Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 11.056
Filtrar
1.
J Environ Manage ; 261: 110169, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32148261

RESUMO

The bioremediation of an oily sludge (321 ± 30 mg of polycyclic aromatic hydrocarbons/kgDRY SLUDGE and 13420 ± 1300 mg of aliphatic hydrocarbons/kgDRY SLUDGE) by mixture with contaminated soil (23 ± 2 mg of polycyclic aromatic hydrocarbons/kgDRY SOIL and 98 ± 10 mg of aliphatic hydrocarbons/kgDRY SOIL) was studied. Furthermore, the effect of oxidative pretreatments (persulfate and permanganate) on the performance of the global process was examined. The treatments reached contamination levels lower than the original residues, indicating the presence of synergic processes between a highly contaminated sludge and soil with a selected hydrocarbon-degrading community. Pretreatment with permanganate significantly improved biodegradation, possibly due to the increase in bioavailability and biodegradability of petroleum hydrocarbons. Two months of incubation was enough to reach the complete elimination of polycyclic aromatic hydrocarbons and 92% elimination of aliphatic hydrocarbons. Monitoring using five parameters (concentration of total petroleum hydrocarbons, total cultivable heterotrophic bacteria count, lipase and dehydrogenase activities, and polycyclic aromatic hydrocarbon-degrading bacteria count) as an approach for a preliminary scanning of the effectiveness of a treatment is proposed based on principal components analysis.


Assuntos
Petróleo , Hidrocarbonetos Policíclicos Aromáticos , Poluentes do Solo , Biodegradação Ambiental , Hidrocarbonetos , Compostos de Manganês , Óxidos , Esgotos , Solo , Microbiologia do Solo
2.
J Environ Manage ; 261: 110229, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32148299

RESUMO

Technologies for water recycling within oil refineries have been gaining interest at an extensive rate due to the large volume of wastewater generated, high dependency of water and the progressive scarcity of this valuable resource. Phenols are part of a specific class of organic pollutants that have been contributing to a low-quality effluent in oil refineries due to their hazardous nature and strict environmental legislation associated. The reuse of stripped sour water within refineries is often blocked due to its rich phenolic content. This study evaluates the retention of phenols in refinery wastewater through reverse osmosis (RO) at its major source of emission, for water reclamation. The RO membrane selected exhibited rejections of up to 98% of phenols and 99% of both chemical oxygen demand (COD) and total organic carbon (TOC). Permeate quality remained intact despite flux decline caused by phenolic and hydrocarbon adsorption when the oil content, in the feed, reached 771 ppm. The effluent's low conductivity due to lack of salts led to minor osmotic pressure differences (less than 2.5 bar at a volume concentration factor of 3), therefore, showing appealing performances of reverse osmosis filtration. Characterization of all permeates obtained from cross-flow filtration experiments showed COD levels in line with water reuse quality standards for make-up water in cooling processes.


Assuntos
Eliminação de Resíduos Líquidos , Purificação da Água , Filtração , Hidrocarbonetos , Membranas Artificiais , Osmose , Pressão Osmótica , Fenóis , Águas Residuárias
3.
Medicine (Baltimore) ; 99(12): e19519, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32195954

RESUMO

BACKGROUND: The purposes of this study were to examine the feasibility of using the MyotonPRO digital palpation device in measuring the passive stiffness of gastrocnemius muscle belly and Achilles tendon; to determine between-days test-retest reliability of MyotonPRO; and to evaluate the acute effect of paraffin therapy on stiffness measurements in healthy participants. METHODS: It is a randomized controlled trial. Twenty healthy participants (male, n = 10; female, n = 10; total, n = 20) were recruited to evaluate the passive stiffness of gastrocnemius muscle belly and Achilles tendon. Dominant and nondominant legs were randomly divided into an experimental side (20 cases) and a control side (20 cases). The experimental side received 20 minutes of paraffin therapy. RESULTS: The stiffness of muscle and tendon in the experimental side decreased significantly after paraffin therapy (P < .01), whereas no significant differences in stiffness measurements were found in the control side (P > .05). The passive stiffness of muscle and tendon was positively correlated with the ankle from 30° plantar flexion to10° dorsiflexion for dominant legs. Between-days test-retest reliability in stiffness measurements was high or very high (ICCs were above 0.737). CONCLUSION: Paraffin therapy induces a decrease in the passive stiffness of gastrocnemius muscle belly and Achilles tendon. Furthermore, the MyotonPRO can reliably determine stiffness measurements.


Assuntos
Tendão do Calcâneo/efeitos dos fármacos , Hidrocarbonetos/uso terapêutico , Tono Muscular/efeitos dos fármacos , Músculo Esquelético/efeitos dos fármacos , Parafina/uso terapêutico , Tendão do Calcâneo/fisiopatologia , Adolescente , Adulto , Articulação do Tornozelo/fisiologia , Feminino , Humanos , Masculino , Músculo Esquelético/fisiopatologia , Modalidades de Fisioterapia/tendências , Amplitude de Movimento Articular/fisiologia , Reprodutibilidade dos Testes , Adulto Jovem
4.
J Environ Manage ; 261: 110112, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32001431

RESUMO

The current energy demand and diminishing conventional fuels have forced researchers to find an alternative source of energy. Waste to energy is the current trend for converting waste materials (plastic waste) into valuable fuels. This article mainly discussed the detailed characterization of the pyrolytic products, their comparative analysis and the reaction mechanism at varying operating temperature. This article is a successor of part 1, which primarily focused on the characterization of different waste plastics, their TG analysis, the effect of reactor temperature on yield analysis in a batch reactor and their detailed degradation mechanism. Furthermore, the results presented in this article report the characterization of products at three processing temperatures of 450, 500 and 550 °C. The pyrolytic oils from all wastes excluding PS show a very low density ranging from 0.71 to 0.76 kg/m3, whereas PS pyrolytic density is reported between 0.86 and 0.88 kg/m3. The viscosity of oils increases with an increase in the processing temperature and is similar to the conventional fuels. The FTIR analysis of the products (oil & gases) obtained from HDPE, PP and mixed plastic waste (MIX) shows a large presence of alkanes and a higher presence of aromatics. PS analysis reported a large presence of aromatics (~75%). The GC-MS analysis of all pyrolytic oils from waste plastics, simulated wastes (virgin plastics) and distilled fraction of MIX pyrolysis oil is compared. The GC analysis of non-condensable gases at all processing temperature reports that MIX produce the maximum H2; HDPE, PS and MIX produces a high amounts of CH4 too. The formation of lower hydrocarbons (C5-C12) in pyrolysis oil shows a trend as MIX > PP > PS > HDPE, while for the heavier hydrocarbons (>C19) it is HDPE > PP > PS > MIX. The potential of the utilization of these products has been discussed in different sectors for future research.


Assuntos
Plásticos , Resíduos , Hidrocarbonetos , Óleos , Temperatura Ambiente
5.
Mar Pollut Bull ; 151: 110804, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32056599

RESUMO

Here, we report results from a 15-day mesocosm experiment examining changes in estimated oil equivalents (EOEs), n-alkanes (n-C10 to n-C35), polycyclic aromatic hydrocarbons (PAHs) and petroleum biomarkers. Water accommodated fractions (WAF) of oil and diluted chemically enhanced WAF (DCEWAF) were prepared and concentrations of oil residues determined on day 0, 3 and 15, respectively. Significant removals of n-alkane and PAHs were observed starting from day 3. The n-C17/pristane and n-C18/phytane ratios suggested that the n-alkane removal was due to biodegradation in the mesocosms. The ratios of C2-dibenzothiophenes/C2-phenanthrenes (D2/P2) and C3-dibenzothiophenes/C3-phenanthrenes (D3/P3) were found to be stable through the experiment. DCEWAF treatment had longer half-lives for most n-alkanes but shorter half-lives for most PAHs than the WAF treatment. Most petroleum biomarkers were stable throughout the experiment. However, depletion of TAS (tricyclic aromatic steroids) was observed on day 15 of DCEWAF treatment.


Assuntos
Ecossistema , Poluição por Petróleo , Petróleo , Tensoativos , Poluentes Químicos da Água , Hidrocarbonetos , Hidrocarbonetos Policíclicos Aromáticos
6.
Environ Monit Assess ; 192(2): 115, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31940086

RESUMO

Nowadays, the growing concern about the environmental problems affecting the subsoil has focussed efforts on the detection and characterization of contaminated sites through geophysical prospecting methods. In the present study, a case of a contaminated site by hydrocarbons and their study by means of time domain-induced polarization tomography is presented. The response in chargeability of porous media due to this kind of pollutant allows its delimitation using this method. However, one of the limitations for the application of this technique is the presence of lithologies that contain electro-metallic salts. These salts can produce anomalies of chargeability and mask those due to nonaqueous phase liquids. The studies were conducted in an area contaminated by fuel leaks from supply tanks within a train maintenance facility. Those leaks occurred while the tanks were in use, but since their dismantling, the leak stopped. The geology of the area presented strong heterogeneities and the access was limited by train tracks. In order to locate and characterize the contaminant plume, measurements of resistivity and chargeability were carried out. A grid of monitoring wells in this area was also available from which information about free-phase pollutants was obtained, and a new drilling was carried out to verify an unexpected anomaly. The results obtained show that the location of the plume by the geophysical techniques employed can lead to ambiguity, as an anomaly that does not correspond to contaminated areas appeared but to the presence of clays rich in electro-metallic components such as Mg, Fe, Mn and Al.


Assuntos
Monitoramento Ambiental/métodos , Hidrocarbonetos/química , Poluentes do Solo/química , Geologia , Hidrocarbonetos/análise , Metais , Solo , Poluentes do Solo/análise , Tomografia
7.
Environ Sci Technol ; 54(4): 2500-2509, 2020 02 18.
Artigo em Inglês | MEDLINE | ID: mdl-31986023

RESUMO

Bioremediation is a low-cost approach for crude oil spill remediation, but it is often limited by electron acceptor availability. In addition, the biodegradation products of crude oil contaminants are complex, and transformation pathways are difficult to decipher. This study demonstrates that bioelectrochemical systems (BESs) can be effective in crude oil degradation by integrating biological and electrochemical pathways, and more importantly, it provides the first understanding on the daughter products of bioelectrochemical hydrocarbon degradation. Using electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and two-dimensional gas chromatography (GC × GC), the results showed that the active BES reactor improved the total petroleum hydrocarbon (TPH) degradation by ∼70% than open circuit control reactors. After separating the daughter products into nine fractions (MA1-MA9) according to the molecular weight (m/z 200-1000) by modified aminopropyl silica (MAPS) fractionation, we found that active BES remediation resulted in 50% more polar, oxygen-containing naphthenic (NAP) acids. The MA4 fraction (centered at ∼550 Da) increased by 47%, and MA5 and MA7 fractions with higher molucular weight increased by a maximum of ∼7- and 9-fold, respectively. These results are in accordance with the variation of bulk elemental compositions in O2 species, where daughter transformation products doubled relative to parent oil extract. The contribution of newly generated NAP acids was mainly from higher-order oxygen species (O5-O6) with increased hydrophobicity in conjunction with a decreased abundance in lower-order oxygen species (O1). Overall, the study suggests that n-alkane degradation occurred via ß-oxidation to oxygenated transformation products with lower molecular weight, such as n-alcohols in O1 class and subsequently to n-fatty acids in O2 class.


Assuntos
Poluição por Petróleo , Petróleo , Biodegradação Ambiental , Hidrocarbonetos , Espectrometria de Massas , Solo
8.
Acta Crystallogr C Struct Chem ; 76(Pt 1): 87-92, 2020 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-31919311

RESUMO

1,3-Enyne structural motifs are versatile building blocks in organic synthesis and occur widely in various natural products with many of them being highly active as cytotoxic macrolides and antitumour antibiotics. This article presents the crystal structure of three 1,1,4-triphenyl-substituted 1,3-enynes, viz. 4-(2-methylphenyl)-1,1-diphenylbut-1-en-3-yne, C23H18 (1), 4-(2-methoxyphenyl)-1,1-diphenylbut-1-en-3-yne, C23H18O (2), and 4-(4-nitrophenyl)-1,1-diphenylbut-1-en-3-yne, C22H15NO2 (3). The benzene ring at position 4 of the but-1-en-3-yne group bears a weakly activating methyl group in compound 1, a moderately activating methoxy group in 2 and a strongly deactivating nitro group in 3. The crystal structures of 1 and 3 both have monoclinic symmetry, while that of 2 is orthorhombic, and all of them have one molecule in the asymmetric unit. All three compounds were investigated for their antibacterial and antifungal activities. Interestingly, enyne 2 is the only compound tested that inhibited the growth of Aspergillus niger.


Assuntos
Cristalografia por Raios X/métodos , Hidrocarbonetos/química , Antibacterianos/química , Antifúngicos/química , Estrutura Molecular
9.
Environ Sci Technol ; 54(3): 1522-1532, 2020 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-31906621

RESUMO

The objective of this study was to advance analytical methods for detecting oil sands process-affected water (OSPW) seepage from mining containments and discriminating any such seepage from the natural bitumen background in groundwaters influenced by the Alberta McMurray formation. Improved sampling methods and quantitative analyses of two groups of monoaromatic acids were employed to analyze OSPW and bitumen-affected natural background groundwaters for source discrimination. Both groups of monoaromatic acids showed significant enrichment in OSPW, while ratios of O2/O4 containing heteroatomic ion classes of acid extractable organics (AEOs) did not exhibit diagnostic differences. Evaluating the monoaromatic acids to track a known plume of OSPW-affected groundwater confirmed their diagnostic abilities. A secondary objective was to assess anthropogenically derived artificial sweeteners and per- and polyfluoroalkyl substances (PFAS) as potential tracers for OSPW. Despite the discovery of acesulfame and PFAS in most OSPW samples, trace levels in groundwaters influenced by general anthropogenic activities preclude them as individual robust tracers. However, their inclusion with the other metrics employed in this study served to augment the tiered, weight of evidence methodology developed. This methodology was then used to confirm earlier findings of OSPW migrations into groundwater reaching the Athabasca River system adjacent to the reclaimed pond at Tar Island Dyke.


Assuntos
Água Subterrânea , Poluentes Químicos da Água , Alberta , Ácidos Carboxílicos , Hidrocarbonetos , Campos de Petróleo e Gás , Areia
10.
Sci Total Environ ; 713: 136331, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-31955070

RESUMO

An adequate amount of nutrients is required to enable biodegradation of refractory hydrocarbons in petroleum-contaminated soil. In this study, a microcosm experiment was conducted using a drip fertigation method for petroleum-contaminated soil remediation. Nitrogen and phosphorus were homogeneously and periodically sprayed into a historically contaminated soil using a modified horticultural drip irrigation device. Various petroleum hydrocarbon fraction contents were then determined by gravimetry and gas chromatography (GC), and changes in the soil microbial community were analyzed by high throughput sequencing. After 90 days of remediation, the removal efficiencies of total petroleum hydrocarbon (TPH), saturates, aromatics, C7-C30 n-alkanes, and 16 PAHs were respectively enhanced by 21.5%, 25.5%, 12.4%, 10.4%, and 19.6% compared with the use of a single nutrient amendment application. The high throughput sequencing result showed that obvious changes had occurred in the soil microbial community compositions during drip fertigation; however, fungi were more sensitive to drip fertigation than bacteria. The resulting predominant bacterial and fungal genera were Dietzia, Nocardioides, Mycobacterium, Sphaerobacter, Leifsonia, and Aspergillus, Scolecobasidium, and Fusarium, respectively. Remediating polluted soils by regular fertigation ensures the automatic addition of even amounts of nutrients, which achieves high refractory hydrocarbon removal efficiencies. It is expected that this method can be applied in the in-situ remediation of petroleum-contaminated soil on a large scale.


Assuntos
Microbiota , Biodegradação Ambiental , Hidrocarbonetos , Nutrientes , Petróleo , Solo , Microbiologia do Solo , Poluentes do Solo
11.
J Environ Manage ; 258: 110013, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31929055

RESUMO

The effect of competition between isolated petroleum-degrading bacteria (PDB) and indigenous compost microorganisms (ICM) on the efficiency of composting process in bioremediation of petroleum waste sludge (PWS) was investigated. After isolating two native PDB (Acinetobacter radioresistens strain KA5 and Enterobacter hormaechei strain KA6) from PWS, their ability for growth and crude oil degradation was examined in the mineral-based culture (MBC). Then, the PDB isolate were inoculated into the composting experiments and operated for 12 weeks. The results showed that the PDB degraded 21.65-68.73% of crude oil (1-5%) in the MBC after 7 days. The PDB removed 84.30% of total petroleum hydrocarbon (TPHs) in the composting bioreactor containing the initial TPH level of 20 g kg-1. Removal of petroleum hydrocarbons (PHCs) in the composting experiments proceeded according to the first-order kinetics. The computed values of degradation rate constants and half-lives showed a better performance of the PDB than ICM for TPHs removal. This finding suggests that simultaneous application of the PDB and ICM in the composting reactors resulted in a decline in the effectiveness of the PDB which is due to competition between them. The study also verified that the capability of PDB in degrading PHCs can be successfully scaled-up from MBC to composting process.


Assuntos
Compostagem , Petróleo , Poluentes do Solo , Biodegradação Ambiental , Hidrocarbonetos , Minerais , Esgotos , Microbiologia do Solo
12.
J Basic Microbiol ; 60(1): 14-21, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31696960

RESUMO

Gordoniae are one of the most promising hydrocarbon-oxidizing actinobacteria. Here we present the genome sequence analysis of thermotolerant strain Gordonia sp. 1D isolated from oil-refinery soil. It is capable of alkane consumption and biosurfactant production at temperatures of up to 50°C. Gordonia sp. 1D demonstrates maximum biosurfactant production when grown on hexadecane, and at 40°C it was slightly higher than at 27°C: 35 and 39 mN/m, respectively. For the first time, it was experimentally confirmed that the carbohydrate component of extracellular biosurfactants produced by strain 1D is trehalose. In addition, genes for the production of trehalose lipid biosurfactants were identified. The genetic determinants for two different pathways for trehalose synthesis were found. The strain carries genes otsA and otsB involved in de novo trehalose biosynthesis. Moreover, the genes treY and treZ responsible for trehalose biosynthesis from maltooligosaccharides and starch or glycogen were identified.


Assuntos
Genoma Bacteriano/genética , Gordonia (Bactéria)/genética , Gordonia (Bactéria)/metabolismo , Trealose/metabolismo , Genes Bacterianos , Glicolipídeos/química , Glicolipídeos/metabolismo , Gordonia (Bactéria)/classificação , Hidrocarbonetos/metabolismo , Petróleo/microbiologia , Filogenia , Microbiologia do Solo , Tensoativos/química , Tensoativos/metabolismo , Temperatura Ambiente
13.
Environ Pollut ; 256: 113416, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31677871

RESUMO

Marine oil spill often causes contamination of drinking water sources in coastal areas. As the use of oil dispersants has become one of the main practices in remediation of oil spill, the effect of oil dispersants on the treatment effectiveness remains unexplored. Specifically, little is known on the removal of dispersed oil from contaminated water using conventional adsorbents. This study investigated sorption behavior of three prototype activated charcoals (ACs) of different particle sizes (4-12, 12-20 and 100 mesh) for removal of dispersed oil hydrocarbons, and effects of two model oil dispersants (Corexit EC9500A and Corexit EC9527A). The oil content was measured as n-alkanes, polycyclic aromatic hydrocarbons (PAHs), and total petroleum hydrocarbons (TPHs). Characterization results showed that the smallest AC (PAC100) offered the highest BET surface area of 889 m2/g and pore volume of 0.95 cm3/g (pHPZC = 6.1). Sorption kinetic data revealed that all three ACs can efficiently adsorb Corexit EC9500A and oil dispersed by the two dispersants (DWAO-I and DWAO-II), and the adsorption capacity followed the trend: PAC100 > GAC12 × 20 > GAC4 × 12. Sorption isotherms confirmed PAC100 showed the highest adsorption capacity for dispersed oil in DWAO-I with a Freundlich KF value of 10.90 mg/g∙(L/mg)1/n (n = 1.38). Furthermore, the presence of Corexit EC9500A showed two contrasting effects on the oil sorption, i.e., adsolubilization and solubilization depending on the dispersant concentration. Increasing solution pH from 6.0 to 9.0 and salinity from 2 to 8 wt% showed only modest effect on the sorption. The results are useful for effective treatment of dispersed oil in contaminated water and for understanding roles of oil dispersants.


Assuntos
Hidrocarbonetos/química , Poluição por Petróleo , Poluentes Químicos da Água/química , Adsorção , Alcanos , Carvão Vegetal/química , Cinética , Petróleo/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Hidrocarbonetos Policíclicos Aromáticos/química , Salinidade , Água do Mar/química , Tensoativos/química , Poluentes Químicos da Água/análise
14.
Bioresour Technol ; 297: 122385, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31761625

RESUMO

This work mainly studied B. braunii adapted to different CO2 concentrations with cobalt enrichment, and developed a process for CO2 capture, hydrocarbon production and cobalt removal. The results showed that B. braunii favored rapid growth at 5.0% (v/v) CO2, and the highest biomass was 1.89 g.L-1 with 4.5 mg.L-1 of cobalt. Hydrocarbon productivity in high concentration CO2 (5.0% and 10.0%) with cobalt enrichment was higher than that in Chu 13 medium. The change in cobalt removal efficiency mainly corresponded to the growth of B. braunii. The LCE of B. braunii in cobalt-rich with high CO2 concentration (5.0% and 10.0%) was 15.7%, and 14.9%, respectively, which was higher than that in normal medium. CO2 fixation rates were also higher in cobalt enrichment coupled with high CO2 concentration. This study not only provides ideas for the removal of toxic metal cobalt, but also has great potential for CO2 biofixation.


Assuntos
Dióxido de Carbono , Clorófitas , Biomassa , Cobalto , Hidrocarbonetos
15.
J Chem Ecol ; 46(1): 40-47, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31808076

RESUMO

Cuticular hydrocarbons (CHCs) are the main components of the epicuticular wax layer that in many insects functions as a barrier against desiccation. CHCs also play many other roles, including serving as sex pheromones, kairomones, primer pheromones, and colony-, caste-, species- and sex-recognition signals. In insects, CHC profiles can vary depending upon age, species, sex, and strain. Understanding factors associated with variation in hydrocarbon profiles is important for identifying potential vulnerabilities relating to pest ecology and life histories and for developing tools for pest monitoring and management strategies. In this study, we assessed potential sources of variation in CHC profiles in the navel orangeworm Amyelois transitella (Walker) (Lepidoptera: Pyralidae), an economically important pest of nut crops in California. Using coupled gas chromatography-mass spectrometry, we characterized and compared CHC profiles between adults of pyrethroid-resistant (R347) and susceptible (ALMOND) strains. We further compared CHC profiles from adults differing in age (1, 3, 5, and 7 d post-eclosion) and sex. Hydrocarbon profiles comprised 47 different CHCs in detectable quantities that ranged from C17 to C43 in chain length and included straight-chain alkanes and a variety of mono-, di-, and tri-methylalkanes. Adults from resistant populations had greater quantities of CHCs in total than those from susceptible strains, but relative quantities of individual components were similar. The six most abundant compounds were n-pentacosane, n-heptacosane, n-nonacosane, n-hentriacontane, 11,25 + 13,23 + 15,21-dimethylpentatriacontane, and 13,23 + 11,25 + 9,17-dimethylheptatriacontane. Post-eclosion, total CHCs increased with adult age, with males producing greater quantities than females at all ages. Our results show that CHC profiles vary depending on age, sex, and strain and suggest that CHC profiles may be useful as biomarkers to differentiate between insecticide- resistant and susceptible populations.


Assuntos
Hidrocarbonetos/química , Mariposas/química , Animais , Cromatografia Líquida de Alta Pressão , Feminino , Hidrocarbonetos/análise , Masculino , Espectrometria de Massas , Mariposas/metabolismo , Análise de Componente Principal , Caracteres Sexuais , Fatores de Tempo
16.
Bioresour Technol ; 297: 122411, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31767431

RESUMO

Sulfonated activated carbon-based catalysts were prepared by microwaved-assisted carbonization of phosphoric acid activated corncob followed by sulfonation using concentrated sulfuric acid. Sulfonation at different temperatures and times resulted in varied SO3H group density of the SAC catalysts. Sulfonation temperature showed a significant effect on the introduction of SO3H on the AC precursor while time had minor role. The SAC catalysts were characterized by means of N2 sorption analysis (specific surface area, pore-volume, average pore width), FTIR spectroscopy, SEM imaging, and sulfur analysis. The impact of catalysts SO3H density on the product distribution and bio-oil composition from the catalytic co-pyrolysis of Douglas fir and LDPE was evaluated. The highest bio-jet fuels (aromatics and C9-16 alkanes) obtained was 97.51% using the SAC catalyst sulfonated at 100 °C for 5 h. Results showed that SAC has great potential as catalyst in the co-pyrolysis of biomass and plastics for the production of jet-fuel range hydrocarbons.


Assuntos
Carvão Vegetal , Plásticos , Biocombustíveis , Biomassa , Catálise , Temperatura Alta , Hidrocarbonetos
17.
Artigo em Inglês | MEDLINE | ID: mdl-31639315

RESUMO

The contamination of foods with mineral oil hydrocarbons (MOH) is a serious concern, requiring in most cases tedious mitigation measures that span across the whole food supply chain. A major issue today is the significant variability of the results generated by laboratories. This study was therefore designed to achieve a deeper insight into the analytical procedures used by commercial laboratories, identifying possible gaps and suggesting improvements that will enhance the reliability of the MOH data, an important prerequisite for risk assessment. In total six different food matrices, i.e. infant formula (IF), cocoa butter, cocoa powder, biscuits, fruit-based baby food containing biscuit and roast and ground coffee were subjected to comparative inter-laboratory studies, as well as one vegetable oil analysed within the frame of a professionally conducted proficiency test. The results indicate that on some matrices with possibly low amounts of MOH contamination, the current methodologies cannot reliably conclude whether or not a food sample is indeed contaminated with mineral oils (<10 mg/kg food). Urgently needed are: (i) an aligned and fully validated sample preparation strategy tested on a range of different food matrices; (ii) a confirmation of positive flame ionisation detection (FID) results by confirmatory methods such as mass spectrometry - in line with the CEN Standard and the Joint Research Centre (JRC) Guidance Document, (iii) a more detailed root-cause analysis in the reports of laboratories through the use of mineral oil markers, and (iv) a fully validated official method for the concerned foods with a limit of application <10 mg/kg food.


Assuntos
Análise de Alimentos , Contaminação de Alimentos/análise , Hidrocarbonetos/análise , Óleo Mineral/análise , Chocolate/análise , Café/química , Gorduras na Dieta/análise , Farinha/análise , Análise de Alimentos/normas , Frutas/química , Humanos , Lactente , Fórmulas Infantis/química , Reprodutibilidade dos Testes
19.
J Mass Spectrom ; 55(1): e4482, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31782217

RESUMO

Ricin, a plant-derived toxin extracted from the seeds of Ricinus communis (castor bean plant), is one of the most toxic proteins known. Ricin's high toxicity, widespread availability, and ease of its extraction make it a potential agent for bioterrorist attacks. Most ricin detection methods are based on immunoassays. These methods may suffer from low efficiency in matrices containing interfering substances, or from false positive results due to antibody cross reactivity, with highly homologous proteins. In this study, we have developed a simple, rapid, sensitive, and selective mass spectrometry assay, for the identification of ricin in complex environmental samples. This assay involves three main stages: (a) Ricin affinity capture by commercial lactamyl-agarose (LA) beads. (b) Tryptic digestion. (c) LC-MS/MS (MRM) analysis of tryptic fragments. The assay was validated using 60 diverse environmental samples such as soil, asphalt, and vegetation, taken from various geographic regions. The assay's selectivity was established in the presence of high concentrations of competing lectin interferences. Based on our findings, we have defined strict criteria for unambiguous identification of ricin. Our novel method, which combines affinity capture beads followed by MRM-based analysis, enabled the identification of 1 ppb ricin spiked into complex environmental matrices. This methodology has the potential to be extended for the identification of ricin in body fluids from individuals exposed (deliberately or accidentally) to the toxin, contaminated food or for the detection of the entire family of RIP-II toxins, by applying multiplex format.


Assuntos
Lactamas/química , Extratos Vegetais/química , Ricina/análise , Sefarose/química , Espectrometria de Massas em Tandem/métodos , Cromatografia Líquida de Alta Pressão , Geografia , Hidrocarbonetos/química , Microesferas , Ricinus/química , Sementes/química , Solo/química
20.
J Environ Manage ; 256: 109913, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31818738

RESUMO

Interfacing organic or inorganic nanoparticles with biological entities or molecules or systems with the aim of developing functionalized nano-scale materials or composites for remediation of persistent organic hydrocarbon pollutants (such as monocyclic and polycyclic aromatic hydrocarbons, MAH/PAH) has generated great interest and continues to grow almost unabated. However, the usefulness and potency of these materials or conjugates hinges over several key barriers, including structural assembly with fine-tuned control over nanoparticle/biomolecule ratio, spatial orientation and activity of biomolecules, the nano/bio-interface strategy and hierarchical architecture, water-dispersibility and long term colloidal stability in environmental media, and non-specific toxicity. The present review thus critically analyses, discusses and interprets recently reported attempts and approaches to functionalize nanoparticles with biomolecules. Since there is no comprehensive and critical reviews on the applications of nanotechnology in bioremediation of MAHs/PAHs, this overview essentially captures the current global scenario and vision on the use and future prospects of biofunctionalized nanomaterials with respect to their strategic interactions involved at the nano/bio-interface essential to understand and decipher the structural and functional relationships and their impact on persistent hydrocarbon remediation.


Assuntos
Nanoestruturas , Hidrocarbonetos Policíclicos Aromáticos , Biodegradação Ambiental , Hidrocarbonetos , Nanotecnologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA