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•Phase inversion and semi conducting TiO2 based TENG with enhanced performance.•The TENG shows 7 times and 10 times enhancement for voltage and current.•Fabricated TENG is ...multifunctional energy harvester.•Demonstration of TENG as VOC’s sensor with good selectivity and sensitivity.•Integration of TENG with Arduino for warning message and alarm to evacuate.
Mechanical energy harvesting using Triboelectric nanogenerator (TENG) based on the coupling of electrostatic induction and contact electrification is a cost-effective and straightforward process. TENG is well known for harnessing the waste energy at a large scale. Here, we demonstrated the fabrication of enhanced-performance TENG in contact-separation mode by utilizing the facile phase inversion process for only one triboactive layer. The phase inversion is a straightforward technique to achieve films with a porous structure and high crystallinity. The non-piezoelectric, semiconducting TiO2 microparticle acts as charge trapping sites attributed to their high dielectric constant. The PVDF-10-TiO2/CA TENG showed 7 times and 10 times enhancement for voltage and short circuit current compared to the PVDF-TiO2/CA TENG prepared without phase inversion process. Furthermore, the device is a multifunctional energy harvester i.e. it can harvest biomechanical as well as wind energy. Finally, we demonstrated the use of TENG device for volatile organic compounds (VOCs) sensing. The device exhibits good response with the change in concentration as well as total flow rate. The voltage decreases with the increase in the benzene concentration. The sensitivity of as fabricated sensor is 0.0035 V/ppm concerning concentration and 0.29176 V/sccm concerning total flow rate. The sensor was integrated with the Arduino Uno for automatic detection of benzene giving the alarm warning for the presence of benzene in the environment. This work extended the application of TENG in the field of VOCs sensing, design and concept which can be applied in the future for the detection of other VOCs in the environment.
Zhoushan is an island city with booming tourism and service industry, but also has many developed VOCs and/or NOX emission industries. It is necessary to carry out regional VOCs and O3 pollution ...control in Zhoushan as the only new area owns the provincial economic and social administration rights. Anthropogenic VOCs emission inventories were built based on emission factor method and main emission sources were identified according to the emission inventories. Then, localized VOCs source profiles were built based on in-site sampling and referring to other studies. Furthermore, ozone formation potentials (OFPs) profiles were built through VOCs source profiles and maximum incremental reactivity (MIR) theory. At last, the priority control analysis results showed that industrial processes, especially surface coating, are the key of VOCs and O3 control. Alkanes were the most emitted group, accounting for 58.67%, while aromatics contributed the most to ozone production accounting for 69.97% in total OFPs. n-butane, m/p-xylene, i-pentane, n-decane, toluene, propane, n-undecane, o-xylene, methyl cyclohexane and ethyl benzene were the top 10 VOC species that should be preferentially controlled for VOCs emission control. However, m/p-xylene, o-xylene, ethylene, n-butane, toluene, propene, 1,2,4-trimethyl benzene, 1,3,5-trimethyl benzene, ethyl benzene and 1,2,3-trimethyl benzene were the top 10 VOC species that required preferential control for O3 pollution control.
•VOCs emission inventory was built in Zhoushan in 2015.•Localized VOC source profiles were built by in-site sampling and from references.•Localized OFP profiles for sources were built from VOC source profiles and MIR.•Industrial processes, especially surface coating, are the key of VOCs and O3 control.•Alkanes were the most emitted group while aromatics contributed the most to OFPs.
Green leaf volatile production by plants Ameye, Maarten; Allmann, Silke; Verwaeren, Jan ...
The New phytologist,
November 2018, Letnik:
220, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Plants respond to stress by releasing biogenic volatile organic compounds (BVOCs). Green leaf volatiles (GLVs), which are abundantly produced across the plant kingdom, comprise an important group ...within the BVOCs. They can repel or attract herbivores and their natural enemies; and they can induce plant defences or prime plants for enhanced defence against herbivores and pathogens and can have direct toxic effects on bacteria and fungi. Unlike other volatiles, GLVs are released almost instantly upon mechanical damage and (a)biotic stress and could thus function as an immediate and informative signal for many organisms in the plant’s environment. We used a meta-analysis approach in which data from the literature on GLV production during biotic stress responses were compiled and interpreted.We identified that different types of attackers and feeding styles add a degree of complexity to the amount of emitted GLVs, compared with wounding alone. This meta-analysis illustrates that there is less variation in the GLV profile than we presumed, that pathogens induce more GLVs than insects and wounding, and that there are clear differences in GLV emission between monocots and dicots. Besides the meta-analysis, this review provides an update on recent insights into the perception and signalling of GLVs in plants.
Ambient ozone air pollution is one of the most important environmental challenges in China today, and it is particularly significant to identify pollution sources and formulate control strategies. In ...present study, we proposed a novel method of positive matrix factorization-SHapley Additive explanation (PMF-SHAP) for evaluating the impact of emission sources on ozone formation, which can quantify the main emission sources of ozone pollution. In this method, we first used the PMF model to identify the source of volatile organic compounds (VOCs), and then quantified various emission sources using a combination of machine learning (ML) models and the SHAP algorithm. The R2 of the optimal ML model in this method was as high as 0.96, indicating that the prediction performance was excellent. Furthermore, we explored the impact of different emission sources on ozone formation, and found that ozone formation in Shenzhen was more affected by VOCs, of which vehicle emission sources may have the greatest impact. Our results suggest that the appropriate combination of traditional models with ML models can well address environmental pollution problems. Moreover, the conclusions obtained based on the PMF-SHAP method were different from the traditional ozone formation potential (OFP) results, providing valuable clues for related mechanism studies.
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•A novel method is used to quantify various emission sources on O3 formation.•The results of PMF-SHAP provide valuable clues for related mechanism studies.•Vehicle emission sources in Shenzhen may have the greatest impact on O3 formation.
PtCu alloy leads to enhanced charge separation, and a dynamic balance of Cu1+,2+/Cu0 can be achieved under photothermocatalytic condition. The synergism of photothermocatalysis mainly comes from the ...acceleration of the Mars–van Krevelen redox cycle by photocatalysis and the enhancement of coke resistance by thermocatalysis.
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•PtCu/CeO2 exhibits effective photothermocatalytic mineralization of n-pentane.•PtCu promotes charge separation and reactive oxygen generation.•Dynamic balance of Cu1+,2+/Cu0 leads to high performance stability.•Photocatalysis accelerates the Mars–van Krevelen redox cycle.•Thermocatalysis enhances coke resistance.
The major challenges facing catalysts for mineralization of volatile organic compounds (VOCs) include poor photocatalytic efficiency, high cost of thermocatalytic oxidation, and low stability. Here, a highly active and stable PtCu/CeO2 ordered porous nanostructure catalyst was synthesized and efficiently applied in the instant mineralization of paraffinic VOCs under photothermocatalytic conditions. Optical and morphological characterization shows that low loadings of PtCu alloy clusters on CeO2 surfaces lead to enhanced light harvesting, improved charge separation, and increased capacity for reactive oxygen generation and then promote a dynamic balance of Cu1+,2+/Cu0 with high photothermocatalytic stability. Reaction kinetics calculations and carbon deposits investigation reveal that photothermocatalytic synergism mainly comes from the acceleration of the Mars–van Krevelen redox cycle by photocatalysis and the enhancement of coke resistance by thermocatalysis. The strategy here would provide insight into the design of highly effective catalysts, as well as in-depth understanding of the synergic mechanism of photothermocatalytic mineralization of refractory VOCs.
Zeolite-loaded noble metal catalysts have demonstrated excellent performance in addressing cold-start automotive exhaust NOx emissions and catalytic oxidation of VOCs applications. Pd and Pt are the ...most commonly used active metals in PNA and VOC catalysts, respectively. However, despite the same metal/zeolite composition, the efficient active sites for PNA and VOC catalysts have been viewed as mainly Pd2+ and Pt0, respectively, both of which are different from each other. As a result, various methods need to be applied to dope Pd and Pt in zeolitic support respectively for different usages. No matter which type of metal species is needed, the common requirement for both PNA and VOC catalysts is that the metal species should be highly dispersed in zeolite support and stay stable. The purpose of this paper is to review the progress of synthetic means of zeolite-coated noble metals (Pd, Pt, etc.) as effective PNA or VOC catalysts. To give a better understanding of the relationship between efficient metal species and the introduced methods, the species that contributed to the NOx adsorption (PNA) and VOCs deep catalytic oxidation were first summarized and compared. Then, based on the above discussion, the detailed construction strategies for different active sites in PNA and VOC catalysts, respectively, were elaborated in terms of synthetic routes, precursor selection, and zeolite carrier requirements. It is hoped that this will contribute to a better understanding of noble metal adsorption/catalysis in zeolites and provide promising strategies for the design of adsorption/catalysts with high activity, selectivity and stability.
The paper introduces noble metal species and active sites in PNA and VOCs catalysts. Then summarizes the impacts of precursors, zeolite properties, and metal introduction methods on active metal site construction in zeolites for these applications. Display omitted
•Pd2+ is the main active site for passive adsorption of NOx on Pd/zeolite.•Pt0 is the main active site for catalytic oxidation of VOCs on Pt/zeolite.•The form of precursor will affect the dispersion of noble metal species.•Zeolite structure, Si/Al ratio, acidity and hydrophobicity and so on will affect the dispersion of noble metals.•The preparation method will affect the distribution, dispersion and morphology of noble metals.
Exposure to cleaning products has been associated with harm to the respiratory system, neurotoxicity, harm to the reproductive system, and elevated risk of cancer, with greatest adverse impacts for ...workers exposed in an occupational setting. Social and consumer interest in cleaning products that are safer for health created a market category of “green” products defined here as products advertised as healthier, non-toxic, or free from harmful chemicals as well as products with a third-party certification for safety or environmental features. In the present study we examined the air quality impacts of cleaning products and air fresheners, measuring the number, concentrations, and emission factors of volatile organic compounds (VOCs) in an air chamber following product application. Across seven common product categories, 30 products were tested overall including 14 conventional, 9 identified as “green” with fragrance, and 7 identified as “green” and fragrance-free. A total of 530 unique VOCs were quantified with 205 additional VOCs detected below the limits of quantification. Of the quantifiable VOCs, 193 were considered hazardous according to either the California's Department of Toxic Substances Control Candidate Chemicals List or the European Chemical Agency's Classification and Labeling Inventory. The total concentration of VOCs and total emission factors across all products with detections ranged from below limits of detection to 18,708 μg/m3, 38,035 μg/g product and 3803 μg/application. Greater total concentration, total emission factors, and numbers of VOCs were generally observed in conventional cleaning products compared to products identified as “green”, particularly compared to fragrance-free products. A hazard index approach was utilized to assess relative risk from measured VOC emissions. The five products with the highest hazard indices were conventional products with emissions of 2-butoxyethanol, isopropanol, toluene and chloroform. Overall, this analysis suggests that the use of “green” cleaning products, especially fragrance-free products, may reduce exposure to VOC emissions.
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•Air chamber testing of 28 cleaning products and 2 air fresheners detected 530 VOCs.•The number and concentrations of VOCs were lower in “green” products.•Fragrance-free products had significantly lower numbers and concentrations of VOCs.•Exposure limits were used to calculate relative risk for each product.
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•VUV-PCO displayed higher toluene removal and mineralization rate than VUV photolysis.•O2 enabled greater enhancement for toluene degradation than H2O introduced.•Toluene and O3 was ...reduced as H2O participating in aerobic VUV based processes.•The intermediates were affected by the comprehensive effect of O2, H2O and catalyst.
Volatile organic compounds (VOCs) exists ubiquitously in chemical industries and were regarded as major contributors to air pollution, which should be strictly regulated. Vacuum ultraviolet irradiation coupled with photocatalytic oxidation (VUV-PCO) has been considered as an efficient approach to VOCs removal due to high-energy photons which could break down VOCs directly and be absorbed by photocatalysts to generate free radicals for further oxidation. However, the photochemical transformation mechanisms of VOCs have not been fully revealed. Herein, we systematically analyzed the intermediates using proton-transfer-reaction mass spectrometer (PTR-MS) to explore the transformation mechanisms of toluene degradation in VUV and VUV-PCO processes. VUV-PCO process displayed superior toluene degradation efficiency (50 %) and mineralization efficiency (65 %) compared with single VUV photolysis (35 %) and UV photocatalysis (5 %). TiO2 was deeply involved into CO2 generalization by amplifying the advantages of VUV system and further mineralizing the intermediates. In VUV and VUV-PCO processes, O2 participation changed the intermediates distribution by increasing multiple oxygenated products, while the introduction of water contributed to the formation and degradation of most intermediates. A possible degradation mechanism of toluene under VUV irradiation combined with TiO2 was proposed. This study provides a deep mechanistic insight into VOCs degradation by VUV-PCO process.
High concentration (>1000 ppm) volatile organic compounds (VOCs) is a serious threat and increasing technologies of catalytic oxidation have been developed to rapidly remove VOCs. However, single ...technology is usually restricted by the low removal efficiency and low mineralization rate. For example, photocatalysis (PC) exhibits high mineralization rate of VOCs, but the VOCs removal capacity is restricted (100–500 ppm). Plasma discharge catalysis (PDC) could remove high concentration VOCs, but the VOCs mineralization rate is low. In this work, we attempt to develop a coupled photo-plasma catalytic (PPC) technology to remove high concentration VOCs. We prepare WO3/TiO2 catalyst and select acetaldehyde as a representative of VOCs to evaluate the feasibility of coupled PPC. The PPC achieves degradation of 8025.49 ppm acetaldehyde and mineralization of 65.9 % in 30 min, which is superior to the PPC and PDC. The as-developed PPC technology is promising in the application of degrading high concentration VOCs.
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•Photo-plasma catalysis for the removal of high concentration of acetaldehyde.•Study of the synergistic effects of photocatalysis and plasma catalysis.•Synthesis, characterization and application of WO3/TiO2 composite catalysts.•Design of dielectric barrier discharge plasma reactor for acetaldehyde degradation in flowing systems.
The emission of gaseous pollutants from the combustion of fossil fuels is believed to be one of the most serious environmental challenges in the 21st century. Given the increasing demands of ...multipollutant control (MPC) via adsorption or catalysis technologies, such as NO x , volatile organic compounds (VOCs), heavy metals (Hg etc.), and ammonia, and considering investment costs and site space, the use of existing equipment, especially the selective catalytic reduction (SCR) system to convert pollutants into harmless or readily adsorbed substances, is one of the most practical approaches. Consequently, many efforts have been directed at achieving the simultaneous elimination of multipollutants in a SCR convertor, and this method has been widely used to mitigate the stationary emission of NO x . However, the development of active, selective, stable, and multifunctional catalysts/adsorbents suitable for large-scale commercialization remains challenging. Herein, we summarize recent works on the applications of SCR in MPC, describing the approaches of (i) SCR + VOCs oxidation, (ii) SCR + heavy metal control, and (iii) SCR + NH3 reduction to reveal that the efficiency of simultaneous elimination depends on catalyst composition and flue gas parameters. Furthermore, the synergistic promotional/inhibitory effects between SCR and VOCs/ammonia/heavy metal oxidations are shown to be the key to the feasibility of the reactions.
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