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1.
Chemosphere ; 237: 124462, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31394446

RESUMO

Particulate matter and volatile organic compounds have emerged as a prime environmental concern with increasing air pollution in metropolitan cities leading to lung and heart-related issues. This paper describes a facile and novel method for fabrication of polyester based air filter via surface coating with Sericin for imparting effective removal of particulate matter and volatile organic compounds. A simple dip-coating method followed by thermal fixation has been adopted to coat Sericin on the polyester fiber. The developed changes in surface functionality and morphology of the polyester fiber were confirmed by Attenuated total reflection Fourier-transform infrared spectroscopy and Field emission scanning electron microscopy analysis. The fabricated air filter was tested for removal of particulate matter (generated burning incense stick) and volatile organic compounds (generated vaporizing gasoline), in an indoor chamber. The Sericin coated filter was able to remove the PM2.5 and PM 10 (from 1000 µg/m3 level to 5 µg/m3 in a 6.28 m3 chamber) within 27 and 23 min of operation, respectively. The fabricated filter very effectively removed particulate matter for 2160 cycles with intermittent washing. The Sericin-coated air filter also proved very effective for removal of volatile organic compounds (Benzene, Toluene, Ethylbenzene and Xylene) from an indoor chamber at a varying initial concentration of 100-1000 µg/m3. The adsorption behavior was described by Langmuir-Freundlich (sips) isotherm and pseudo-first order kinetics with minimal error. The maximum adsorption capacity (mg/g) obtained with Sips Isotherm fitting followed the order Xylene (6.97)>Ethyl Benzene (5.68)> Toluene (5.35) >Benzene (4.78).


Assuntos
Filtros de Ar , Poluição do Ar em Ambientes Fechados , Material Particulado/isolamento & purificação , Sericinas/química , Compostos Orgânicos Voláteis/isolamento & purificação , Adsorção , Poluentes Atmosféricos/análise , Poluentes Atmosféricos/isolamento & purificação , Benzeno/análise , Benzeno/isolamento & purificação , Derivados de Benzeno/isolamento & purificação , Gasolina/análise , Microscopia Eletrônica de Varredura , Material Particulado/análise , Poliésteres/química , Espectroscopia de Infravermelho com Transformada de Fourier , Tolueno/análise , Compostos Orgânicos Voláteis/análise , Xilenos/análise , Xilenos/isolamento & purificação
2.
Phys Chem Chem Phys ; 21(35): 19226-19233, 2019 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-31441492

RESUMO

As one of the main air pollutants, nitrogen oxides (NOx) have serious effects on human health and the environment. In our previous study, we found that Mn-MOF-74 shows excellent catalytic performance for the selective catalytic reduction (SCR) reaction with NH3 being the reductant (NH3-SCR) at low temperature. To obtain a further understanding of the NH3-SCR mechanism in Mn-MOF-74, in this paper, we investigated two important parts of the NH3-SCR process in Mn-MOF-74 using the density functional theory (DFT) method. On the one hand, the structural characteristics of two types of oxygen vacancies of Mn-MOF-74, namely carboxyl oxygen vacancies and hydroxyl oxygen vacancies, and their adsorption properties to reaction species were calculated. It was found that the oxygen vacancies not only activate the reaction species, but also promote the desorption of NO2 molecules from metal sites for the subsequent rapid SCR reactions. On the other hand, we studied the effect of H2O on the structural stability and catalytic performance of Mn-MOF-74. It was found that the interaction of Mn-O bonds was weakened by H2O. Therefore, the influence of H2O should be considered for the future design of MOF-based catalysts for the SCR process.


Assuntos
Teoria da Densidade Funcional , Estruturas Metalorgânicas/química , Oxigênio/química , Água/química , Poluentes Atmosféricos/química , Poluentes Atmosféricos/isolamento & purificação , Catálise , Óxidos de Nitrogênio/química , Óxidos de Nitrogênio/isolamento & purificação , Substâncias Redutoras/química
3.
Environ Sci Pollut Res Int ; 26(29): 29660-29668, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31402436

RESUMO

Alkali metal chlorides emitted from sintering flue gas are easily adsorbed on the surface of activated carbon (AC) in the purification process. In this paper, NaCl particles adsorbing onto AC were simulated by impregnation method, and the size and morphology of NaCl particles were similar to those of NaCl-PM10 emitted from sintering flue gas. With the adsorption of NaCl particles, 2-10-µm pores of AC were filled, and the specific surface area of AC decreased. But NaCl led to the increase of acidic functional groups on the surface of AC. When 0.75 wt% NaCl was adsorbed, it was beneficial for AC catalytic denitration (de-NOx), because the chemical reaction was strengthened by acidic functional groups, so it showed a certain promotion of de-NOx efficiency. As 1.5 wt% NaCl and 3 wt% NaCl were adsorbed, NaCl had an inhibitory effect on AC de-NOx, which was because the specific surface area of AC decreased, and the prevention of physical adsorption played a major role. As a result, the de-NOx efficiency of AC adsorbed with 3 wt% NaCl decreased from 40.59 to 23.02% at 150 °C. Therefore, the absorption of NaCl fine particles on AC should not exceed 0.75 wt%.


Assuntos
Poluentes Atmosféricos/química , Carvão Vegetal/química , Gases/química , Cloreto de Sódio/química , Adsorção , Poluentes Atmosféricos/isolamento & purificação , Catálise , Resíduos Industriais , Óxido Nítrico/química , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
4.
Sensors (Basel) ; 19(17)2019 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-31443346

RESUMO

Artefact conditions need to be continuously monitored to avoid degradation effects naturally caused by time and public exploitation in order to increase the value of cultural assets. In this way, the atmospheric analysis of both biological and chemical pollutants potentially present inside conservation environments represents valid support for the adoption of preventive conservation actions by evaluating periodically the presence of risk for the same artefacts. The aim of the present study was to analyze the fungal particles, potentially biodeteriogen, through aerobiological volumetric monitoring, particularly inside valuable historical, artistic, and cultural sites. Different exposition and conservation typologies of the artefacts with different flows of visitors were considered. The applied methodologies have furnished a reliable description of biological air pollution due to the presence of fungal spores-moreover, they have allowed for the prevention of risk situations and the measurement of their evolution in order to limit degradation processes. Through aerobiological monitoring, it was possible to provide important indications for interventions of prevention, conservation and restoration of cultural heritage in indoor environments.


Assuntos
Poluentes Atmosféricos/isolamento & purificação , Monitoramento Ambiental/métodos , Esporos Fúngicos/crescimento & desenvolvimento , Poluição do Ar/prevenção & controle , Fungos/crescimento & desenvolvimento , Humanos
5.
Sensors (Basel) ; 19(17)2019 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-31450808

RESUMO

Ammonia (NH3) emission is one of the major environmental issues in livestock farming. Gas measurements are required to study the emission process, to establish emission factors, and to assess the efficiency of emission reduction techniques. However, the current methods for acquiring reference measurements of NH3 are either high in cost or labor intensive. In this study, a cost-effective ammonia monitoring system (AMS) was constructed from a commercially-available gas analyzing module based on tunable diode laser absorption (TDLA) spectroscopy. To cope with the negative measurement biases caused by differing inlet pressures, a set of correction equations was formulated. Field validation of the AMS on NH3 measurement was conducted in a fattening pig barn, where the system was compared to a Fourier-transform infrared (FTIR) spectroscopy analyzer. Under two test conditions in a fattening pig barn, the absolute error of the AMS measurements with respect to the average obtained values between the AMS and the FTIR was respectively 0.66 and 0.08 ppmv, corresponding to 5.9% and 0.5% relative error. Potential sources of the measurement uncertainties in both the AMS and FTIR were discussed. The test results demonstrated that the AMS was capable of performing high-quality measurement with sub-ppm accuracy, making it a promising cost-effective tool for establishing NH3 emission factors and studying NH3 emission processes in pig houses.


Assuntos
Poluentes Atmosféricos/isolamento & purificação , Amônia/isolamento & purificação , Monitoramento Ambiental , Agricultura , Poluentes Atmosféricos/química , Amônia/química , Animais , Gado , Análise Espectral , Suínos
6.
Artigo em Inglês | MEDLINE | ID: mdl-31319616

RESUMO

This study examined the use of high dosages of ultraviolet germicidal irradiation (UVGI) (253.7 nm) to deal with various concentrations of air pollutants, such as formaldehyde (HCHO), total volatile organic compounds (TVOC), under various conditions of humidity. A number of irradiation methods were applied for various durations in field studies to examine the efficiency of removing HCHO, TVOC, bacteria, and fungi. The removal efficiency of air pollutants (HCHO and bacteria) through long-term exposure to UVGI appears to increase with time. The effects on TVOC and fungi concentration were insignificant in the first week; however, improvements were observed in the second week. No differences were observed regarding the removal of HCHO and TVOC among the various irradiation methods in this study; however significant differences were observed in the removal of bacteria and fungi.


Assuntos
Microbiologia do Ar , Poluentes Atmosféricos/isolamento & purificação , Poluição do Ar em Ambientes Fechados/prevenção & controle , Formaldeído/isolamento & purificação , Compostos Orgânicos Voláteis/isolamento & purificação , Aerossóis , Poluentes Atmosféricos/efeitos da radiação , Formaldeído/efeitos da radiação , Umidade , Fotólise , Raios Ultravioleta , Compostos Orgânicos Voláteis/efeitos da radiação
7.
BMC Biotechnol ; 19(1): 52, 2019 07 25.
Artigo em Inglês | MEDLINE | ID: mdl-31345193

RESUMO

BACKGROUND: Packing materials is a critical design consideration when employing biological reactor to treat malodorous gases. The acidification of packing bed usually results in a significant drop in the removal efficiency. In the present study, a biotrickling filter (BTF2) packed with plastic balls in the upper layer and with lava rocks in the bottom layer, was proposed to mitigate the acidification. RESULTS: Results showed that using combined packing materials efficiently enhanced the removal performance of BTF2 when compared with BTF1, which was packed with sole lava rocks. Removal efficiencies of more than 92.5% on four sulfur compounds were achieved in BTF2. Average pH value in its bottom packing bed was about 4.86, significantly higher than that in BTF1 (2.85). Sulfate and elemental sulfur were observed to accumulate more in BTF1 than in BTF2. Analysis of principal coordinate analysis proved that structure of microbial communities in BTF2 changed less after the shutdown but more when the initial pH value was set at 5.5. Network analysis of significant co-occurrence patterns based on the correlations between microbial taxa revealed that BTF2 harbored more diverse microorganisms involving in the bio-oxidation of sulfur compounds and had more complex interactions between microbial species. CONCLUSIONS: Results confirmed that using combined packing materials effectively improved conditions for the growth of microorganisms. The robustness of reactor against acidification, adverse temperature and gas supply shutdown was greatly enhanced. These provided a theoretical basis for using mixed packing materials to improve removal performance.


Assuntos
Filtros de Ar/microbiologia , Reatores Biológicos/microbiologia , Microbiota , Compostos de Enxofre/isolamento & purificação , Compostos de Enxofre/metabolismo , Poluentes Atmosféricos/isolamento & purificação , Poluentes Atmosféricos/metabolismo , Biodegradação Ambiental , Filtração/instrumentação , Filtração/métodos , Oxirredução
8.
Chemosphere ; 234: 388-394, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31228841

RESUMO

The main aim of this work is to study gas-phase toluene removal in one- and two-liquid phase biotrickling filters (O/TLP-BTF) and model the BTF performance using artificial neural networks (ANNs). The TLP-BTF was operated for 60 d in the presence of silicone oil at empty bed residence times (EBRTs) of 120, 60, and 45 s, respectively, and toluene concentrations in the range of 0.9-3.1 g m-3. A t-test analysis indicated that increasing the silicone oil volume ratio from 5 to 10% v/v, did not significantly improve the TLP-BTF performance (p-value = 0.65 > 0.05). The results from ANN modeling showed that toluene removal was more negatively affected by the inlet concentration (casual index, CI = -5.63) due to the kinetic limitation. The CI values for inlet concentration (+4.01) and liquid trickling rate (-2.45) indicated that the diffusion-limited regime controlled the removal process in the OLP-BTF.


Assuntos
Filtração/métodos , Óleos de Silicone , Tolueno/isolamento & purificação , Poluentes Atmosféricos/isolamento & purificação , Gases , Cinética , Óleos de Silicone/química , Óleos de Silicone/farmacologia
9.
Environ Sci Pollut Res Int ; 26(24): 24831-24839, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31240653

RESUMO

Adsorption is a typical method for air pollutant removal from flue gas. A CuS-modified active coke (CuS/AC) sorbent was developed to improve the elemental mercury removal efficiency from municipal solid waste incineration (MSWI) flue gas. The influences of the loading amount of CuS, reaction temperature, and flue gas components including O2, SO2, H2O, and HCl on Hg0 removal efficiency were investigated, respectively. The results showed that the mercury adsorption capacity of CuS/AC(20%) sorbent was about 7.17 mg/g with 50% breakthrough threshold, which is much higher than that of virgin active coke. The analysis of XPS indicated that HgS was the main species of mercury on spent CuS/AC, which implied that adsorption and oxidation were both included in Hg0 removal. S22- played a vital role in the oxidation of physically adsorbed Hg0. Meanwhile, the common components of MSWI flue gas exhibited no significant inhibition effect on Hg0 removal by CuS/AC sorbent. CuS/AC sorbent is a promising sorbent for the mercury removal from MSWI flue gas.


Assuntos
Poluentes Atmosféricos/isolamento & purificação , Coque , Cobre/química , Incineração , Mercúrio/isolamento & purificação , Adsorção , Poluentes Atmosféricos/química , Gases/química , Mercúrio/química , Compostos de Mercúrio/análise , Compostos de Mercúrio/isolamento & purificação , Oxirredução , Resíduos Sólidos , Enxofre/química , Dióxido de Enxofre/química , Temperatura Ambiente
10.
Eur J Pharm Sci ; 137: 104973, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31254644

RESUMO

Strict microbial control is required in pharmaceutical manufacturing facilities, for which environmental microbial monitoring is fundamental. Appropriate microbial control is based on understanding the abundance and community structure of the microbes in the target environment, but most microbes are not culturable by conventional methods. Here, we determined the bacterial abundance and assessed the environmental microbiome in a pharmaceutical manufacturing facility using rRNA gene-targeted quantitative PCR (qPCR) and high-throughput sequencing of rRNA gene fragments. A commercially available microbial particle counter was also used for real-time measurements. In the air of the first gowning room and the passageway of the facility, the microbial particle number determined by both the particle counter and qPCR was ca. 104/m3; the number of microbial particles was about 100 times the number of culturable bacteria. Thus, the measurement of microbes using the particle counter was accurate. In the second gowning room of the facility, managed by a HEPA filter, the number of particles in the air was dependent on human movement, and was below the detection limit around 10 min after movement. Bacteria of the phyla Proteobacteria, Firmicutes, and Actinobacteria were frequently detected in samples from the facility; these bacteria are constituents of the human microbiota. Among fungi, Aspergillus and Cladosporium were detected in the air, and Malassezia was dominant on the walls. Our results provide fundamental data for the evaluation and control of microbes in pharmaceutical and food industry facilities.


Assuntos
Poluentes Atmosféricos/isolamento & purificação , Bactérias/isolamento & purificação , Indústria Farmacêutica , Fungos/isolamento & purificação , Instalações Industriais e de Manufatura , Bactérias/genética , Monitoramento Ambiental , Fungos/genética , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , RNA Bacteriano/análise , RNA Ribossômico 16S/análise
11.
J Chromatogr A ; 1602: 74-82, 2019 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-31176481

RESUMO

The purpose of this study was to develop a new method for the sampling and analysis of naphthalene (Nap) and phenanthrene (Phe) in air. XAD-2 sorbent was prepared with polyaniline (PANI) to increase its adsorption area. Thus, 22-gauge needles were packed with XAD-2/PANI sorbent for the extraction of Nap and Phe, and sampling of the analytes of interest. The compounds were dynamically sampled from the headspace of the flask in laboratory and then analyzed using a gas chromatography (GC) device equipped with flame ionization detector (FID). The needle trap device (NTD) with the proposed sorbent was more sensitive and accurate than the NIOSH 5515 method. The results showed that the optimal temperature and time for the desorption of the analytes were 350 °C and 8 min, respectively. The analytical parameters such as carryover effect, breakthrough volume, and storage time were examined. The repeatability of the method was determined to be 9.4-13.5% for Nap and 7.1-15.7% for Phe. The limits of detection (LOD) for the analytes were in the range 0.002 - 0.09 ng L-1, and the limits of quantitation (LOQ) were in the range 0.01- 0.23 ng L-1. It was also found that the NTD packed with XAD-2/PANI sorbent was a sensitive and cost-effective method, and offered a high accuracy for the sampling and analysis of PAHs in air.


Assuntos
Poluentes Atmosféricos/análise , Compostos de Anilina/química , Técnicas de Química Analítica/instrumentação , Naftalenos/análise , Fenantrenos/análise , Adsorção , Poluentes Atmosféricos/isolamento & purificação , Cromatografia Gasosa , Ionização de Chama , Limite de Detecção , Agulhas , Hidrocarbonetos Policíclicos Aromáticos/análise , Temperatura Ambiente
12.
Environ Pollut ; 246: 932-944, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31159143

RESUMO

Urban green spaces have the potential to mitigate and regulate atmospheric pollution. However, existing studies have primarily focused on the adsorption effect of different plants on atmospheric particulate matter (PM), whereas the effect of green space on PM has not been adequately addressed. In this study, the effect of different urban green space structures and configurations on PM was investigated through the 3D computational fluid dynamics (CFD) model ENVI-met by treating the green space as a whole based on field monitoring, and at the same time, the regulatory effect of green space on PM was examined by integrating information about the forest stand, PM concentration, and meteorological factors. The results show that the green space primarily affected wind speed but had no significant effect on relative humidity, temperature, or wind direction (P > 0.05). The PM concentration was significantly positively correlated with the relative humidity (P < 0.01), significantly negatively correlated with temperature (P < 0.05), but not significantly correlated with wind speed and direction (P > 0.05). Comparison with the measured values reveals that the ENVI-met model well reflected the differences in PM concentrations between different green spaces and the effect of green space on PM. In different green space structures, the uniform-type structure performed rather poorly at purifying PM, the concave-shaped structure performed the best, and the purifying effectiveness of the incremental-type and convex-shaped structure of green space was higher in the rear region than in the front region; in contrast, the degressional-type green space structure was prone to cause aggregation of the PM in the middle region. Broadleaf and broadleaf mixed forests had a better purifying effectiveness on PM than did coniferous forests, mixed coniferous forests, and coniferous broadleaf mixed forests. The above results are of great significance for urban planning and maximizing the use of urban green space resources.


Assuntos
Poluentes Atmosféricos/análise , Simulação por Computador , Microclima , Modelos Teóricos , Material Particulado/análise , Poluentes Atmosféricos/isolamento & purificação , Planejamento de Cidades , Monitoramento Ambiental , Florestas , Conceitos Meteorológicos , Material Particulado/isolamento & purificação
13.
Environ Sci Pollut Res Int ; 26(20): 20908-20919, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31115812

RESUMO

Large amount of volatile organic compounds (VOCs) are emitted from industrial, mobile, and domestic sources, causing adverse effects on human health and environment. Among VOCs, toluene and isopropanol (IPA) are commonly used as solvent, soldering flux, and spray paint and their emissions need to be reduced. Several VOCs abatement technologies are available to reduce VOC emission and photocatalytic oxidation of VOC is regarded as a viable technique due to its advantage of utilizing solar energy. TiO2 has been investigated for its oxidation capability toward VOCs because of its good photocatalytic activity. However the utilization is limited to UV due to its wider bandgap; furthermore, its fast recombination rate of electron-hole pair reduces the oxidation rate of VOCs. Black-TiO2 and perovskite-type photocatalyst such as LaFeO3 can be applied to enhance photocatalytic activity due to narrower bandgap and longer electron-hole pair lifetime. In this study, black-TiO2 and LaFeO3 are prepared and investigated for their photocatalytic oxidation rates toward toluene and IPA. Results show that toluene removals achieved with black-TiO2 and LaFeO3 are 89% and 98% while IPA removals are 90% and 94%, respectively. Both photocatalysts show better photocatalytic activity than TiO2 and good absorption capability toward visible light. Graphical abstract.


Assuntos
2-Propanol/química , Poluentes Atmosféricos/química , Compostos de Cálcio/química , Óxidos/química , Titânio/química , Tolueno/química , 2-Propanol/isolamento & purificação , Poluentes Atmosféricos/isolamento & purificação , Catálise , Recuperação e Remediação Ambiental , Luz , Oxirredução , Processos Fotoquímicos , Tolueno/isolamento & purificação
14.
Environ Sci Pollut Res Int ; 26(16): 16195-16209, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30972683

RESUMO

CO2, SO2, and NO are the main components of flue gas and can cause serious environmental issues. Utilization of these compounds in oleaginous microalgae cultivation not only could reduce air pollution but could also produce feedstock for biodiesel production. However, the continuous input of SO2 and NO inhibits microalgal growth. In this study, the toxicity of simulated flue gas (15% CO2, 0.03% SO2, and 0.03% NO, balanced with N2) was reduced through automatic pH feedback control. Integrated lipid production and CO2 fixation with the removal of SO2 and NO was achieved. Using this technique, a lipid content of 38.0% DW was achieved in Chlorella pyrenoidosa XQ-20044. The lipid composition and fatty acid profile indicated that lipid production by C. pyrenoidosa XQ-20044 cultured with flue gas is suitable as a biodiesel feedstock; 81.2% of the total lipids were neutral lipids and 99.5% of the total fatty acids were C16 and C18. The ratio of saturated fatty acids to monounsaturated fatty acids in the microalgal lipid content was 74.5%. In addition, CO2, SO2, and NO from the simulated flue gas were fixed and converted to biomass and lipids with a removal efficiency of 95.9%, 100%, and 84.2%, respectively. Furthermore, the utilization efficiencies of CO2, SO2, and NO were equal to or very close to their removal efficiencies. These results provide a novel strategy for combining biodiesel production with biofixation of flue gas.


Assuntos
Biotecnologia/métodos , Chlorella/efeitos dos fármacos , Chlorella/metabolismo , Lipídeos/biossíntese , Poluentes Atmosféricos/química , Poluentes Atmosféricos/isolamento & purificação , Poluentes Atmosféricos/toxicidade , Biocombustíveis , Biomassa , Biotecnologia/instrumentação , Dióxido de Carbono/isolamento & purificação , Dióxido de Carbono/toxicidade , Chlorella/crescimento & desenvolvimento , Ácidos Graxos/análise , Ácidos Graxos/metabolismo , Concentração de Íons de Hidrogênio , Microalgas/efeitos dos fármacos , Microalgas/crescimento & desenvolvimento , Microalgas/metabolismo , Óxido Nítrico/isolamento & purificação , Óxido Nítrico/toxicidade , Dióxido de Enxofre/isolamento & purificação , Dióxido de Enxofre/toxicidade
15.
Environ Sci Pollut Res Int ; 26(13): 12851-12858, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30891698

RESUMO

Volatile organic compounds (VOCs) are of public concern due to their adverse health effects. Botanical air filtration is a promising technology for reducing indoor air contaminants, but the underlying mechanisms are not fully understood. This study assessed active botanical biofilters for their single-pass removal efficiency (SPRE) for benzene, ethyl acetate and ambient total volatile organic compounds (TVOCs), at concentrations of in situ relevance. Biofilters containing four plant species (Chlorophytum orchidastrum, Nematanthus glabra, Nephrolepis cordifolia 'duffii' and Schefflera arboricola) were compared to discern whether plant selection influenced VOC SPRE. Amongst all tested plant species, benzene SPREs were between 45.54 and 59.50%, with N. glabra the most efficient. The botanical biofilters removed 32.36-91.19% of ethyl acetate, with C. orchidastrum and S. arboricola recording significantly higher ethyl acetate SPREs than N. glabra and N. cordifolia. These findings thus indicate that plant type influences botanical biofilter VOC removal. It is proposed that ethyl acetate SPREs were dependent on hydrophilic adsorbent sites, with increasing root surface area, root diameter and root mass all associated with increasing ethyl acetate SPRE. The high benzene SPRE of N. glabra is likely due to the high wax content in its leaf cuticles. The SPREs for the relatively low levels of ambient TVOCs were consistent amongst plant species, providing no evidence to suggest that in situ TVOC removal is influenced by plant choice. Nonetheless, as inter-species differences do exist for some VOCs, botanical biofilters using a mixture of plants is proposed.


Assuntos
Poluentes Atmosféricos/isolamento & purificação , Plantas , Compostos Orgânicos Voláteis/isolamento & purificação , Acetatos/isolamento & purificação , Benzeno/isolamento & purificação , Biodegradação Ambiental , Folhas de Planta/química , Especificidade da Espécie
16.
Pediatr. aten. prim ; 21(81): 21-29, ene.-mar. 2019. tab, graf
Artigo em Espanhol | IBECS | ID: ibc-184524

RESUMO

Objetivo: estudiar la relación existente entre los niveles de contaminantes atmosféricos y los ingresos hospitalarios pediátricos totales y por patología respiratoria en particular. Pacientes y métodos: estudio ecológico en el cual la variable dependiente analizada han sido los ingresos pediátricos generales y aquellos por patología respiratoria, concretamente neumonías, crisis asmáticas y bronquiolitis, en un hospital del centro de Madrid durante seis años (2012-2017). Como variables independientes se estudiaron los valores promedio de contaminantes ambientales registrados en la ciudad de Madrid. Se calcularon coeficientes de correlación y regresión lineal múltiple. Se comparó el promedio de ingresos cuando los valores de dióxido de nitrógeno (NO2) eran superiores e inferiores a 40 µg/m3. Resultados: durante el periodo de tiempo estudiado se registraron 10 512 ingresos en Pediatría general, 5328 (50,68%) causados por procesos respiratorios. Se encontró una correlación entre los niveles de NO2, CO, benceno y los ingresos hospitalarios totales y respiratorios en todos los casos con un valor de p <0,0001. En la regresión lineal múltiple los ingresos totales se relacionaron con los niveles de NO2 positiva y negativamente con la temperatura, en relación con los ingresos respiratorios se incrementan con los niveles de NO2 y benceno y disminuyen con la temperatura. Se calculó que si los niveles de NO2 no hubieran superado en ningún mes los niveles de 40 µg/m3 se podrían haber evitado el 8,37% (IC 95: 7,77 a 8,98) de los ingresos totales y el 6,73% (IC 95: 6 a 7,52) de los ingresos respiratorios. Conclusiones: se encontró una relación entre los ingresos totales y por enfermedad respiratoria en la infancia y los niveles de contaminantes atmosféricos, especialmente NO2. La mejora de la calidad del aire podría evitar un porcentaje significativo de ingresos pediátricos y propiciarla debería ser tarea prioritaria para los pediatras


Objective: to assess the association between levels of airborne pollutants and paediatric hospital admissions, overall and due to respiratory problems. Patients and methods: we conducted an ecological study in which the dependent variables were the number of total paediatric hospital admissions and the number of paediatric admissions due to respiratory problems, specifically pneumonia, asthma exacerbations and bronchiolitis, in a hospital located in the centre of Madrid over a period of 6 years (2012-2017). The independent variables were the mean levels of air pollutants recorded in the city of Madrid. We calculated correlation coefficients and fit multiple linear regression models. We compared the average number of admissions when the levels of nitrogen (NO2) were above and below 40 µg/m3. Results: in the period under study, there were 10 512 admissions to the general paediatrics ward, of which 5328 (50.68%) were due to respiratory problems. We found a correlation between the levels of NO2, CO, and benzene and the number of overall admissions and respiratory admissions, in every instance with a p-value of less than 0.0001. The multiple linear regression analysis revealed that the number of overall admissions was associated with NO2 levels (positively) and temperature (negatively), while respiratory admissions were associated to NO2 and benzene levels (positively) and temperature (negatively). We estimated that if the levels of NO2 had stayed below 40 µg/m3 throughout the study period, 8.37% (95 CI: 7.77 to 8.98) of total admissions and 6.73% (95 CI: 6 to 7.52) of respiratory admissions could have been avoided. Conclusions: we found an association between the number of admissions, overall and for respiratory causes, in the paediatric age group and the levels of air pollutants, especially NO2. Improving air quality could prevent a significant proportion of paediatric hospital admissions, and promoting this change should be a priority for paediatricians


Assuntos
Humanos , Masculino , Feminino , Lactente , Pré-Escolar , Criança , Adolescente , Hospitalização/estatística & dados numéricos , Poluentes Atmosféricos/isolamento & purificação , Poluição do Ar/efeitos adversos , Doenças Respiratórias/epidemiologia , Tempo de Internação/estatística & dados numéricos , Estudos Ecológicos , Poluição Ambiental/efeitos adversos , Doenças Respiratórias/prevenção & controle
17.
Chemosphere ; 222: 732-741, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30738316

RESUMO

The removal of toxic hydrogen sulfide (H2S) from the air at pilot-scale with elemental sulfur recovery was evaluated using Fe-EDTA chelate as a single treatment at a pH of about 8.5. This was later combined with a compost biofiltration process for polishing the pre-treated air. Experiments were performed in a unique container system that allowed deploying either Fe-EDTA chelate or Fe-EDTA chelate/biofiltration treatment (hybrid system). The results showed the feasibility of H2S removal at concentrations between 200 and 5300 ppmv (H2S loading rates of 7-190 g m-3 h-1) present in fouled air. The Fe-EDTA chelate as a single treatment was able to remove nearly 99.99% of the H2S at inlet concentrations ≤ 2400 ppmv (107 g m-3 h-1), while the hybrid system archived undetectable outlet H2S concentrations (<1 ppmv) at inlet levels of 4000 and 5300 ppmv. At 5300 ppmv, the Fe-EDTA chelate process H2S removal efficiency decreased to 99.20% due to the limitation of oxygen mass transfer in the Fe(III) regeneration reaction. Under the previous conditions, the pH was required to be controlled by the addition of NaOH, due to the likely occurrence of undesirable parallel reactions. The elemental sulfur yield attained in the physicochemical module was 75-93% with around 80% recovered efficiently as a solid.


Assuntos
Recuperação e Remediação Ambiental/métodos , Compostos Férricos/farmacologia , Sulfeto de Hidrogênio/isolamento & purificação , Enxofre/isolamento & purificação , Poluentes Atmosféricos/isolamento & purificação , Ácido Edético/farmacologia , Quelantes de Ferro/farmacologia , Oxigênio , Projetos Piloto
18.
Artigo em Inglês | MEDLINE | ID: mdl-30193082

RESUMO

A full-scale biotrickling filter (BTF) treating acetone air emissions of wood-coating activities showed difficulties to achieve outlet concentrations lower than 125 mg C m-3, especially for high inlet concentrations and oscillating emissions. To solve this problem, a laboratory investigation on acetone removal was carried out simulating typical industrial conditions: discontinuous and variable inlet concentrations and intermittent spraying. The results were evaluated in terms of removal efficiency and outlet gas emission pattern. Industrial emissions and operational protocols were simulated: inlet load up to 70 g C m-3 h-1 during 2 cycles of 4 h per day and intermittent trickling of 15 min per hour. The outlet gas stream of the pollutant was affected by intermittent spraying, causing a fugitive emission of pollutant. Complete removal efficiency was obtained during non-spraying. Average removal efficiencies higher than 85% were obtained, showing the feasibility of BTF to treat acetone. The outlet gas stream showed a clear dependence on the pH of the trickling liquid, decreasing the removal at pH < 5.5. Thus, a proper control of alkalinity, with regular NaHCO3 addition, was required for successful operation. The laboratory findings were fruitfully transferred to the industry, and the removal of acetone by full-scale BTF was improved.


Assuntos
Acetona/isolamento & purificação , Filtros de Ar , Filtração , Emissões de Veículos , Poluentes Atmosféricos/isolamento & purificação , Reatores Biológicos , Desenho de Equipamento , Filtração/instrumentação , Filtração/métodos , Laboratórios , Transferência de Tecnologia , Emissões de Veículos/prevenção & controle , Compostos Orgânicos Voláteis/isolamento & purificação
19.
Environ Sci Pollut Res Int ; 26(2): 1606-1614, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30446912

RESUMO

This study focuses on the removal of C4H4S using DC corona discharge plasma. The influences of various factors such as C4H4S concentration (ppm), temperature (°C), O2 concentration (%), and dust concentration (mg/m3) on the conversion of C4H4S were studied. Furthermore, gaseous compositions were determined using Fourier transform infrared (FTIR) spectroscopy. Solid products, which were collected from earth and discharge electrodes, were analyzed using X-ray diffraction (XRD). The results showed that, under the condition of DC corona discharge plasma, C4H4S converted to CO, CO2, S, SO2, and SO42-, and that the conversion rate increased with the increase in specific input energy (SIE). The increase of O2 concentration led to further energy consumption that generated O3, which in turn decreased the conversion rate of C4H4S. The increase in temperature exhibited a positive influence on the conversion of C4H4S when the SIE was less than 268 J/L. However, above this value of SIE, the temperature affected the conversion of C4H4S negatively with the increase in SIE. When dust was introduced, the conversion of C4H4S was significantly improved and the yield of SO2 reduced due to the reaction which took place among C4H4S, SO2 and dust in the electric field. The results showed that the DC corona discharge plasma exhibited considerable potential to remove C4H4S, while dust contributed positively towards the disposal of C4H4S. Graphical abstract In this work, DC corona plasma was used to remove thiophene (C4H4S) from a dust-containing gas stream. The results showed that electron collision, oxidizability of radicals, and existence of O3 were the main causes of C4H4S decomposition. The electron collision effects, contents of radicals, O3, and the conversion rate of C4H4S were enhanced with the increase in SIE (specific input energy). The main products consisted of CO, CO2, SO2, and solid products. The solid products and dust moved to the earth electrode in the electric field.


Assuntos
Poluentes Atmosféricos/isolamento & purificação , Gases em Plasma/química , Tiofenos/isolamento & purificação , Poluentes Atmosféricos/química , Dióxido de Carbono/química , Monóxido de Carbono/química , Poeira , Oxigênio/química , Espectroscopia de Infravermelho com Transformada de Fourier , Sulfatos/química , Dióxido de Enxofre/química , Temperatura Ambiente , Tiofenos/química , Difração de Raios X
20.
Environ Sci Pollut Res Int ; 26(4): 3991-3999, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30552613

RESUMO

With raising awareness of gaseous air pollutants and their harmful impact, adsorption is considered one of the most prominent techniques for gaseous emissions control. The usage of polyaniline as a gas adsorbent is an innovative idea. This work aims to compare the efficacy of synthesized polyaniline nanotubes (PANT) as a novel adsorbent towards inorganic gases (ammonia NH3) and volatile organic compounds (toluene vapor). PANT was prepared via a sol-gel preparation technique. The molecular structure of prepared PANT was characterized by Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The morphological structure was confirmed using transmission electron microscopy (TEM) and scanning electron microscope (SEM). The PANT adsorbent surface area was determined using Brunner Emmett Teller (BET). Dynamic behavior of simulated feed gas mixture of NH3 and toluene in air were examined using a fixed bed adsorption arrangement. The same adsorption conditions (inlet concentration, gas mixture feed flow rate, and a fixed amount of adsorbent) were applied for both NH3 and toluene adsorption test. The NH3 and toluene removal efficiencies were 100% and 96% respectively. Consequently, PANT is an auspicious adsorbent that can be utilized to control the indoor and outdoor gaseous air emissions. Graphical Abstracts ᅟ.


Assuntos
Poluentes Atmosféricos/química , Amônia/química , Compostos de Anilina/química , Tolueno/química , Adsorção , Poluentes Atmosféricos/isolamento & purificação , Amônia/isolamento & purificação , Gases/química , Ácido Clorídrico/química , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Estrutura Molecular , Nanotubos/química , Espectroscopia de Infravermelho com Transformada de Fourier , Tolueno/isolamento & purificação , Difração de Raios X
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