Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 8.687
Filtrar
1.
Chemosphere ; 310: 136863, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36244419

RESUMO

The non-point source pollution of difenoconazole (DIF) has become a serious environmental issue, increasingly causes indelible damages to eco-environment and human health due to its toxicity, persistence, and biomagnification. An eco-friendly, cost-effective, and efficient control technology is imperative towards a cleaner and sustainable agricultural production. Herein, a dominant microflora of efficiently degrading DIF was successfully screened, and its microbial diversity was investigated. Two novel degrading strains were isolated and identified as Phyllobacterium sp. (T-1) and Aeromonas sp. (T-2). The results of growth factor optimization indicated that the degradation rates of DIF (C0 = 20 mg/L) by strain T-1 and T-2 were up to 96.32% and 97.86% within 14 d, respectively, under the optimal conditions. Moreover, there no obvious synergy between strain T-1 and strain T-2. From catalytic kinetics of enzymes, the intracellular enzyme of strain T-1 dominated the degradation of DIF (C0 = 20 mg/L) entirely with the degradation rate of 82.4% (48 h), the extracellular enzyme showed little catalytic activity. However, the degrade rates of DIF (C0 = 20 mg/L) by both intracellular and extracellular enzymes of strain T-2 were 77.99% and 26.73% within 48 h, respectively. Moreover, these enzymes remained an undiminished catalytic activity within 48 h. DIF was degraded by strain T-1 to three main transformation products (DIF-TPs 406, DIF-TPs 216, and DIF-TPs 198) undergoing hydroxyl substitution, hydrolysis, cleavage of ether bond between benzene rings, and rearrangement, while two additional products (DIF-TPs 281 and DIF-TPs 237) were generated with the biodegradation of strain T-2, excepting for DIF-TPs 406 and DIF-TPs 216, involving hydrolysis, hydroxylation, and ether bond cleavage between benzene rings. Moreover, QSAR simulation showed that the by-products were almost much lower toxicity or even non-toxic to three typical aquatic organisms (fish, daphnia, and green algae) than DIF. This study not only provides an in depth understanding of DIF bioelimination, but also be instrumental in cleaner management of DIF-contaminated soil. This study can promote the sustainable development of agriculture.


Assuntos
Benzeno , Microbiota , Biodegradação Ambiental , Éteres
2.
Sci Total Environ ; 856(Pt 1): 159025, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36167136

RESUMO

Investigators are debating on the positive and negative priming effects of biochar on native soil organic carbon (SOC), which is largely attributed to the technical barrier of identifying biochar contribution to the apparently measured SOC or mineralized CO2. We combined benzene polycarboxylic acids (BPCAs) molecular biomarkers and soil particle density fractionation to identify biochar contributions to the carbon content in three representative allitic soils in Yunnan. The soil-biochar mixture was incubated for one-month to avoid significant biodegradation of biochar. The results showed that BPCAs were mainly distributed in free light fractions (fLF) up to 87 % of the total BPCAs contents after one month incubation. Recognition of BPCAs in occluded light fractions (oLF) and heavy fractions (HF) suggested a significant interaction between biochar and soil mineral particles. In addition, the percentage of B6CA is comparable or even higher in HF than in fLF or oLF. Thus, biochar-mineral interactions may be an additional stabilization mechanism besides the condensed aromatic structures in biochar. The apparently measured carbon contents increased after biochar application, and both positive and negative priming effects to native SOC were observed after deducting biochar contents based an accurate calculation from BPCAs. The most native SOC depletion (positive priming effects) was noted for the soil with the most favored biochar embedding in soil mineral compositions. This study emphasized that combining BPCAs molecular biomarkers and soil particle density fractionation could accurately quantify different carbon pools, and thus facilitate a comprehensive understanding on the stabilization and turnover of biochar in soils.


Assuntos
Benzeno , Solo , Solo/química , Benzeno/análise , Carbono/análise , China , Carvão Vegetal/química , Minerais , Ácidos Carboxílicos , Biomarcadores
3.
Sci Total Environ ; 856(Pt 2): 159066, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36174682

RESUMO

In this study, a cutting-edge mass spectrometry (MS) technique, Orbitrap fusion MS with ultrahigh resolution, was used to analyze the molecular composition, chemical properties, formation mechanism, and environmental impact of refractory dissolved organic matter (rDOM) in leachate. The results showed that the bioavailable DOM (bDOM) and rDOM constituents varied substantially during the biological treatment of landfill leachate. Compared with bDOM, the rDOM in leachate had a higher degree of unsaturation, aromaticity, and oxidation, and a larger molecular weight, and contained more organic matter with benzene ring and biphenyl structures. Using high-throughput 16S rRNA sequencing, metagenomics, the Kendrick mass defect (KMD), and a mass difference network (MDiN), it was found that rDOM in leachate is generated through carboxylation (+COO), dehydro-oligomerization (-H2), and chain scission (-CH2) pathways due to the activity of microbes such as Patescibacteria, Chloroflexi, and Proteobacteria. Compared with Suwannee River fulvic acid (SRFA), the rDOM in leachate contained more organics with nitrogen, sulfur, benzene rings, and biphenyls. If the rDOM in leachate enters the environment it will affect the composition of the original organic matter, and its biogeochemical transformation and environmental fate will then need to be monitored and may require special attention.


Assuntos
Poluentes Químicos da Água , Poluentes Químicos da Água/análise , Matéria Orgânica Dissolvida , RNA Ribossômico 16S , Benzeno/análise , Reatores Biológicos
4.
Sci Total Environ ; 857(Pt 3): 159654, 2023 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-36280056

RESUMO

An ever-growing burden of scientific evidence links air pollution to different aspects of human health even at very low concentrations; the impact increases for those living in urban environments, especially the youngest and the elderly. This study investigated the exposure to air pollution of urban school children of Milan, Italy, by personal and biological monitoring, in the frame of the MAPS-MI project. A total of 128 primary school children (7-11 years) were involved in a two-season monitoring campaign during spring 2018 and winter 2019. Personal exposure to airborne VOCs and eBC, and biological monitoring of urinary benzene (BEN-U) and methyl-tert-butyl ether (MTBE-U) were performed. Time-activity patterns, environmental tobacco smoke (ETS), spatial, and meteorological information were evaluated as determinants in mixed effects regression analysis. Children personal exposure was mostly quantifiable with median (5th-95th percentile) levels 1.9 (0.8-7.5) µg/m3 for eBC, and 1.1 (<0.6-3.4) and 0.8 (0.3-1.8) µg/m3 for benzene and MTBE, respectively; with values 2-3-fold higher in winter than in spring. In urine, median (5th-95th) BEN-U and MTBE-U levels were 44.9 (25.7-98.6) and 11.5 (5.0-35.5) ng/L, respectively. Mixed effect regression models explained from 72 to 93 % of the total variability for air pollutants, and from 58 to 61 % for biomarkers. Major contributors of personal exposure were season, wind speed, mobility- or traffic-related variables; biomarkers were mostly predicted by airborne exposure and ETS. Our results suggest that traffic-mitigation actions, together with parents' educational interventions on ETS and commuting mode, should be undertaken to lower children exposure to air pollution.


Assuntos
Poluentes Atmosféricos , Emissões de Veículos , Criança , Humanos , Idoso , Emissões de Veículos/análise , Benzeno/análise , Monitoramento Biológico , Monitoramento Ambiental/métodos , Poluentes Atmosféricos/análise , Biomarcadores/análise , Exposição Ambiental/análise
5.
Sci Total Environ ; 856(Pt 2): 159187, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36202363

RESUMO

The continuous accumulation of chlorinated organic pollutants in soil poses a potential threat to ecosystems and human health alike. Alkali-catalyzed hydrothermal oxidation (HTO) can successfully remove chlorinated organic pollutants from water, but it is rarely applied to soil remediation. In this work, we assessed this technique to degrade and detoxify triclosan (TCS) in soil and we determined the underlying mechanisms. The results showed a dechlorination efficiency of TCS (100 mg per kg soil) of 49.03 % after 120 min reaction (H2O2/soil ratio 25 mL·g-1, reaction temperature 180 °C in presence of 1 g·L-1 NaOH). It was found that soil organic constituents (humic acid, HA) and inorganic minerals (SiO2, Al2O3, and CaCO3) suppressed the dechlorination degradation of TCS, with HA having the strongest inhibitory effect. During alkali-catalyzed HTO, the TCS molecules were effectively destroyed and humic acid-like or fulvic acid-like organics with oxygen functional groups were generated. Fluorescence spectroscopy analysis showed that hydroxyl radicals (OH) were the dominant reactive species of TCS degradation in soil. On the basis of the Fukui function and the degradation intermediates, two degradation pathways were proposed. One started with cleavage of the ether bond between the benzene rings of TCS, followed by dechlorination and the opening of benzene via oxidation. The other pathway started with direct hydroxylation of the benzene rings of TCS, after which they were opened and dechlorinated through oxidation. Analysis of the soil structure before and after treatment revealed that the soil surface changed from rough to smooth without affecting soil surface elements. Finally, biotoxicity tests proved that alkali-catalyzed HTO effectively reduced the toxicity of TCS-contaminated soil. This study suggests that alkali-catalyzed hydrothermal oxidation provides an environmentally friendly approach for the treatment of soil contaminated with chlorinated organics such as TCS.


Assuntos
Poluentes Ambientais , Triclosan , Poluentes Químicos da Água , Humanos , Triclosan/metabolismo , Substâncias Húmicas , Solo , Peróxido de Hidrogênio , Álcalis , Benzeno , Ecossistema , Dióxido de Silício , Catálise , Poluentes Químicos da Água/análise
6.
J Environ Manage ; 325(Pt A): 116435, 2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36270122

RESUMO

Benzene (B), toluene (T), ethylbenzene (E), and xylenes (X) are petrochemicals vital in various industrial and commercial processing but identified as priority pollutants due to their high toxicity. The objective of this study was to investigate the toxicological nature of BTEX mixtures under controlled laboratory aquatic conditions using sulfur-oxidizing bacteria (SOB). Results from individual BTEX tests demonstrated that the order of toxicity among BTEX was X ≥ E > T > B. Comparisons of dose-effect curves for BTEX suggest that the biochemical mode of action of B in SOB was different from those of T, E, and X. Toxicological interactions of BTEX in mixtures were studied using concentration addition (CA), independent action (IA), and combination index (CI)-isobologram models. The CI model approximated the actual toxicity of BTEX mixtures better than the CA and IA models. In most cases, BTEX induced synergistic interactions in mixtures. However, in some B-containing mixtures, antagonism was observed at low effective levels. The effective level (fa)-CI plots and polygonograms illustrate that synergistic interactions of BTEX became stronger with an increase in effective levels. In addition, ternary and quaternary mixtures were found to provoke stronger synergism than binary mixtures. The present study suggests that the CI-isobologram model is a suitable means to evaluate diverse toxicological interactions of contaminants in mixtures.


Assuntos
Derivados de Benzeno , Xilenos , Biodegradação Ambiental , Xilenos/toxicidade , Derivados de Benzeno/toxicidade , Tolueno/toxicidade , Benzeno/toxicidade , Enxofre , Bactérias , Oxirredução
7.
J Colloid Interface Sci ; 630(Pt B): 301-316, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36327733

RESUMO

Catalytic oxidation is considered as the most effective and economical method to remove low concentration volatile organic compounds (VOCs). Activation of oxygen to form active oxygen species on metal oxides catalyst plays a key role in the process. Three copper-manganese oxide catalysts with cubic Cu1.5Mn1.5O4 phases were prepared by microwave heating (CM-MW), sol-gel (CM-SG) and co-precipitation (CM-CP) methods, and applied for the elimination of toluene and benzene as representative aromatic VOCs. These catalysts exhibit different catalytic oxidation performance due to their different physicochemical properties. Various characterizations were used to clarify the role of different oxygen species in the oxidation of VOCs, and the reaction pathway. In situ DRIFTS were carried out to explore the function of surface adsorbed oxygen, oxygen vacancy, and surface lattice oxygen in the catalytic oxidation of VOCs over three catalysts. Various types of intermediate species and detailed reaction pathways are also explored by combining in situ DRIFTS and mass spectrometry. Among these catalysts, CM-MW with nanosheet morphology shows the best catalytic oxidation performance of toluene and/or benzene with/without H2O due to the most abundant active oxygen species, and the highest oxygen vacancy concentration which is beneficial to activate oxygen. Meanwhile, toluene and benzene do not interfere with each other during the mixture oxidation. This study can provide new inspiration for rational design of metal oxide catalysts to remove VOCs.


Assuntos
Tolueno , Compostos Orgânicos Voláteis , Tolueno/análise , Tolueno/química , Benzeno/química , Oxigênio/química , Espécies Reativas de Oxigênio , Óxidos/química , Catálise , Compostos Orgânicos Voláteis/química
8.
J Environ Manage ; 325(Pt B): 116659, 2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36335702

RESUMO

Landfill sites are sources of gaseous volatile compounds. The dumping area (LDA) and leachate storage pool (LSP) of two typical rural domestic waste landfill sites in north China (NLF) and southwest China (SLF) were investigated. We found that 45, 46, 61 and 68 volatile organic compounds (VOC) were present in the air of NLF-LDA, NLF-LSP, SLF-LDA, and SLF-LSP, respectively. And there were 27, 29, 35 and 37 kinds of odorous compounds being detected. Oxygenated compounds (>48.88%), chlorinated compounds (>6.85%), and aromatics (>5.46%), such as organic acid, 1-chlorobutane, and benzene, were the most abundant compounds in both landfills. The SLF-LDA had the highest olfactory effect, with a corresponding total odor activity value of 29,635.39. The ozone-formation potential analysis showed that VOCs emitted from SLF landfills had significantly higher potential for ozone formation than those from NLF landfills, with ozone generation potentials of 166.02, 225.86, 2511.82, and 1615.99 mg/m3 for the NLF-LDA, NLF-LSP, SLF-LDA, and SLF-LSP, respectively. Higher chronic toxicity and cancer risk of VOCs were found in the SLF according to method of Risk Assessment Information System. Based on the sensitivity analysis by the Monte Carlo method, concentrations of benzene, propylene oxide, propylene, trichloroethylene, and N-nitrosodiethylamine, along with exposure duration, daily exposure time, and annual exposure frequency, significantly impacted the risk levels. We provide a scientific basis, which reflects the need for controlling and reducing gaseous pollutants from landfills, particularly rural residential landfills, which may improve rural sanitation.


Assuntos
Poluentes Atmosféricos , Ozônio , Compostos Orgânicos Voláteis , Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Benzeno , Instalações de Eliminação de Resíduos , Ozônio/análise , Compostos Orgânicos Voláteis/análise , China
9.
J Hazard Mater ; 441: 129881, 2023 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-36063710

RESUMO

Microplastics (MPs) are frequently detected in urban waters, which would pose a threat to human health through the food chain. Thus, efficient approaches to the elimination of MPs are urgently required. Pyrolysis is a powerful technique for the potential treatment of MPs. The online thermogravimetry-Fourier transform infrared reflection-Mass spectrometry (TG-FTIR-MS) is applied for tracking the pyrolysis process of representative polyethylene (PE) and polyvinyl chloride (PVC) MPs in urban waters, together with or without the FeAlOx catalyst. TG could quantitatively determine the decomposition behavior and kinetics of MPs while FTIR and MS spectra would be capable of characterizing the pyrolysis products. The results revealed that FeAlOx is an excellent carbon support, and the deposited carbon can be gasified to CO at higher pyrolysis temperatures. Moreover, more aromatic compounds were generated from the pyrolysis of PE MPs with the catalyzation of FeAlOx. Large quantities of benzene were also produced in the PVC MPs pyrolysis with or without FeAlOx. Also, FeAlOx largely decreased the concentrations of chlorine-containing compounds in the liquid products of PVC MPs pyrolysis. This study provides a efficient technique for the online observation of the MPs' catalytic pyrolysis process, which would guide future upcycling of MPs into value-added products.


Assuntos
Microplásticos , Cloreto de Polivinila , Benzeno , Carbono , Cloro , Humanos , Plásticos , Polietileno/química , Pirólise , Espectroscopia de Infravermelho com Transformada de Fourier
10.
J Environ Sci (China) ; 124: 644-654, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36182170

RESUMO

A solid phase extraction procedure (SPE) is described for the quantitative analysis of polycyclic aromatic hydrocarbons (PAHs) in atmospheric particulate matter (PM), as ubiquitous environmental pollutants routinely measured in air quality monitoring. A SPE cartridge was used based on a molecular imprinted polymer (MIP-SPE) properly tailored for selective retention of PAHs with 4 and more benzene fused rings. The performance of the clean-up procedure was evaluated with the specific concern of selective purification towards saturated hydrocarbons, which are the PM components mostly interfering GC analysis of target PAHs. Under optimized operative conditions, the MIP-SPE provided analyte recovery close to 95% for heavier PAHs, from benzo(α)pyrene to benzo(ghi)perylene, and close to 90% for four benzene rings PAHs, with good reproducibility (RSDs: 2.5%-5.9%). Otherwise, C17-C32n-alkanes were nearly completely removed. The proposed method was critically compared with Solid Phase Micro Extraction (SPME) using a polyacrylate fiber. Both methods were successfully applied to the analysis of ambient PM2.5 samples collected at an urban polluted site. Between the two procedures, the MIP-SPE provided the highest recovery (R% ≥ 93%) for PAHs with 5 and more benzene rings, but lower for lighter PAHs. In contrast, SPME showed a mean acceptable R% value (∼ 80%) for all the investigated PAHs, except for the heaviest PAHs in the most polluted samples (R%: 110%-138%), suggesting an incomplete purification from the interfering n-hydrocarbons.


Assuntos
Poluentes Ambientais , Hidrocarbonetos Policíclicos Aromáticos , Alcanos/análise , Benzeno , Benzo(a)pireno/análise , Poeira/análise , Poluentes Ambientais/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Polímeros Molecularmente Impressos , Material Particulado/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Reprodutibilidade dos Testes
11.
Environ Monit Assess ; 195(1): 60, 2022 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-36326946

RESUMO

The present study intends to use machine learning (ML) and deep learning (DL) models to forecast PM2.5 concentration at a location in Delhi. For this purpose, multi-layer feed-forward neural network (MLFFNN), support vector machine (SVM), random forest (RF) and long short-term memory networks (LSTM) have been applied. The air pollutants, e.g., CO, Ozone, PM10, NO, NO2, NOx, NH3, SO2, benzene, toluene, as well as meteorological parameters (temperature, wind speed, wind direction, rainfall, evaporation, humidity, pressure, etc.), have been used as inputs in the present study. Moreover, this is one of the first papers that employ aerodynamic roughness coefficient as an input parameter for the prediction of PM2.5 concentration. The result of the study shows that the LSTM model with index of agreement (IA) 0.986, root mean square error (RMSE) 21.510, Nash-Sutcliffe efficiency index (NSE) 0.945, (coefficient of determination)R2 0.945, and (correlation coefficient)R 0.972 is the best performing technique for the prediction of PM2.5 followed by MLFFNN, SVM, and RF models. The sensitivity analysis for the LSTM model reported that PM10, wind speed, NH3, and benzene are the key influencing parameters for the estimation of PM2.5. The findings in this work suggest that the LSTM could advance in PM2.5 forecasting and thus would be useful for developing fine-scale, state-of-the-art air pollution forecasting models.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Aprendizado Profundo , Benzeno/análise , Monitoramento Ambiental/métodos , Poluentes Atmosféricos/análise , Poluição do Ar/análise , Aprendizado de Máquina , Material Particulado/análise
12.
J Toxicol Sci ; 47(11): 457-466, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36328536

RESUMO

Although both o-toluidine and o-anisidine are known as aromatic amines with bladder carcinogenicity, the specific metabolites involved in carcinogenesis are still unclear. Here, we examined the toxicological effects of head-to-tail dimers of o-toluidine and o-anisidine, 2-methyl-N4-(2-methylphenyl) benzene-1,4-diamine (MMBD) and 2-methoxy-N4-(2-methoxyphenyl) benzene-1,4-diamine (MxMxBD), respectively, in rats. Six-week-old male F344 rats were orally administered MMBD, MxMxBD, o-toluidine, and o-anisidine at a dose of 100 mg/kg/day for 28 days. Rats administered 400 mg/kg o-toluidine and 600 mg/kg/day o-anisidine were set as high-dose groups for comparison. Histopathology and immunohistochemistry for γ-H2AX, a DNA damage biomarker, and bladder stem cell markers, including aldehyde dehydrogenase 1A1 (ALDH1A1), were performed. MMBD and MxMxBD caused different toxicities than their monomers, inducing hepatotoxicity such as vacuolar degeneration but not splenic lesions due to methemoglobinemia. Bladder lesions, including urothelial hyperplasia, were observed in the high-dose o-toluidine and o-anisidine groups, whereas no obvious changes were induced in the low-dose groups or their dimers. Although γ-H2AX formation was significantly increased by o-toluidine and o-anisidine treatment, γ-H2AX formation did not differ among the MMBD, MxMxBD, and control groups. Notably, immunohistochemistry revealed marked increases in ALDH1A1 expression in the bladder urothelium of the MMBD and MxMxBD groups and in the o-toluidine and o-anisidine groups, suggesting that the two dimers may contribute to the bladder carcinogenic effects of o-toluidine and o-anisidine to some extent. The degrees of bladder lesions and γ-H2AX formation did not correlate with the amount of unchanged o-toluidine and o-anisidine in urine, indicating the presence of other metabolites responsible for these findings.


Assuntos
Benzeno , Diaminas , Ratos , Masculino , Animais , Ratos Endogâmicos F344 , Administração Oral
13.
Sci Rep ; 12(1): 19651, 2022 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-36385330

RESUMO

Fuel components such as benzene, toluene, and methyl tertiary-butyl ether (MTBE) are frequently detected pollutants in groundwater resources. Ex-situ remediation technologies by activated carbon have been used for treatment for many years. However, due to high cost of these technology, more attention has been given to the in-situ remediation methods of contaminated groundwaters using liquid carbon adsorbents. Literature search showed limited studies on using adsorbents in liquid form for the removal of such contaminants. Therefore, this lab-scale study investigates the capacity of using raw biochar-based liquid activated carbon and iron-modified biochar-based liquid activated carbon to remove these pollutants. The adsorption efficiency of the synthesized liquid activated carbon and iron-modified liquid activated carbon mixed with sand, limestone, and 1:1 mixture of sand/limestone, was tested using batch suspension experiments. Adsorption by granular activated carbon was also investigated for comparison with liquid activated carbon. Results of the study revealed that mixing of liquid activated carbon or LAC-Fe on subsurface materials had not improved the removal efficiency of MTBE. At the same time, it showed a slight improvement in the adsorption efficiency of benzene and toluene. In all cases, the removal by GAC was higher with around 80% and 90% for MTBE and BT, respectively. Results also showed that benzene and toluene were better removed by liquid activated carbon and iron-modified liquid activated carbon (∼ 40%) than MTBE (∼ 20%). It is also found that water chemistry (i.e., salinity and pH) had insignificant effects on the removal efficiency of pollutants under the study conditions. It can be concluded that more research is needed to improve the capacity of biochar-based liquid-activated carbon in removing MTBE, benzene and toluene compounds that will lead to improve the utilization of liquid activated carbon for the in-situ remediation of contaminated groundwaters.


Assuntos
Carvão Vegetal , Poluentes Ambientais , Benzeno , Tolueno , Areia , Ferro/química , Carbonato de Cálcio
14.
J Contam Hydrol ; 251: 104099, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36369109

RESUMO

Increased oil production in Canada has resulted in proposals to extend or develop new oil pipelines. Many of these proposals have been met by concerns from the public over potential environmental impacts related to construction and the potential for oil spills to negatively affect groundwater quality. Crude oil sourced from the Alberta oil sands represents a significant proportion of this increase in production. This crude oil is produced as bitumen, which is subsequently diluted with light hydrocarbons to lower viscosity to allow for pipeline transport producing diluted bitumen. In this study, we pumped water through tanks filled with sand to simulate groundwater flow. Tanks were injected with either conventional crude or diluted bitumen to simulate a crude oil spill from a pipeline rupture occurring below the water table representing a pipeline river crossing scenario. Water samples were collected from the downstream end of the tanks throughout the experiment period (∼two months). Compared to water quality guidelines, effluent waters from both conventional crude and diluted bitumen tanks contained elevated concentrations of dissolved organic compounds, particularly benzene, ethylbenzene, toluene and xylenes (BTEX). The effluent from each tank had similar concentrations of benzene, whereas discharge water from conventional crude tanks contained higher concentrations of ethylbenzene, toluene and xylenes. In both tanks, and as expected, the BTEX concentrations appeared to be proportional to those determined in their injected crude oils. The measured dissolved concentrations of benzene, ethylbenzene and toluene are lower than predicted which is attributed largely due to dilution along the flow path. In addition to organic constituents, effluent sampled from the diluted bitumen tank contained some metals (Co, Cr, Fe and V) which measured constituents of the oil.


Assuntos
Petróleo , Poluentes Químicos da Água , Xilenos , Benzeno , Campos de Petróleo e Gás , Poluentes Químicos da Água/análise , Hidrocarbonetos , Tolueno , Alberta
15.
Molecules ; 27(21)2022 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-36364337

RESUMO

Monoacylglycerol lipase (MAGL) can regulate the endocannabinoid system and thus becomes a target of antidepressant drugs. In this paper, molecular docking and molecular dynamics simulations, combined with binding free energy calculation, were employed to investigate the inhibitory mechanism and binding modes of four aryl formyl piperidine derivative inhibitors with different 1-substituents to MAGL. The results showed that in the four systems, the main four regions where the enzyme bound to the inhibitor included around the head aromatic ring, the head carbonyl oxygen, the tail amide bond, and the tail benzene ring. The significant conformational changes in the more flexible lid domain of the enzyme were caused by 1-substituted group differences of inhibitors and resulted in different degrees of flipping in the tail of the inhibitor. The flipping led to a different direction of the tail amide bond and made a greater variation in its interaction with some of the charged residues in the enzyme, which further contributed to a different swing of the tail benzene ring. If the swing is large enough, it can weaken the binding strength of the head carbonyl oxygen to its nearby residues, and even the whole inhibitor with the enzyme so that the inhibition decreases.


Assuntos
Simulação de Dinâmica Molecular , Monoacilglicerol Lipases , Simulação de Acoplamento Molecular , Benzeno , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/química , Piperidinas/farmacologia , Piperidinas/química , Amidas , Oxigênio
16.
Sci Rep ; 12(1): 18609, 2022 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-36329092

RESUMO

Benzene, toluene and xylene (BTX) are volatile organic compounds released into the environment, that require urgent removal to avoid adverse health effects. In this work, the modelling and optimization of the preparation factors for magnetite coated oleic acid (MNP-OA) composite from microwave synthesis using response surface methodology were conducted to maximize BTX removal, and iron content. The influence of five crucial preparation variables: the Fe3+/Fe2+ solution volumes, microwave power, volume of ammonia water (VAW), reaction time and volume of oleic acid (VOA) on the iron content (% Fe), and BTX adsorption capacity were investigated. The analysis of variance results revealed that VOA and VAW were the most influential factors for high % Fe content, and improved BTX removal. The % Fe, and BTX adsorption capacity for MNP-OA composite at optimized experimental conditions were estimated to be 85.57%, 90.02 mg/g (benzene), 90.07 mg/g (toluene), and 96.31 mg/g (xylene).


Assuntos
Tolueno , Xilenos , Benzeno , Óxido Ferroso-Férrico , Ácido Oleico , Micro-Ondas , Ferro
17.
Se Pu ; 40(11): 1031-1038, 2022 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-36351812

RESUMO

Pomelo peel, as a by-product of pomelo consumption, is rich in various fiber and functional compounds. The utilization of the valuable components found in pomelo peel may mitigate environmental concerns. In this study, pomelo peel rich in lignin and oxygen-containing functional groups was used to prepare pomelo peel biochar (PPB) via temperature-programmed pyrolysis at different temperatures (800 ℃ and 1000 ℃). Their structures were investigated by N2 adsorption-desorption isotherms and BJH pore size distribution. The results showed that PPB1000 (pomelo peel biochar prepared at 1000 ℃) had a higher specific surface area (749.9 m2/g), larger pore volume (0.42 cm3/g), more concentrated pore size distribution (2-3 nm), and better adsorption performance than commercial activated carbon. PPB1000 exhibited excellent capability to capture benzenes (BTEX, including benzene (B), toluene (T), ethylbenzene (E), and xylene (X)) through hydrogen bonds, π-π, and electrostatic interactions. Additionally, their honeycomb porous structure could provide additional adsorption sites and material transport paths. PPB1000 was coated on iron wire using the sol-gel method to prepare chemically and mechanically stable solid phase microextraction (SPME) fibers. By combining PPB1000-based SPME analysis with gas chromatography-flame ionization detection (GC-FID), an effective method was developed for the extraction and determination of BTEX. The optimized method had low LODs (0.004-0.032 µg/L), wide linear range (1-100 µg/L), and good linear relationship (determination coefficients, r2≥0.9919). The RSDs of the intra-batch (n=6) and inter-batch (n=5) precisions were 1.04%-6.56% and 1.03%-12.42%, respectively. The method validation results showed that PPB1000 had good stability. Compared with the commercial reagent polydimethylsiloxane (7 µm), PPB1000 had a higher extraction efficiency. When applied to the analysis of BTEX in natural water samples, trace levels of ethylbenzene (4.80 µg/L), o-xylene (3. 00 µg/L), and m-xylene and p-xylene (2.46 µg/L) were detected. Recovery tests were performed to validate the reliability of the method, and recoveries were between 75.7% and 117.6%. This effective pretreatment process combined with GC-FID could realize the rapid detection of BTEX and is promising for the analysis of BTEX in complex matrixes in the future.


Assuntos
Benzeno , Microextração em Fase Sólida , Microextração em Fase Sólida/métodos , Benzeno/análise , Carvão Vegetal , Rios/química , Reprodutibilidade dos Testes , Água/análise
18.
Anal Methods ; 14(45): 4659-4668, 2022 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-36342027

RESUMO

Zeolitic imidazolate framework-8 modified magnetic halloysite nanotube (MHNTs@ZIF-8) composites were synthesized and evaluated for the first time as an efficient sorbent for the magnetic solid-phase extraction (mSPE) of carbamate pesticides (CPs) from water samples. MHNTs were prepared by coprecipitation, and MHNTs@ZIF-8 composites were assembled in situ at room temperature. After characterization, MHNTs@ZIF-8 was used to extract pirimicarb, propoxur, carbaryl, isoprocarb and fenobucarb via π-π stacking interaction and hydrophobic interaction between the imidazole skeleton of ZIF-8 and benzene rings or benzene-like rings in CPs, as well as the hydrogen bond formed between O in CPs and H in ZIF-8. The effects of the amount of sorbent, ionic strength, type and volume of desorption solvent and adsorption/desorption time were investigated. Under optimum conditions, good linearity was obtained for the analysis of CPs by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) with R2 ≥ 0.9992. The limits of quantification range from 3 to 40 ng L-1 in water. Relative standard deviations (RSDs) were <7%, n = 5, within a batch and <9% among batches. The spiked recoveries were between 81 and 104%. The proposed method has been successfully applied to the determination of CPs in various water samples.


Assuntos
Nanotubos , Praguicidas , Poluentes Químicos da Água , Zeolitas , Cromatografia Líquida de Alta Pressão/métodos , Zeolitas/química , Espectrometria de Massas em Tandem/métodos , Argila , Benzeno/análise , Poluentes Químicos da Água/análise , Extração em Fase Sólida/métodos , Praguicidas/análise , Carbamatos/análise , Ésteres , Nanotubos/análise , Água/análise , Fenômenos Magnéticos
19.
Molecules ; 27(22)2022 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-36432179

RESUMO

Halogen bonds play an important role in many fields, such as biological systems, drug design and crystal engineering. In this work, the structural characteristics of the halogen bond between heteronuclear halogen XD (ClF, BrCl, IBr, ICl, BrF and IF) and benzene were studied using density functional theory. The structures of the complexes between heteronuclear halogen and benzene have Cs symmetry. The interaction energies of the complexes between heteronuclear halogen XD (ClF, BrCl, IBr, ICl, BrF and IF) and benzene range from -27.80 to -37.18 kJ/mol, increasing with the increases in the polarity between the atoms of X and D, and are proportional to the angles of a between the Z axis and the covalent bond of heteronuclear halogen. The electron density (ρ) and corresponding Laplacian (∇2ρ) values indicate that the interaction of the heteronuclear halogen and benzene is a typical long-range weak interaction similar to a hydrogen bond. Independent gradient model analysis suggests that the van der Waals is the main interaction between the complexes of heteronuclear halogen and benzene. Symmetry-adapted perturbation theory analysis suggests that the electrostatic interaction is the dominant part in the complexes of C6H6⋯ClF, C6H6⋯ICl, C6H6⋯BrF and C6H6⋯IF, and the dispersion interaction is the main part in the complexes of C6H6⋯BrCl, C6H6⋯IBr.


Assuntos
Benzeno , Halogênios , Halogênios/química , Ligação de Hidrogênio , Eletricidade Estática , Modelos Moleculares
20.
Commun Biol ; 5(1): 1293, 2022 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-36434067

RESUMO

Strategies to prevent the recurrence of poliovirus (PV) after eradication may utilise non-infectious, recombinant virus-like particle (VLP) vaccines. Despite clear advantages over inactivated or attenuated virus vaccines, instability of VLPs can compromise their immunogenicity. Glutathione (GSH), an important cellular reducing agent, is a crucial co-factor for the morphogenesis of enteroviruses, including PV. We report cryo-EM structures of GSH bound to PV serotype 3 VLPs showing that it can enhance particle stability. GSH binds the positively charged pocket at the interprotomer interface shown recently to bind GSH in enterovirus F3 and putative antiviral benzene sulphonamide compounds in other enteroviruses. We show, using high-resolution cryo-EM, the binding of a benzene sulphonamide compound with a PV serotype 2 VLP, consistent with antiviral activity through over-stabilizing the interprotomer pocket, preventing the capsid rearrangements necessary for viral infection. Collectively, these results suggest GSH or an analogous tight-binding antiviral offers the potential for stabilizing VLP vaccines.


Assuntos
Enterovirus , Poliovirus , Vacinas de Partículas Semelhantes a Vírus , Poliovirus/metabolismo , Antivirais/farmacologia , Benzeno , Sítios de Ligação , Antígenos Virais , Glutationa/metabolismo , Sulfonamidas
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...