► We review the current status of catalytic and non-catalytic VOC abatement based on a vast number of research papers. ► The underlying mechanisms of plasma–catalysis for VOC abatement are discussed. ...► Critical process parameters that determine the influent are discussed and compared.
This paper reviews recent achievements and the current status of non-thermal plasma (NTP) technology for the abatement of volatile organic compounds (VOCs). Many reactor configurations have been developed to generate a NTP at atmospheric pressure. Therefore in this review article, the principles of generating NTPs are outlined. Further on, this paper is divided in two equally important parts: plasma-alone and plasma–catalytic systems. Combination of NTP with heterogeneous catalysis has attracted increased attention in order to overcome the weaknesses of plasma-alone systems. An overview is given of the present understanding of the mechanisms involved in plasma–catalytic processes. In both parts (plasma-alone systems and plasma–catalysis), literature on the abatement of VOCs is reviewed in close detail. Special attention is given to the influence of critical process parameters on the removal process.
Dampness affects a substantial percentage of homes and is associated with increased risk of respiratory ailments; yet, the effects of dampness on indoor chemistry are largely unknown. We hypothesize ...that the presence of water‐soluble gases and their aqueous processing alters the chemical composition of indoor air and thereby affects inhalation and dermal exposures in damp homes. Herein, we use the existing literature and new measurements to examine the plausibility of this hypothesis, summarize existing evidence, and identify key knowledge gaps. While measurements of indoor volatile organic compounds (VOCs) are abundant, measurements of water‐soluble organic gases (WSOGs) are not. We found that concentrations of total WSOGs were, on average, 15 times higher inside homes than immediately outside (N = 13). We provide insights into WSOG compounds likely to be present indoors using peer‐reviewed literature and insights from atmospheric chemistry. Finally, we discuss types of aqueous chemistry that may occur on indoor surfaces and speculate how this chemistry could affect indoor exposures. Liquid water quantities, identities of water‐soluble compounds, the dominant chemistry, and fate of aqueous products are poorly understood. These limitations hamper our ability to determine the effects of aqueous indoor chemistry on dermal and inhalation exposures in damp homes.
•Esters, alcohols, ketones, hydrocarbons, alkanes and aldehydes were the mainly VOCs in passion fruit.•VOCs accumulated gradually, especially the change of esters is the most significant during ...passion fruit ripening.•‘Color change stage’ was key period for aroma formation in passion fruit.•Ester biosynthesis pathway and genes (AAT, LOX and HPL) were identified as active during ripening.
Passion fruit is a tropical liana of the Passiflora family that is commonly consumed throughout the world due to its attractive aroma and flavor. However, very limited information is available on the mechanism of aroma formation and composition of the passion fruit during ripening. Therefore, HS-SPME-GC/MS combined with transcriptome analysis was used to study the mechanism of aroma formation during passion fruit ripening. The profile analyzed included 148 volatile organic compounds (VOCs) and related differentially expressed genes (DEGs). Compared with SA, 85 VOCs and related DEGs were identified as significantly upregulated at the SB and SC stages, including esters, alcohols, ketones, hydrocarbons, alkanes, and aldehydes. Two main pathways, ester and amino acid metabolism, and related genes were analyzed with VOC biosynthesis in passion fruit. This study is the first analysis of passion fruit VOC formation and provides new insights into the flavor mechanism and quality breeding of passion fruit.
is an aerobic, gram-positive, endospore-forming bacterium that promotes plant growth. Numerous strains of this species have been reported to suppress the growth of microbial pathogens, including ...bacteria, fungi, and nematodes. Based on recent phylogenetic analysis, several
species have been reclassified as
. However, this information has yet to be integrated into a well-organized resource. Genomic analysis has revealed that
possesses strain-specific clusters of genes related to the biosynthesis of secondary metabolites, which play significant roles in both pathogen suppression and plant growth promotion. More specifically,
exhibits a high genetic capacity for synthesizing cyclic lipopeptides (i.e., surfactin, bacillomycin-D, fengycin, and bacillibactin) and polyketides (i.e., macrolactin, bacillaene, and difficidin). Secondary metabolites produced by
can also trigger induced systemic resistance in plants, a process by which plants defend themselves against recurrent attacks by virulent microorganisms. This is the first study to integrate previously published information about the
species, newly reclassified as
, and their beneficial metabolites (i.e., siderophore, bacteriocins, and volatile organic compounds).
•The SPME/GC–MS analysis of wheat organic volatiles was implemented.•158 VOCs, of which 98 never found before in wheat kernels, were identified.•Pedoclimatic conditions were the highest source of ...variability in VOCs profile.•Selected VOCs permitted to discriminate among wheats cultivated in different areas.•Selected VOCs permitted to discriminate between durum and common wheat.
Food volatile organic compounds (VOCs) analysis is a useful tool in authentication and classification processes, but, to date, the analysis of wheat VOCs is still little explored. In this study a method of analysis based on solid phase microextraction coupled with gas chromatography-mass spectrometry was optimized by testing different types of fibers, sample preparation methods and amounts, extraction temperatures and times, desorption times and oven programs. The analysis was applied to six wheat cultivars harvested in different areas, and permitted to identify 158 VOCs, of which 98 never found before. A principal component analysis performed on the dataset showed that the area of cultivation accounted for the highest source of variability. Partial least squares analysis permitted to correctly classify wheats based on their cultivation area and species, and to identify the most discriminant VOCs. These results are promising for the study of the influence of geographical origin on wheat quality.
Plants synthesize volatile organic compounds (VOCs) to attract pollinators and beneficial microorganisms, to defend themselves against herbivores and pathogens, and for plant-plant communication. In ...general, VOCs accumulate in and are emitted from the tissue of their biosynthesis. However, using biochemical and reverse genetic approaches, we demonstrate a new physiological phenomenon: inter-organ aerial transport of VOCs via natural fumigation. Before petunia flowers open, a tube-specific terpene synthase produces sesquiterpenes, which are released inside the buds and then accumulate in the stigma, potentially defending the developing stigma from pathogens. These VOCs also affect reproductive organ development and seed yield, which are previously unknown functions of terpenoid compounds.
The effectiveness of Wickerhamomyces anomalus, Metschnikowia pulcherrima and Saccharomyces cerevisiae as biocontrol agents on postharvest decay of strawberry (Fragaria x ananassa, cv. ‘Alba’) fruit, ...and their inhibitory activities on some decay-causing fungi were evaluated. Volatile organic compounds from these yeasts decreased mycelial growth of Botrytis cinerea by 69%, and by less for Monilinia fructicola, Alternaria alternata, Aspergillus carbonarius, Penicillium digitatum, Cladosporium spp., and Colletotrichum spp. Strawberry fruit exposed to 6-day-old liquid cultures of W. anomalus, M. pulcherrima and S. cerevisiae for 48h showed 89%, 40%, and 32% reductions, respectively, in gray mold McKinney Index. Vapours of ethyl acetate, the main volatile organic compound of these yeasts, completely inhibited B. cinerea growth at 8.97mg/cm3, and suppressed gray mold on strawberry fruit at 0.718mg/cm3. The biocontrol activities of these yeasts can be ascribed to ethyl acetate, which can be used for control of postharvest gray mold of strawberry fruit.
•Yeast volatile organic compounds can reduce in vitro growth of decay-causing fungi.•Strawberry exposure to yeast producing volatile organic compounds reduces gray mold.•The main volatile organic compound of the three selected yeasts is ethyl acetate.•Ethyl acetate at 8.97mg/cm3 completely inhibits B. cinerea growth in the in vitro trials.•Ethyl acetate at 0.718mg/cm3 can control gray mold on strawberry fruit.
Lanthanide metal–organic frameworks (Ln‐MOFs) are promising for luminescence detection of volatile organic compound (VOC) vapors, but usually suffer from the silent or quenched Ln3+ emission. Herein, ...we report a new dual‐emissive Eu‐MOF composed of the coordinatively unsaturated Eu9 clusters that afford abundant open metal sites to form a confined “binding pocket” to facilitate the preconcentration and recognition of VOCs. Single‐crystal structural analyses reveal that specific analytes can replace the OH oscillators in the first coordination sphere of Eu3+ and form a unique hydrogen‐bonding second‐sphere adduct tying adjacent Eu9 clusters together to minimize their nonradiative vibrational decay. With the promoted Eu3+ luminescence, the MOF realizes real‐time in situ visual sensing of THF vapor (<1 s) and shows a quantitative ratiometric response to the vapor pressure with a limit of detection down to 17.33 Pa. Also, it represents a top‐performing ratiometric luminescent thermometer.
A dual‐emissive polynuclear Eu‐MOF enriched with abundant potential open metal sites was constructed. In terms of a novel recognition‐transduction protocol, this material realized real‐time in situ visual detection of THF vapor (<1 s) while showing a quantitative ratiometric response to vapor pressure with an ultralow limit of detection.
As a continuation of our previous review entitled “Vilsmeier‐Haack cyclisation as a facile synthetic route to thieno2,3‐bquinolines (Part I).” This review describes the methods of preparation and the ...chemical reactivity of thieno2,3‐bquinolines, which might show interesting biological activities.
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