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1.
J Environ Manage ; 316: 115219, 2022 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-35537272

RESUMO

The influence of Cl- on the formation mechanism of active components is often neglected in the Fe2+/peroxydisulfate (PDS) system containing a large amount of ferryl ion reactive specie (Fe(Ⅳ)). In the current investigation, the effects of Cl- concentration on the removal of methyl phenyl sulfoxide (PMSO), the formation of methyl phenyl sulfone (PMSO2), the transformation of reactive species and oxidation products were investigated under different reaction conditions that included Fe2+ dosage, PDS dosage, and pH0. The results showed that Cl- complexing Fe2+ increased the formation path of sulfate radical (SO4·-) in the Fe2+/PDS system. Fe2+ dosage and pH0 value affected the content and morphology of Fe2+-Cl- complex, thus affecting the composition of reactive species. According to the experiment of free radical steady-state concentration, it was found that low concentration of Cl- reacted with SO4·- and increased the steady-state concentration of chlorine radicals (8.09 × 10-13 M [·Cl]ss at 1.41 mM Cl-), while at high concentration of Cl-, the contents of SO4·-, hydroxyl radical (·OH) and dichloride anion radicals (Cl2·-) increased and the contents of Fe(Ⅳ) and ·Cl decreased. ·Cl had strong reactivity with PMSO, and PMSO and its oxidation products were chlorinated under the combined action of ·Cl and Cl2·-. This work reveals the reaction mechanism and environmental application risks of Fe2+/PDS technology and lays the groundwork for subsequent industrial application of Fe2+/PDS system.

2.
Front Immunol ; 13: 816689, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35493492

RESUMO

The gastrointestinal microbiota plays a vital role in ensuring the maintenance of host health through interactions with the immune system. The Heterophil/Lymphocyte (H/L) ratio reflects poultry's robustness and immune system status. Chickens with low H/L ratio are superior to the chickens with high H/L ratio in survival, immune response, and resistance to Salmonella infection, but the underlying mechanisms remain unclear. This study aimed to identify microorganisms associated with resistance to Salmonella Enteritidis infection in chickens based on the H/L ratio. The 16S rRNA and metagenomic analysis were conducted to examine microbiome and functional capacity between the 2 groups, and Short Chain Fatty Acids (SCFAs) and histopathology were conducted to explore the potential difference between susceptible and resistant groups at 7 and 21 days post-infection (dpi). The microbiome exploration revealed that low H/L ratio chickens, compared to high H/L ratio chickens, displayed a significantly higher abundance of Proteobacteria (Escherichia coli) and Bacteroidetes (Bacteroides plebeius) at 7 and 21 dpi, respectively. Anaerostipes (r = 0.63) and Lachnoclostridium (r = 0.63) were identified as bacterial genus significantly correlated with H/L (P < 0.001). Interestingly, Bacteroides was significantly and positively correlated with bodyweight post-infection (r = 0.72), propionate (r = 0.78) and valerate (r = 0.82) contents, while Salmonella was significantly and negatively correlated with bodyweight post-infection (r = - 0.67), propionate (r = - 0.61) and valerate (r = - 0.65) contents (P < 0.001). Furthermore, the comparative analysis of the functional capacity of cecal microbiota of the chickens with high and low H/L ratio revealed that the chickens with low H/L ratio possess more enriched immune pathways, lower antibiotic resistance genes and virulence factors compared to the chickens with high H/L ratio. These results suggest that the chickens with low H/L ratio are more resistant to Salmonella Enteritidis, and it is possible that the commensal Proteobacteria and Bacteroidetes are involved in this resistance against Salmonella infection. These findings provide valuable resources for selecting and breeding disease-resistant chickens.


Assuntos
Galinhas , Microbiota , Animais , Bacteroidetes , Linfócitos , Microbiota/genética , Propionatos , Proteobactérias/genética , RNA Ribossômico 16S/genética , Salmonella enteritidis , Valeratos
3.
Anal Methods ; 14(16): 1594-1602, 2022 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-35377369

RESUMO

Peanut shells are an agricultural by-product rich in flavonoids, but their utilization is not high at present. This research developed a method for the rational utilization of flavonoids in peanut shells, which could enhance the comprehensive utilization of peanut resources. A green and efficient natural extraction technique based on a natural deep eutectic solvent (NADES) and alkaline destruction was exploited for the extraction of the flavonoids from peanut shells. NADES synthesized with DL-menthol (Me) and DL-lactic acid (LA) was selected as the solvent. KOH was used as a destructive agent that could destroy the structure of Me/LA, which could aid not only recovering the flavonoids, but also aid Me recovery and recycling. The NADES with the molar ratio of Me to LA of 1 : 4 showed a higher extraction capacity for flavonoids and better maintenance of antioxidant activity than water and ethanol. The maximum extraction efficiency was 23.33 mg rutin equivalents per g. In addition, the mass-transfer kinetics model of flavonoids extraction was established using Fick's second law, which well fitted the experimental results and proved that the temperature had a significant effect on the extraction efficiency. These results offered some insights for the research and exploitation of an environmentally friendly method to extract bio-active flavonoids for future applications in actual industrial manufacturing.


Assuntos
Arachis , Álcalis , Flavonoides/química , Cinética , Solventes/química
4.
J Environ Manage ; 313: 114973, 2022 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-35398638

RESUMO

Soil heavy metal contamination caused by mining activities is a global issue. These heavy metals can be enriched in plants and animals through the food chain, and eventually transferred to the human system and threatening public health. Biochar, as an environmentally friendly soil remediation agent, can effectively immobilize heavy metals in soil. However, most researchers concern more about the remediation effect and mechanism of biochar for industrial and agricultural contaminated soil, while related reviews focusing on mining soil remediation are limited. Furthermore, the remediation effect of soil in mining areas is affected by many factors, such as physicochemical properties of biochar, pyrolysis conditions, soil conditions, mining environment and application method, which can lead to great differences in the remediation effect of biochar in diverse mining areas. Therefore, it is necessary to systematically unravel the relevant knowledge of biochar remediation, which can also provide a guide for future studies on biochar remediation of contaminated soils in mining areas. The present paper first reviews the negative effects of mining activities on soil and the advantages of biochar relative to other remediation methods, followed by the mechanism and influencing factors of biochar on reducing heavy metal migration and bioavailability in mining soil were systematically summarized. Finally, the main research directions and development trends in the future are pointed out, and suggestions for future development are proposed.


Assuntos
Recuperação e Remediação Ambiental , Metais Pesados , Poluentes do Solo , Animais , Carvão Vegetal/química , Metais Pesados/análise , Solo/química , Poluentes do Solo/análise
5.
Small ; : e2107997, 2022 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-35445554

RESUMO

Direct electrochemical conversion of CO2 to CO product powered by renewable electricity is widely advocated as an emerging strategy for alleviating CO2 emissions while addressing global energy issues. However, the development of low-cost and efficient electrocatalysts with high Faradaic efficiency for CO production (FECO ) and high current density remains a grand challenge. Herein, a robust single nickel atomic site electrocatalyst, which features isolated and dense single atomic NiN3 sites anchored on highly defective hierarchically micro-mesoporous carbon (Ni-SAs/HMMNC-800), to enable enhanced charge transport and more exposed active sites for catalyzing electrochemical CO2 -to-CO conversion, is reported. The Ni-SAs/HMMNC-800 catalyst achieves excellent activity and selectivity with high FECO values of >90% throughout a wide potential range (the FECO reaches 99.5% at -0.7 V vs reversible hydrogen electrode) and a CO partial current density as high as 13.0 mA cm-2 at -0.7 V versus reversible hydrogen electrode, as well as a far outstanding durability during long-term continuous operation, indicating a superior CO2 electroreduction performance than that of other reference samples and most of previously reported carbon-based single atom electrocatalysts. Experimental and density functional theory calculations reveal that atomic NiN3 coordination sites coupled adjacent defects are favorable to significantly enhancing the formation of COOH* reaction intermediates while suppressing the competing hydrogen evolution reaction, thereby enhancing the electrocatalytic activity for CO2 -to-CO reduction. Notably, this work provides a valuable new prospect for designing and synthesizing efficient and cost-effective single atom CO2 electroreduction catalysts for practical applications.

6.
Sci Total Environ ; 832: 155004, 2022 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-35381235

RESUMO

Rice is an important food crop that is susceptible to arsenic (As) contamination under paddy soil conditions depending on As uptake characteristics of the rice genotypes. Here we unveiled the significance of eighteen (fine and coarse) rice genotypes against As accumulation/tolerance, morphological and physiological response, and antioxidant enzymes-enabled defense pathways. Arsenic significantly affected rice plant morphological and physiological attributes, with relatively more impacts on fine compared to coarse genotypes. Grain, shoot, and root As uptake were lower in fine genotypes (0.002, 0.020, and 0.032 mg pot-1 DW, respectively) than that of coarse (0.031, 0.60, and 1.2 mg pot-1 DW, respectively). Various biochemical (pigment contents, hydrogen peroxide, lipid peroxidation) and defense (antioxidant enzymes) plant parameters indicated that the fine genotypes, notably Kainat and Basmati-385, possessed the highest As tolerance. Arsenic-induced risk indices exhibited greater hazard quotient (up to 1.47) and carcinogenic risk (up to 0.0066) for coarse genotypes compared to the fine ones, with the greatest risk for KSK-282. This study elaborates the pivotal role of genotypic variation among rice plants in As accumulation, which is crucial for mitigating the associated human health risk. Further research is required on molecular aspects, e.g., genetic sequencing, to examine rice genotypes variation in defense mechanisms to As contamination.

7.
RSC Adv ; 12(5): 2693-2700, 2022 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-35425290

RESUMO

Using first-principles density-functional theory simulations, we explore the effects of hydrogenation and strain on the mechanical, electronic and transport properties of two-dimensional ZnSb monolayers. We find that the fully hydrogenated ZnSb monolayer exhibits large mechanical anisotropy between armchair and zigzag directions and the biaxial tensile strain reduces the anisotropy. In addition, we find that the hydrogenation can induce a metal-to-semiconductor transition with a direct band gap of 1.12 (1.92) eV using the PBE (HSE) functional. With biaxial strains, the band gaps decrease monotonically and remain direct for strains smaller than 5%. Moreover, large transport anisotropy is demonstrated by computing the effective masses of charge carriers along the asymmetric armchair and zigzag directions. We further reveal that strain can significantly tune the effective masses and a 3% strain can even switch the effective transport direction for holes. Our simulations suggest that the hydrogenated ZnSb monolayer is a promising candidate for electronic and opto-electronic applications with controllable modification via strain engineering.

8.
Chem Biol Interact ; 360: 109934, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35429547

RESUMO

Acrylonitrile is an organic chemical synthetic monomer that is widely used in food packaging and manufacturing. Animal studies have reported that acrylonitrile is carcinogenic and toxic, but the effects on the female reproductive function in mammals are unknown. In the present study, we report that acrylonitrile treatment affects ovarian homeostasis in mice, resulting in impaired follicular development. Follicles in acrylonitrile-exposed mice exhibited high levels of inflammation and apoptosis, and acrylonitrile treatment interfered with oocyte development. Transcriptomics analysis showed that acrylonitrile altered the expression of oocyte genes related to apoptosis, oxidative stress, endoplasmic reticulum stress, and autophagy. Further molecular tests revealed that acrylonitrile induced early apoptosis, DNA damage, elevated levels of reactive oxygen species, endoplasmic reticulum abnormalities, and lysosomal aggregation. We also observed disruption of mitochondrial structure and distribution and depolarization of membrane potential. Finally, acrylonitrile treatment in female mice decreased the number and weight of offspring. Altogether, these findings suggest that acrylonitrile impairs the stability of the ovarian internal environment, which in turn affects oocyte development and reduces the number of offspring.


Assuntos
Acrilonitrila , Acrilonitrila/metabolismo , Acrilonitrila/toxicidade , Animais , Apoptose , Feminino , Inflamação/metabolismo , Mamíferos , Camundongos , Mitocôndrias/metabolismo , Oócitos
9.
Chemosphere ; 301: 134590, 2022 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-35427661

RESUMO

A better understanding of different retention mechanisms of potentially toxic elements (PTEs) by biochars during the remediation of contaminated sites is critically needed. In this study, different spectroscopic techniques including synchrotron-based micro-X-ray fluorescence (µ-XRF), X-ray absorption fine structure (XAFS), and near-edge XAFS spectroscopy (NEXAFS), were used to investigate the spatial distributions and retention mechanisms of lead (Pb) and copper (Cu) on phytolith-rich coconut-fiber biochar (CFB), and ammonia, nitric acid and hydrogen peroxide modified CFB (MCFB) (i.e., ACFB, NCFB and HCFB). The µ-XRF analyses indicated that sorption sites on ACFB and NCFB were more efficient compared to those on CFB and HCFB to bind Pb/Cu. XAFS analyses revealed that the percentage of Pb species as Pb(C2H3O2)2 increased from 22.2% (Pb-loaded CFBs) to 47.4% and 41.9% on Pb-loaded NCFBs and HCFBs, while the percentage of Cu(OH)2 and Cu(C2H3O2)2 increased from 5.8% to 32.8% (Cu-loaded CFBs) to 41.5% and 43.4% (Cu-loaded NCFBs), and 27.1% and 35.1% (Cu-loaded HCFBs), respectively. Due to their similar atomic structures of Pb/Cu, Pb(C2H3O2)2/Pb-loaded montmorillonite and Cu(C2H3O2)2/Cu(OH)2 were identified as the predominant Pb/Cu species observed in Pb- and Cu-loaded MCFBs. The NEXAFS analyses of carbon confirmed that increasing amounts of carboxylic groups were formed on HCFB and NCFB by oxidizing carbon-containing functional groups, which could provide additional active binding sites for Pb/Cu retention. Results from the X-ray photoelectron spectroscopy analyses of nitrogen showed that azido-groups of ACFB played major roles in Pb/Cu retention, while amide-groups and pyridine-groups of NCFB primarily participated in Pb/Cu retention. Overall, density functional theory calculations suggested that silicate and the synergistic effect of hydroxyl and carboxylic-groups on MCFBs were highly efficient in Pb retention, while azido-groups and/or carboxylic-groups played major roles in Cu retention. These results provide novel insights into the PTE retention mechanisms of MCFBs.

10.
Adv Mater ; : e2200327, 2022 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-35322479

RESUMO

Novel non-collinear antiferromagnets with spontaneous time-reversal symmetry breaking, non-trivial band topology, and unconventional transport properties have received immense research interest over the past decade due to their rich physics and enormous promise in technological applications. One of the central focuses in this emerging field is exploring the relationship between the microscopic magnetic structure and exotic material properties. Here, nanoscale imaging of both spin-orbit-torque-induced deterministic magnetic switching and chiral spin rotation in non-collinear antiferromagnet Mn3 Sn films using nitrogen-vacancy (NV) centers are reported. Direct evidence of the off-resonance dipole-dipole coupling between the spin dynamics in Mn3 Sn and proximate NV centers is also demonstrated by NV relaxometry measurements. These results demonstrate the unique capabilities of NV centers in accessing the local information of the magnetic order and dynamics in these emergent quantum materials and suggest new opportunities for investigating the interplay between topology and magnetism in a broad range of topological magnets.

11.
Anal Chem ; 94(12): 5041-5047, 2022 03 29.
Artigo em Inglês | MEDLINE | ID: mdl-35294191

RESUMO

Atomic force microscopy (AFM) provides unprecedented insight into surface topography research with ultrahigh spatial resolution at the subnanometer level. However, a slow scanning rate has to be employed to ensure the image quality, which will largely increase the accumulated sample drift, thereby, resulting in the low fidelity of the AFM image. In this paper, we propose a fast imaging method which performs a complete fast Raster scanning and a slow µ-path subsampling together with a deep learning algorithm to rapidly produce an AFM image with high quality and small drift. A supervised convolutional neural network (CNN) model is trained with the slow µ-path subsampled data and its counterpart acquired with fast Raster scan. The fast speed acquired AFM image is then inputted to the well-trained CNN model to output the high quality one. We validate the reliability of this method using a silicon grids sample and further apply it to the fast imaging of a vanadium dioxide thin film. The results demonstrate that this method can largely improve the imaging speed up to 10.3 times with state-of-the-art imaging quality, and reduce the sample drift by 8.9 times in the multiframe AFM imaging of the same area. Furthermore, we prove that this method is also applicable to other scanning imaging techniques such as scanning electrochemical microscopy.


Assuntos
Algoritmos , Redes Neurais de Computação , Microscopia de Força Atômica/métodos , Reprodutibilidade dos Testes
12.
Nano Lett ; 22(7): 2755-2761, 2022 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-35315673

RESUMO

Oxide heterointerfaces with high carrier density can interact strongly with the lattice phonons, generating considerable plasmon-phonon coupling and thereby perturbing the fascinating optical and electronic properties, such as two-dimensional electron gas, ferromagnetism, and superconductivity. Here we use infrared-spectroscopic nanoimaging based on scattering-type scanning near-field optical microscopy (s-SNOM) to quantify the interaction of electron-phonon coupling and the spatial distribution of local charge carriers at the SrTiO3/TiO2 interface. We found an increased high-frequency dielectric constant (ε∞ = 7.1-9.0) and charge carrier density (n = 6.5 × 1019 to 1.5 × 1020 cm-3) near the heterointerface. Moreover, quantitative information between the charge carrier density and extension thickness across the heterointerface has been extracted by monochromatic near-field imaging. A direct evaluation of the relationship between the thickness and the interaction of charge carrier-phonon coupling of the heterointerface would provide valuable information for the development of oxide-based electronic devices.

13.
Environ Sci Technol ; 56(7): 3884-3893, 2022 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-35294173

RESUMO

Projection of future aerosols and understanding the driver of the aerosol changes are of great importance in improving the atmospheric environment and climate change mitigation. The latest Coupled Model Intercomparison Project Phase 6 (CMIP6) provides various climate projections but limited aerosol output. In this study, future near-surface aerosol concentrations from 2015 to 2100 are predicted based on a machine learning method. The machine learning model is trained with global atmospheric chemistry model results and projects aerosols with CMIP6 multi-model simulations, creatively estimating future aerosols with all important species considered. PM2.5 (particulate matter less than 2.5 µm in diameter) concentrations in 2095 (2091-2100 mean) are projected to decrease by 40% in East Asia, 20-35% in South Asia, and 15-25% in Europe and North America, compared to those in 2020 (2015-2024 mean), under low-emission scenarios (SSP1-2.6 and SSP2-4.5), which are mainly due to the presumed emission reductions. Driven by the climate change alone, PM2.5 concentrations would increase by 10-25% in northern China and western U.S. and decrease by 0-25% in southern China, South Asia, and Europe under the high forcing scenario (SSP5-8.5). A warmer climate exerts a stronger modulation on global aerosols. Climate-driven global future aerosol changes are found to be comparable to those contributed by changes in anthropogenic emissions over many regions of the world in high forcing scenarios, highlighting the importance of climate change in regulating future air quality.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Aerossóis/análise , Poluentes Atmosféricos/análise , Poluição do Ar/análise , Mudança Climática , Aprendizado de Máquina
15.
Mol Cell ; 82(7): 1313-1328.e8, 2022 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-35325613

RESUMO

AGO/miRNA-mediated gene silencing and ubiquitin-mediated protein quality control represent two fundamental mechanisms that control proper gene expression. Here, we unexpectedly discover that fly and human AGO proteins, which are key components in the miRNA pathway, undergo lipid-mediated phase separation and condense into RNP granules on the endoplasmic reticulum (ER) membrane to control protein production. Phase separation on the ER is mediated by electrostatic interactions between a conserved lipid-binding motif within the AGOs and the lipid PI(4,5)P2. The ER-localized AGO condensates recruit the E3 ubiquitin ligase Ltn1 to catalyze nascent-peptide ubiquitination and coordinate with the VCP-Ufd1-Npl4 complex to process unwanted protein products for proteasomal degradation. Collectively, our study provides insight into the understanding of post-transcription-translation coupling controlled by AGOs via lipid-mediated phase separation.


Assuntos
MicroRNAs , Ubiquitina-Proteína Ligases , Lipídeos , MicroRNAs/metabolismo , Peptídeos/metabolismo , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitinação
16.
Anal Methods ; 14(10): 1023-1030, 2022 03 10.
Artigo em Inglês | MEDLINE | ID: mdl-35188146

RESUMO

An aggregation-induced emission monomer-based fluorescent molecularly imprinted poly(ionic liquid) (AIE-FMIPIL) was synthesized for the first time with an AIE probe 4-(1,2,2-triphenylvinyl)phenyl acrylate (TPE), and an ionic liquid as dual functional monomers, and an ionic liquid as cross-linker. AIE-FMIPIL displayed a sphere-like shape and its average diameter was 410 nm. The absolute quantum yields of TPE and AIE-FMIPIL were 9.23% and 12.61%, respectively. The synergetic effect of TPE in the AIE-FMIPIL framework contributed to the higher quantum yield of AIE-FMIPIL. 4-Nitrophenol (4-NP) efficiently quenched AIE-FMIPIL with high fluorescence based on the Förster resonance energy transfer mechanism. The synthesized AIE-FMIPIL sensor was highly sensitive for 4-NP detection (linear range, 0.02-1.5 µM) in the optimal detection condition, with a low detection limit of 10 nM (S/N = 3). AIE-FMIPIL showed increased sensitivity and quenching efficiency compared with AIE-FMIP comprising a traditional monomer and cross-linker. AIE-FMIPIL exhibited selective binding to 4-NP because of the imprinted sites. AIE-FMIPIL was adopted to detect 4-NP in environmental samples.


Assuntos
Líquidos Iônicos , Corantes , Transferência Ressonante de Energia de Fluorescência , Nitrofenóis
17.
Acta Biochim Biophys Sin (Shanghai) ; 54(2): 243-251, 2022 01 25.
Artigo em Inglês | MEDLINE | ID: mdl-35130618

RESUMO

Hedgehog (Hh) signalling plays essential roles in regulating embryonic development and contributes to tumour initiation, growth and progression in multiple cancers. The detailed mechanism by which Hh signalling participates in tumour growth warrants thorough study, although several downstream target genes have been identified. Herein, a set of novel targets of Hh signalling was identified in multiple types of tumour cells via RNA-Seq analysis. Among these targets, the expression regulation and oncogenic function of the extracellular matrix component biglycan (BGN) were investigated. Further investigation verified that Hh signalling activates the expression of BGN via the transcription factor Gli2, which directly binds to the promoter region of BGN. Functional assays revealed that BGN facilitates tumour cell growth and proliferation in colorectal cancer (CRC) cells, and xenograft assays confirmed that BGN also promotes tumour growth . Moreover, analysis of clinical CRC samples showed that both the protein and mRNA levels of BGN are increased in CRC tissues compared to those in adjacent tissues, and higher expression of BGN is correlated with poorer prognosis of CRC patients, further confirming the function of BGN in CRC. Taken together, aberrantly activated Hh signalling increases the expression of BGN, possibly regulates the extracellular matrix, and thereby promotes tumour growth in CRC.


Assuntos
Neoplasias Colorretais , Proteínas Hedgehog , Biglicano/genética , Biglicano/metabolismo , Proliferação de Células/genética , Neoplasias Colorretais/genética , Neoplasias Colorretais/metabolismo , Matriz Extracelular/metabolismo , Feminino , Proteínas Hedgehog/genética , Humanos , Gravidez
18.
Sci Total Environ ; 825: 153686, 2022 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-35131245

RESUMO

Biochar plays an important role in controlling migration of pollutants in soils. However, little information is available on the interactions between soil-derived dissolved organic matter (DOM), biochar and soluble metal species. The aim of this work was to present the adsorption process of soil DOM by biochar (corn straw biochar produced at 700 °C) and to determine whether co-sorption of DOM would change the affinity for Pb(II). The adsorption rates of biochar and biochar + DOM for Pb(II) were best fitted with a pseudo-second order kinetic model, and the equilibrium adsorption isotherm data agreed well with both the Langmuir and Freundlich models. Adsorption of DOM to biochar reached equilibrium after 15 h with an uptake of 52% of the supplied DOM. We used fluorescence excitation-emission matrices (EEMs) with parallel factor (PARAFAC) analysis to demonstrate that protein-like, fulvic acid-like and humic acid-like substances were the primary constituents of the DOM, which were quenched over time in the presence of biochar. Synchronous fluorescence spectra indicated that the protein-like structures were the predominant fluorescence substances in DOM. Two-dimensional correlation spectroscopy (2D-COS) showed the binding of DOM to biochar resulted in the quenching of fluorescence in the order: protein-like substances > humic-like substances (280 > 355 nm). Data supports the notion that DOM can increase the adsorption capacity of biochar for metal-ions.


Assuntos
Chumbo , 2,5-Dimetoxi-4-Metilanfetamina , Carvão Vegetal , Substâncias Húmicas/análise , Solo/química , Espectrometria de Fluorescência/métodos
19.
Sci Total Environ ; 825: 153941, 2022 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-35189204

RESUMO

Pyrolysis is considered as a promising method to immobilize potentially toxic elements (PTEs) in animal manures. However, comparative study on characteristics and environmental risk of PTEs in biochar obtained by pyrolysis of animal manure at different reactors are lacking. In this study, swine manure was pyrolyzed at 300-600 °C in a lab-scale or pilot-scale reactor with the aim to investigate their effects on characteristics and environmental risk of As, Cd, Cu, Ni, Pb, and Zn in swine manure biochar. Results showed that biochars produced from pilot scale had lower pH and carbon (C) content but higher oxygen (O) content than those from lab scale. Biochars from pilot scale had higher total PTEs (except Cd) concentrations and releasable PTEs (except Pb) but lower CaCl2-extractable PTEs and phytotoxicity germination index (GI) to radish seedings than those from lab scale. Chemical speciation analysis indicated that PTEs in biochar produced from pilot-scale fast pyrolysis at 400 °C had higher percentage of more stable fraction (F5 fraction) and lower potential ecological risk index (RI) than those from lab-scale slow pyrolysis. These findings demonstrated that bioavailability and potential ecological risk of PTE in swine manure biochar were greatly decrease in the pilot-scale pyrolysis reactor and the optimum temperature was 400 °C considering the lowest potential ecological risk index.


Assuntos
Esterco , Pirólise , Animais , Cádmio , Carvão Vegetal/química , Chumbo , Esterco/análise , Suínos
20.
Nat Commun ; 13(1): 959, 2022 02 18.
Artigo em Inglês | MEDLINE | ID: mdl-35181650

RESUMO

Record rainfall and severe flooding struck eastern China in the summer of 2020. The extreme summer rainfall occurred during the COVID-19 pandemic, which started in China in early 2020 and spread rapidly across the globe. By disrupting human activities, substantial reductions in anthropogenic emissions of greenhouse gases and aerosols might have affected regional precipitation in many ways. Here, we investigate such connections and show that the abrupt emissions reductions during the pandemic strengthened the summer atmospheric convection over eastern China, resulting in a positive sea level pressure anomaly over northwestern Pacific Ocean. The latter enhanced moisture convergence to eastern China and further intensified rainfall in that region. Modeling experiments show that the reduction in aerosols had a stronger impact on precipitation than the decrease of greenhouse gases did. We conclude that through abrupt emissions reductions, the COVID-19 pandemic contributed importantly to the 2020 extreme summer rainfall in eastern China.


Assuntos
Aerossóis/análise , COVID-19/epidemiologia , Gases de Efeito Estufa/análise , Chuva , Emissões de Veículos/análise , China/epidemiologia , Inundações , Atividades Humanas/estatística & dados numéricos , Humanos , Pandemias/estatística & dados numéricos , SARS-CoV-2 , Estações do Ano
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