the removal of hydrophobic VOCs in the integrated process, absorption and biodegradation coupling process. The challenges of and future perspectives on the development of efficient VOC removal processes using VOC absorbents are briefly discussed.

This study investigated the chemical composition of burdock (Arctium lappa L.) leaves essential oil, and the quantitative changes of the major terpene compounds according to the specific harvesting season. The essential oils obtained by the hydrodistillation extraction (HDE) method from the aerial parts of the burdock leaves were analyzed by gas chromatography (GC) and GC-mass spectrometry (GC-MS). The essential oil composition of this plant was characterized by the higher content of phytol and 6,10,14-trimethyl-2-pentadecanone. Seventy seven (98.28%) volatile flavor compounds were identified in the essential oil from the burdock leaves harvested during the spring season of 2012, and phytol (33.47%) and 6,10,14-trimethyl-2-pentadecanone (32.47%) were the most abundant compounds. Eighty eight (99.08%) compounds were identified in the essential oil from the leaves harvested during the autumn season of 2012, and in this case, phytol (37.35%) and 6,10,14-trimethyl-2-pentadecanone (34.67%) were also the most abundant compounds. These two volatile components were confirmed as the major oil components of the burdock leaves during the time of any harvest. The ratio between the two components contained in the burdock essential oils did not differ significantly by harvesting season. But overall, the essential oil harvested during the spring season contained 65.94% of the two major components, while for the essential oil harvested during the autumn season, the total amount of these two major components was 72.02%. While the main ingredients of the essential oils were found to be unchanged from one harvest time to the next, it was found to differ in content. For the burdock leaves, the quality index of the volatile constituents according to the harvest time would be more useful for utilizing the total quantity other than the proportion between phytol and 6,10,4-trimethyl-2-pentadecone.

The potato tuber moth (PTM) is a cosmopolitan insect pest and hosts various solanaceous crops including tomato. We tested olfactory behavior and larval development of PTM on different varieties of tomato fruit namely, Money maker, Campari, Ailsa craig, LA 3475 (M82) and E-6203, and one wild species, S. pimpinellifolium. We also analyzed essential oil of the tomato fruits through GC/MS. There were significance differences in immature developmental period and head capsule size among the tested varieties. PTM larvae showed highest survival on Ailsa craig (66.0±6.0) and E-6203 (64.0±4.0) and lowest on S. pimpinellifolium (14.0±6.0). The major compounds found in the tomato fruit’s essential oils include n-hexadecanoic acid (14.2%) and 2-octylcyclopropaneoctanal (8.7%) in Money makers; hexadecanoic acid, 2-hydroxy -1-(hydroxymethyl) ethyl ester (13.1%) in Campari; tert-hexadecanethiol (6.8%) and 1,4-benzenedicarboxylic acid, bis (2-ethylhexyl) ester (6.2%) in Ailsa craig; (Z)-13-docosenamide (13.39) in S. pimpinellifolium; Eicosane (4.4%,), (Z)-9 -octadecenamide (4.2%), and n-hexadecanoic acid (4.1%) in E-6208. The larval development result on tomato fruit could support its suitable nutritional contents to PTM, posing pest potential in the future where higher exposure is expected.

In South Korea, increase in kimchi import from China has emphasized the importance of noticing the origin of production area, largely because of the price and safety concerns. Nevertheless, identification of it depends on a complex physicochemical method. Hence, the objective of this study is to develop a statistical algorithm applicable for analyzing volatile compounds measured by electronic nose so that the device can be used for simple classification of kimchi by its production origin. Discriminant function analysis (DFA), one of multi-variate analysis, was mainly used for analyzing big-size data of volatile compounds detected from kimchi produced either in South Korea or China. Result showed that DFA could completely separate 69 varieties of kimchi by its origin of production (39 from South Korea and 30 from China). This result suggests that volatile compounds can be an index for identifying origin of kimchi and consequently, electronic nose is an optimal option for identifying origin of kimchi production when combined with multi-variate statistics.

In this study, a method to produce a fine volatile powder extracted from shiitake mushrooms using spray freeze-drying (SFD) was investigated. The analysis of the water-soluble aromatic compounds was carried out by headspace solid phase micro-extraction (HS-SPME) coupled withgas chromatography-mass spectrometry (GC-MS). Scanning electron microscopy (SEM) and laser particle size analysis were applied to characterizethe physical structure and size distribution of the SFD-derivedparticles. Eleven key volatile compounds were identified in the extracts of shiitake mushroomspre- and post-SFD. Recoveries of aromatic volatiles ranging from 30.9 - 82.9% were observed in the overall flavor profile results from the powder obtained with SFD. SEM analysis demonstrated that the particles of the aromatic powderwere spherical in nature, having highly porous surfaces andmean diameters of 19.3 μm.

The aim of this study was to examine indoor fungal concentration and fungal volatile organic compounds(VOCs) in single-person households. A total of 22 houses occupied by one person were investigated in this study. 19 VOCs detected in the field were estimated as fungi-derived VOCs through a review of the literature, and 11 VOCs were confirmed as fungal VOCs by laboratory experiments. Exposure to fungal VOCs in the indoor environment has been confirmed to be highly influenced by airborne fungal concentration and indoor humidity. 3-octanone was characterized by a clear generation profile in Aspergilus versiocolor, and n-decane in Pencillum chrysogenum. ntetradecane emitted by Stachybotrys chartarum exhibited a tendency to occur consistently. The observations made in this study demonstrated that single-person households can easily be exposed to fungi, and MVOCs can be used as an indicator of fungal exposure in indoor environments.

The present study was conducted to determine the optimal supplementation level of beta-mannanase in the diet of laying hens. A total of 320 Hy-Line Brown layers (80 weeks of age) were assigned randomly into four groups on the basis of laying performance. Each treatment had eight replicates with 10 birds each (80 birds per treatment). Two hens were caged individually. Treatments were basal diet supplemented with 0 (control), 0.04, 0.08, and 0.16% beta-mannanase during the nine-week feeding period. Laying hens fed diets supplemented with increasing levels of beta-mannanase had increased (linear, p<0.05) overall egg production and egg mass. In addition, these hens had greater retention of dry matter, crude protein, gross energy, calcium, and mannan (linear, p<0.05). Dietary beta-mannanase treatments had no effect on blood metabolites such as total carbohydrate, triglycerides, glucose, total protein, and blood urea nitrogen, or excreted ammonia nitrogen and volatile fatty acids. The results obtained in present study indicate that dietary supplementation of beta-mannanase has the potential for improving the performance of laying hens. The optimal supplementation level is 0.04% beta-mannanase in the diet.

Acetate, propionate, butyrate are the major soluble volatile fatty acids metabolites of fermented food waste leachates. This work investigate the effects of volatile fatty acid on the growth rate and NH4-N, PO4-P removal efficiency of mixotrophic microalgae Chlorella vulgaris to treat digested food waste leachates. The results showed that acetate, propionate and butyrate were efficiently utilized by Chlorella vulgaris and microalgae growth was higher than control condition. Similar trends were observed upon NH4-N and PO4-P consumption. Volatile fatty acids promoted Chlorella vulgaris growth, and nutrient removal efficiencies were highest when acetate was used, and butyrate and propionate showed second and third. From this work it could be said that using mixotrophic microalgae, in this work Chlorella vulgaris, fermented food waste leachates can be treated with high efficiencies.

This study investigated the quality characteristics and volatile flavor components of aronia wine (Aronia melanocarpa (0~100%)). After 12 days of fermentation, the alcohol contents of aronia wines ranged between 9.0~12.0%. The pH level and total acidity of aronia wines were 3.20~3.68 and 0.57~0.76 g/100 mL, respectively. The organic acid analysis of wine containing 100% aronia, revealed malic acid content at 3.70 mg/mL, followed by tartaric acid, lactic acid, and citric acid. As the aronia content increased, both the total polyphenol content and the antioxidant activity (the DPPH radical scavenging activity) also significantly increased. The total polyphenol content was the highest in the wine with 100% aronia (461.33 mg%), and the antioxidant activity showed the highest values in the wine with 100% aronia (91.91%). Volatile flavor component analysis of aronia wines identified 8 alcohols, 12 esters, 4 ketones, and 7 other compounds. In the sensory evaluation, the color, flavor, and taste of wine with 20% aronia showed higher values than other aronia wines. Based on the results of the present study, we suggest that 20% aronia is most beneficial in improving the quality as well as sensory characteristics of the wine.

This study investigated the chemical composition of headspace gas from white-flowered lotus (Nelumbo nucifera Gaertner). Volatile flavor compositions of headspace from white-flowered lotus (floral leaf, stamen, flower stalk, stem) were investigated through the solid-phase microextraction method using polydimethylsiloxane-divinylbenzene fiber. The headspace was directly transferred to a gas chromatography-mass spectrometry. Sixty-three volatile flavor constituents were detected in the headspace of lotus floral leaves, and undecanoic acid (7.81%) was the most abundant component. Fifty-three volatile flavor constituents were detected in the headspace of lotus stamina, and isobutylidene phthalide (7.94%) was the most abundant component. Forty-four volatile flavor constituents were detected in the headspace of lotus flower stalks, and 3-butyl dihydrophthalide (11.23%) was the most abundant component. Fifty-nine volatile flavor constituents were detected in the headspace of lotus stems, and ligustilide (16.15%) was the most abundant component. The content of phthalides was higher in the headspace of flower stalks and stems, while alcohols and acids were the predominant compounds in lotus floral leaves.

The physicochemical properties of dry wine produced from domestic kiwifruit according to production year from 2008 to 2012 were studied. pHs of wine were from 4.02(F wine, production year 2009, sterilized) to 4.11(D wine, production year 2012, non-sterilized) and their acidities were lowest in D wine(0.79%) and highest in F wine(1.18%). All the wines have the same soluble solids of 8 °brix and 12% of alcohol, respectively. The reducing sugar was lowest in A wine(production year 2008, non-sterilized) and highest in D wine. The lactic acid was detected as a main organic acid and the free sugar was detected only fructose. As main flavor components, ethyl acetate and 1-pentanol were detected and their sum of 80~90% and a small amount of phenylethyl alcohol which providing rose-like aroma was also detected. The contents of soluble phenolics were highest in D wine(1.07 g/L) and lowest in C wine(0.80 g/L), corresponding to the antioxidant activity was highest found in D wine according to their soluble phenolic contents.

There has been growing concern over the emissions of formaldehyde and VOCs from automotive interior materials, as these could have an important impact on the in-vehicle air quality (IVAQ) of automotive vehicles. Odor along with VOCs refers to the automotive interior smell emitted directly or indirectly from any part of an automotive interior, based on human olfactory senses and a comfort evaluation of vehicle quality. The objective of this paper is to compare the odor intensity using GC/MS analysis method and odor sensory test in accordance with ISO 12219-2. For the compounds having low odor threshold value and high VOC concentration, it was found that there was the same tendency in each field of odor whether the instrument analysis method or the odor sensory test method was used.

Per capita nail-products use and airborne VOCs emission in four techniques of nail care (full coat coloring, UVgel polish, repair silk, and acrylic overlay) are estimated in this study. These assessments were carried out in a sealed test chamber using artificial hand and nails. A polish remover and a gel cleanser as cleanser and acrylic liquid as solvent were the most commonly used nail products in all 4 of the nail care techniques. Acetone, isopropyl alcohol, and methanol, which are major components of a polish remover, were commonly detected in all nail care techniques while acetone was detected the most. In addition to these airborne VOCs, a variety of other components such as ethyl acetate, cyclohexane, and toluene were identified in full coat coloring technique. In the process of UV-gel polish care technique, the main airborne VOCs were caused by solvents and were not involved in the curing process of UV gels (base gel and top gel) and gel bonder. In the case of repair silk nail care techniques, which generated the most VOCs, the total amount of VOCs detected was about 1,118.8 ± 359.6 mg/capita. Of the VOCs, butane (862.2 ± 283.9 mg/capita), which is contained in glue dryer, represented the largest share. In the process of acrylic overlay nail care technique, ethyl methacrylate (EMA), which is the basic element of acrylic, and highly toxic methyl methacrylate (MMA) were detected at 396.6 ± 42.3 mg/capita and 141.8 ± 8.2 mg/capita, respectively. The per capita data is very useful in designing a ventilation system for environmental improvement of a nail shop and setting a health care policy for nail artists and customers.