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1.
Phys Chem Chem Phys ; 25(41): 28141-28149, 2023 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-37818623

RESUMO

Spintronics is extremely important in the future development of information technology. Notably, two-dimensional carbon materials with atomically thick and p-electron systems have great potential for application in ultrathin spintronic devices. B-graphyne (B-GY) is a recently proposed two-dimensional carbon allotrope with double Dirac cones. It is a promising nanomaterial for high-speed spintronic devices due to its ultra-high Fermi velocity and thermodynamic stability. We tune the electronic and magnetic properties of B-GY by doping 3d transition metals (TM) (Cr, Mn, Fe, Co, Ni) based on first-principles calculations. After doping, TM forms strong covalent bonds (Fe, Co, Ni) and ionic bonds (Cr, Mn) with adjacent C atoms. The system of TM-doped B-GY (TM@B-GY) is transformed from a semimetal for B-GY to a metal (Cr, Mn, Fe, Co), but Ni@B-GY is still semimetal. Among them, Co@B-GY is approximately a half-metal. Moreover, TM (except Ni) can induce the magnetism of B-GY to undergo spin splitting. The TM d-orbitals are strongly coupled to the C p-orbitals, which play an important role in inducing magnetism. The results show that the tunable electronic and magnetic properties of TM@B-GY are promising as a high-speed spintronic device. Our research helps advance the study of semimetallic carbon allotropes in the field of spintronics.

2.
Ecotoxicol Environ Saf ; 202: 110887, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32585488

RESUMO

Chemical immobilization of heavy metals is a simple, low-cost, and environment-friendly technology for remediation of heavy metals contaminated soils. However, changes in environmental conditions, such as water management, acid deposition, temperature fluctuation, etc., might result in release of metal ions from the fixation sites, and the long-term stability of immobilization remediation is unclear. This study attempted to investigate the impact of water management strategies (wetting-drying cycle and dry cycle) on the stability of heavy metal immobilization by one-time application of biochar during 3 consecutive years of rice-wheat crop in Cu/Cd-contaminated soil. The transformation and accumulation of Cd and Cu in soil-crop system and the morphololgy and composition of biochar were analyzed. The results revealed that wetting-drying cycle and drying treatments reduced the contents of available Cd and Cu in soil by 15.9%-17.7% and 23.9%-31.5% and by 19.8%-62.7% and 16.1%-65.0%, as well as increased soil pH by 0.11-0.31 and 0.17-0.56, respectively. In the wetting-drying cycle treatment, biochar was more favorable for decrease in Cd and Cu accumulation in crop, when compared with that in dry treatment; however, the differences were insignificant in the subsequent years. Although the different water management strategies had no obvious effect on the soil total C, physicochemical analysis of the biochar collected after pot experiments indicated that the obvious structural decomposition of biochar in the drying treatment may have resulted in the release of heavy metals immobilized in biochar. These findings help in better understanding of the long-term immobilization mechanism of biochar in soil-plant system.


Assuntos
Agricultura/métodos , Cádmio/análise , Cobre/análise , Poluentes do Solo/análise , Carvão Vegetal/química , Poluição Ambiental/análise , Metais Pesados/análise , Oryza/química , Rotação , Solo/química , Triticum , Água/análise , Abastecimento de Água
3.
Ecotoxicol Environ Saf ; 168: 80-87, 2019 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-30384170

RESUMO

Global warming has become an important research topic in different disciplines around the world, especially in the fields of environment quality and food security. As a potential problem in soil environments, cadmium (Cd) contamination of rice under global warming conditions has not been thoroughly investigated. In this study, the fate of Cd in soil-rice systems under various warming patterns was studied via pot experiments under Free Air Temperature Increase (FATI) conditions. The patterns of warming included different temperatures (0.5 °C and 0.8 °C), different day-night durations (nighttime, daytime, and the whole day), and different warming stages (WSx) (including WS1 (seedling to tillering), WS2 (jointing to booting), WS3 (heading), WS4 (grain filling to milk ripening)). At harvest, samples of different rice tissues were collected and the Cd concentrations were measured. The results showed that warming significantly increased Cd concentrations in grain by 1.45 and 2.31 times, which was positively correlated with the two temperature increases (0.5 °C and 0.8 °C), respectively. Both daytime and nighttime warming significantly increased the Cd concentration in grain, and the daytime dominated Cd translocation from roots to shoots. In addition, warming in individual growth stages contributed to increases in Cd accumulation in grain by 31.6% (WS1), 15.0% (WS2), 20.6% (WS3), and 32.8% (WS4), respectively. Specifically, warming during the vegetative phase boosted Cd translocation from roots to shoots, while warming during maturation further increased Cd uptake and remobilization into grain. The projected results could provide a new and in-depth understanding of the fate of Cd in soil-rice systems under global warming conditions in Cd contaminated areas.


Assuntos
Cádmio/química , Temperatura Alta , Solo/química , Transporte Biológico , Cádmio/análise , Grão Comestível/química , Aquecimento Global , Oryza/efeitos dos fármacos , Raízes de Plantas/efeitos dos fármacos , Plântula/química , Poluentes do Solo/análise , Poluentes do Solo/química
4.
J Biochem Mol Toxicol ; 29(8): 382-7, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25917795

RESUMO

To investigate the effect of uric acid on the osteogenic and adipogenic differentiation of human bone mesenchymal stem cells (hBMSCs). The hBMSCs were isolated from bone marrow of six healthy donors. Cell morphology was observed by microscopy and cell surface markers (CD44 and CD34) of hBMSCs were analyzed by immunofluorescence. Cell morphology and immunofluorescence analysis showed that hBMSCs were successfully isolated from bone marrow. The number of hBMSCs in uric acid groups was higher than that in the control group on day 3, 4, and 5. Alizarin red staining showed that number of calcium nodules in uric acid groups was more than that of the control group. Oil red-O staining showed that the number of red fat vacuoles decreased with the increased concentration of uric acid. In summary, uric acid could promote the proliferation and osteogenic differentiation of hBMSCs while inhibit adipogenic differentiation of hBMSCs.


Assuntos
Adipogenia/efeitos dos fármacos , Células da Medula Óssea/efeitos dos fármacos , Células-Tronco Mesenquimais/efeitos dos fármacos , Osteogênese/efeitos dos fármacos , Ácido Úrico/farmacologia , Adulto , Células da Medula Óssea/citologia , Células da Medula Óssea/fisiologia , Imunofluorescência , Humanos , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/fisiologia , Adulto Jovem
5.
Zhongguo Zhong Yao Za Zhi ; 40(20): 4037-43, 2015 Oct.
Artigo em Zh | MEDLINE | ID: mdl-27062824

RESUMO

Effect of ginsenoside total saponin (GTS) on the regulation of P450 of livers of rats after γ-ray irradiation was studied. Rats were irradiated by the 6°Coγ-ray for one-time dose of 5.5 Gy, dose rate of 117.1-119.2 cGy. The cocktail probe, qPCR and Western blot were used to detect expression of enzymatic activites, mRNA and protein of rats. Contrasted with blank group, expression of CYP1A2, 2B1, 2E1, 3A4 of irradiation group showed a up-regulated (P < 0.05). Contrasted with irradiation group, exprression of CYP1A2, 2B1, 2E1, 3A4 of GTS group showed a downward trend. GTS had negative agonistic action against expression of P450 of rats by irradiatied.


Assuntos
Sistema Enzimático do Citocromo P-450/metabolismo , Medicamentos de Ervas Chinesas/farmacologia , Ginsenosídeos/farmacologia , Fígado/efeitos dos fármacos , Fígado/efeitos da radiação , Panax/química , Animais , Sistema Enzimático do Citocromo P-450/genética , Raios gama , Fígado/enzimologia , Masculino , Microssomos Hepáticos/efeitos dos fármacos , Microssomos Hepáticos/enzimologia , Ratos , Ratos Wistar
6.
Chemosphere ; 363: 142873, 2024 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-39019187

RESUMO

Electro-osmosis has been valued as a promising technology to enhance the dewatering of waste sludge, stabilization and environmental remediation of soils with low permeability. However, the coefficient of electro-osmotic permeability (keo) is commonly taken as constant value which is particularly not the case in variable charge soil. As a result, the nonlinearity of the electro-osmotic flow (EOF) and the direction reverse could not be interpreted. Herein, the electro-chemical parameters were monitored in electro-osmotic experiment with natural variable charge soil. It was observed that the evolutions showed significant nonlinear behavior and were correlated. The comprehensive Zeta potential model proposed by the authors was applied to simulate the nonlinear keo induced by the variable pH and electrolyte concentration. The agreement between tested and simulated flow rate variation and excess pore water pressure distribution demonstrated the reliability of the theory. The error rate of the simulations through coupling nonlinear keo and voltage gradient Ex was reduced to 29.4% from 381.9% of calculations with constant parameters. The direction reverse of EOF was innovatively interpreted. Hence, the numerical model would act as a useful tool to connect these electro-chemical parameters and provide guidance to evaluate contributions of commonly used pH conditioning measurements.

7.
J Chem Phys ; 138(3): 034307, 2013 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-23343276

RESUMO

We demonstrate the ratchet and phase locking effects in a two-dimensional overdamped Frenkel-Kontorova model with a square symmetric periodic substrate when both a longitudinal dc drive and a circular ac drive are applied. Besides the harmonic steps, the large half integer steps can also clearly be seen in the longitudinal (x) direction. These half integer steps are directly correlated to the appearance of positive and negative ratchet effects in the transverse (y) direction due to the symmetry breaking in the combination of the dc and ac drives. The angle between the net displacement and the longitudinal direction is analytically obtained in a single period of the ac drive. In the examination of the amplitude dependence of the ac drive, the maxima decrease monotonically with the amplitude, while the anomalies occur for the critical depinning force and the harmonic steps due to the spatial symmetry breaking of orbits in the presence of the ac drive.

8.
Zhonghua Yi Xue Za Zhi ; 93(37): 2993-6, 2013 Oct 08.
Artigo em Zh | MEDLINE | ID: mdl-24401593

RESUMO

OBJECTIVE: To establish a goat model of acute spinal cord compression injury through a modified percutaneous technique with a Foley double-lumen urine catheter and explore the method feasibility and preliminary observation. METHODS: Twelve adult male Chongming goats were randomly divided into 3 groups:control (A, n = 4), 0.5 ml compression (B, n = 4) and 1 ml compression (C, n = 4). After local anesthesia, all animals received epidural balloon catheter (5Fr) insertion via a percutaneous trans-lumbosacral interlaminar space technique that mimicked the method used in vascular access for angiography. The balloon catheter was advanced under fluoroscopic guidance until its distal tip reached the middle of T6 level.One week later, for groups B and C, the balloon was inflated by half-strength contrast material, 0.5 ml and 1 ml, respectively. The balloon was left inflated for 30 min and then deflated. The images of computed tomography (CT) and magnetic resonance (MR) were taken before and after surgical procedures.Quantitative assessment of spine canal occupying rate was accomplished by an off-line software program based on CT results. Motor function was assessed by the modified Tarlov scale. Two animals of each group were sacrificed after a total observation period of 48 h and 72 h respectively.Spinal cords from the injured level were then obtained for pathologic examinations. RESULTS: All animals underwent successful catheterization occupying 6.8%±0.7% (Group A), 6.7%±0.7% (Group B) and 6.6%±0.6% (Group C) of spine canal respectively. After inflation, the occupying rate of groups B and C achieved 43.4%±2.5% and 88.1%±2.3% respectively.Ventral compression of spinal cord was noted on MR images.Hindlimb movement remained normal after catheter insertion in all groups. All animals in group B and C became paraplegic after inflation. And a positive correlation existed between injection volume and Tarlov score. Pathological findings confirmed neuron atrophy, increased gap around neurons, mild demyelination and vacuolar degeneration both in groups B and C at 48 h after injury. Pathological changes deteriorated at 72 h after injury. CONCLUSION: The results of behavioral evaluation, radiographic images and pathological examination reveal an evidence of acute spinal cord injury. Percutaneous epidural balloon catheter insertion differs from previous techniques by avoiding surgical exposure and associated artifacts, yet it offers injury mechanisms similar to those of human spinal cord injury. As a new means of modeling spinal cord injury in animals, this technique has many potential applications.


Assuntos
Modelos Animais de Doenças , Compressão da Medula Espinal , Traumatismos da Medula Espinal , Animais , Cateterismo/efeitos adversos , Cabras , Masculino
9.
J Hazard Mater ; 453: 131396, 2023 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-37058937

RESUMO

Persulfate-based electrokinetic (EK) chemical oxidation appears to be a novel and viable strategy for the in situ remediation of polycyclic aromatic hydrocarbons (PAHs) polluted soil; however, the possible toxic byproducts of PAHs have been overlooked. In this study, we systematically investigated the formation mechanism of the nitro-byproducts of anthracene (ANT) during the EK process. Electrochemical experiments revealed that NH4+ and NO2- originating from nitrate electrolyte or soil substrates were oxidized to NO2• and NO• in the presence of SO4•-. Liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS/MS) analysis with 15N labeling revealed the formation of nitro-byproducts (14 kinds), including 1-hydroxy-4-nitro-anthraquinone and its similar derivatives, 4-nitrophenol, and 2,4-dinitrophenol. The nitration pathways of ANT have been proposed and described, mainly including the formation of hydroxyl-anthraquinone-oxygen and phenoxy radicals and the subsequent addition of NO2• and NO•. ANT-based formation of nitro-byproducts during EK, which is usually underestimated, should be further investigated due to their enhanced acute toxicity, mutagenic effects, and potential threat to the ecosystem.

10.
Environ Sci Technol ; 46(5): 2738-45, 2012 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-22316080

RESUMO

Hydroxyapatite nanoparticles (nHAP) have been widely used to remediate soil and wastewater contaminated with metals and radionuclides. However, our understanding of nHAP transport and fate is limited in natural environments that exhibit significant variability in solid and solution chemistry. The transport and retention kinetics of Alizarin red S (ARS)-labeled nHAP were investigated in water-saturated packed columns that encompassed a range of humic acid concentrations (HA, 0-10 mg L(-1)), fractional surface coverage of iron oxyhydroxide coatings on sand grains (λ, 0-0.75), and pH (6.0-10.5). HA was found to have a marked effect on the electrokinetic properties of ARS-nHAP, and on the transport and retention of ARS-nHAP in granular media. The transport of ARS-nHAP was found to increase with increasing HA concentration because of enhanced colloidal stability and the reduced aggregate size. When HA = 10 mg L(-1), greater ARS-nHAP attachment occurred with increasing λ because of increased electrostatic attraction between negatively charged nanoparticles and positively charged iron oxyhydroxides, although alkaline conditions (pH 8.0 and 10.5) reversed the surface charge of the iron oxyhydroxides and therefore decreased deposition. The retention profiles of ARS-nHAP exhibited a hyperexponential shape for all test conditions, suggesting some unfavorable attachment conditions. Retarded breakthrough curves occurred in sands with iron oxyhydroxide coatings because of time-dependent occupation of favorable deposition sites. Consideration of the above effects is necessary to improve remediation efficiency of nHAP for metals and actinides in soils and subsurface environments.


Assuntos
Antraquinonas/química , Durapatita/química , Compostos Férricos/química , Substâncias Húmicas/análise , Movimento (Física) , Nanopartículas/química , Dióxido de Silício/química , Eletricidade , Meio Ambiente , Hidrodinâmica , Concentração de Íons de Hidrogênio , Cinética , Nanopartículas/ultraestrutura , Tamanho da Partícula , Coloração e Rotulagem
11.
Chemosphere ; 286(Pt 1): 131595, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34293572

RESUMO

Because of the high hydrophobicity, low volatility, and high sorption capacity of PAHs, their remediation in contaminated soil is challenging. Electrokinetic (EK) enhanced chemical remediation is an emerging dual technology employed in this study, using a new oxidant peroxymonosulfate (PMS) to remediate PAHs contaminated soil. Here, PMS migration under electric field and the remediation efficiency for the PAHs polluted soil were assessed. We observed that the PMS removal efficiencies (59.7%-82.8%) were higher than those with persulfate (PS) (53.9%-78.5%), indicating PMS's superior oxidation capacity for PAHs. Although oxidant PMS can decontaminate PAHs in polluted soils, its removal of PAHs was only 11.0% without the enhanced methods. The enhancements increased the removal efficiency for PAHs from 0.33 to 2.10 times. At fixed catholyte pH of 4, the highest removal efficiency (34.1%) was achieved because it enhanced PMS migration from cathode to anode. These findings suggested that PMS was a potential oxidant for EK remediation, and some enhancements must be applied in EK combined PMS remediation PAHs polluted soil.


Assuntos
Recuperação e Remediação Ambiental , Poluentes do Solo , Peróxidos , Solo , Poluentes do Solo/análise
12.
Environ Sci Pollut Res Int ; 29(59): 88989-89001, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35841503

RESUMO

Electrokinetic (EK) remediation technology can enhance the migration of reagents to soil and is especially suitable for in situ remediation of low permeability contaminated soil. Due to the long aging time and strong hydrophobicity of polycyclic aromatic hydrocarbons (PAHs) from historically polluted soil, some enhanced reagents (oxidant, activator, and surfactant) were used to increase the mobility of PAHs, and remove and degrade PAHs in soil. However, under the electrical field, there are few reports on the roles and combined effect of oxidant, activator, and surfactant for remediation of PAHs historically contaminated soil. In the present study, sodium persulfate (PS, oxidant, 100 g L-1) or/and Tween 80 (TW80, surfactant, 50 g L-1) were added to the anolyte, and citric acid chelated iron(II) (CA-Fe(II), activator, 0.10 mol L-1) was added to catholyte to explore the roles and contribution of enhanced reagents and combined effect on PAHs removal in soil. A constant voltage of 20 V was applied and the total experiment duration was 10 days. The results showed that the removal rate of PAHs in each treatment was PS + CA-Fe(II) (21.3%) > PS + TW80 + CA-Fe(II) (19.9%) > PS (17.4%) > PS + TW80 (11.4%) > TW80 (8.1%) > CK (7.5%). The combination of PS and CA-Fe(II) had the highest removal efficiency of PAHs, and CA-Fe(II) in the catholyte could be transported toward anode via electromigration. The addition of TW80 reduced the electroosmotic flow and inhibited the transport of PS from anolyte to the soil, which decreased the removal of PAHs (from 17.4 to 11.4% with PS, from 21.3 to 19.9% with PS+CA-Fe(II)). The calculation of contribution rates showed that PS was the strongest enhancer (3.3~9.9%), followed by CA-Fe(II) (3.9~8.5%) (with PS), and the contribution of TW80 was small and even negative (-1.4~0.6%). The above results indicated that the combined application of oxidant and activator was conducive to the removal of PAHs, while the addition of surfactant reduced the EOF and the migration of oxidant and further reduced the PAHs removal efficiency. The present study will help to further understand the role of enhanced reagents (especially surfactant) during enhanced EK remediation of PAHs historically contaminated soil.


Assuntos
Recuperação e Remediação Ambiental , Hidrocarbonetos Policíclicos Aromáticos , Poluentes do Solo , Hidrocarbonetos Policíclicos Aromáticos/análise , Poluentes do Solo/análise , Tensoativos , Oxidantes , Solo , Compostos Ferrosos
13.
J Hazard Mater ; 428: 128273, 2022 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-35051774

RESUMO

Electrokinetic-Fenton (EK-Fenton) technology requires a high dose of H2O2 to produce •OH radicals, which adds a high cost to the remediation process and raises safety concerns during transportation and storage of H2O2. Moreover, the remediation efficiency of the conventional EK-Fenton process is low due to the meaningless consumption of H2O2 on the electrodes and the alkaline environment near the cathode. In this work, a modified CMK3-gas diffusion electrode (CMK3-GDE) is fabricated. This cathode can continuously generate H2O2, and the cumulative H2O2 concentration can reach 0.23 M during 10 days of the test. The utilization of cation exchange membranes (CEMs) efficiently restricts the decomposition of H2O2 on the electrodes and prevents the alkalization of the soil near the cathode, resulting in a 13.7-43.2% increase of the removal efficiency of polycyclic aromatic hydrocarbons (PAHs). In this new treatment process, PAHs are mainly oxidized into quinones, ketones, alcohols, and small molecule acids, and all these products have lower toxicities than PAHs. The EK-Fenton/CMK3-GDE-CEM system exhibits excellent remediation efficiency for treating PAHs polluted soil, which could be a sustainable, eco-friendly, and low-cost strategy for soil remediation.


Assuntos
Recuperação e Remediação Ambiental , Hidrocarbonetos Policíclicos Aromáticos , Poluentes do Solo , Eletrodos , Peróxido de Hidrogênio , Solo , Poluentes do Solo/análise
14.
J Hazard Mater ; 433: 128724, 2022 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-35398794

RESUMO

Electrokinetic in-situ chemical oxidation (EK-ISCO) has attracted much attention during remediation of organic contaminated soil. Oxidants in EK-ISCO brings high cost and negative effects on soil physicochemical properties. In this study, a novel approach of combined electrokinetic treatment and anode oxidation was investigated to remediate phenanthrene polluted soils without adding oxidants. The fabricated Ti4O7 acted as anode, and could generate •OH at the rate of 9.31 × 10-7 mol h-1 at current 5.10 mA cm-2 through direct H2O electrolysis. Electro-osmotic flow (EOF) was used to transport phenanthrene to anode for the subsequent degradation. Sandy soil, fluvo-aquic soil and red soil were selected as typical soil samples, because pH and buffer capacity were two important factors affecting the direction of EOF. Strategies were developed to regulate the direction of EOF, including adding CEM membrane, maintaining soil pH at 3.5-4.0 and mixing solution from anode and cathode chambers. After treatment, more than 81.9% of phenanthrene was removed without adding any oxidants, and the remediated soil had low toxicity for Lolium perenne growth based on 3-d cultivation results. The results indicated that EK-AO had the advantage of less energy consumption and superior environmental friendliness than traditional EK-ISCO.


Assuntos
Recuperação e Remediação Ambiental , Poluentes do Solo , Eletrodos , Indicadores e Reagentes , Oxidantes , Fenantrenos , Solo , Poluentes do Solo/análise
15.
Chemosphere ; 263: 128085, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33297083

RESUMO

Soil contaminated by combinations of heavy metals and organic pollutants has become an increasingly prominent environmental issue. Developing efficient technologies to synchronously decontaminate such co-contaminated sites is challenging and imperative. In our previous study for the treatment of Copper (Cu) and pyrene contaminated soil, electrokinetics (EK) coupled acidic permanganate (PM) performed best for degradation of pyrene near the injection spot, but it unfortunately prevented the migration of Cu. In order to further enhance the removal efficiency of these contaminants, in this study, batch experiments were conducted to investigate the feasibility of delivering PM by EK under regular refreshment of acidoxidant along with amplification of voltage gradient. The results showed that PM can be transported from cathode to anode to S2 section (near the anode) with a slow mass transfer rate via electromigration and reversed electroosmotic flow, and further delivery was achieved when Cu and pyrene were coexisted. The reaction of pyrene with PM produced a lower soil pH condition, which was conductive to the transport of Cu, and the existence of Cu promoted the migration of PM. The coexistence of Cu and pyrene favored the removal efficiency of the pollutants, and 92.8% of Cu and 70.7% of pyrene were removed after 15 d EK treatment. Thus, EK + acidic PM with regularly supplement of oxidant is appropriate to achieve complete mass depletion of heavy metals and PAHs, especially in low buffered soils.


Assuntos
Recuperação e Remediação Ambiental , Poluentes do Solo , Cobre/análise , Permanganato de Potássio , Pirenos/análise , Solo , Poluentes do Solo/análise
16.
Environ Sci Pollut Res Int ; 27(35): 44355-44367, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32770336

RESUMO

Electrokinetic (EK) remediation combined with in situ chemical oxidation (ISCO) can be applied to low permeability organic contaminated soil. However, the effects of electrode configuration on EK-oxidation remediation remain unclear. In this study, EK-ISCO remediation of real polycyclic aromatic hydrocarbon (PAH)-contaminated soil under different electrode configurations was conducted. The results showed that increasing the number of anodes and electrode pairs in one-dimensional (1D) and two-dimensional (2D) electrode configuration was conducive to migration of oxidants into the system. The change in soil pH after remediation in 2D electrode configuration was not obvious, but the increase of soil electrical conductivity (EC) was higher than that of the 1D electrode configuration. The removal rates of PAHs in 2D electrode configurations (35.9-40.9%) were relatively higher than those of the 1D electrode configurations (0.54-31.6%), and the hexagonal electrode configuration yielded the highest pollutant removal efficiency, reaching 40.9%. The energy consumption under 2D electrode configuration was smaller than that under 1D electrode configuration, and the energy consumption of per gram removed PAHs in the hexagon configuration (66.74 kWh (g PAHs)-1) was lowest in all electrode configurations. Overall, the results of this study suggest that 2D electrode configuration is better than 1D and hexagonal electrode configuration is an optimal electrode configuration.


Assuntos
Recuperação e Remediação Ambiental , Hidrocarbonetos Policíclicos Aromáticos , Poluentes do Solo , Eletrodos , Oxirredução , Solo
17.
J Hazard Mater ; 382: 121042, 2020 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-31450203

RESUMO

Electrokinetic in situ chemical oxidation (EK-ISCO) could be used to remediate inorganic/organic-contaminated soil. Oxidizing agents were effectively delivered to the contaminated zones through electromigration and the electroosmosis. However, the cathode may react with oxidants, which would reduce the oxidative effect and lead to low contaminant removal rates. In this study, ion-exchange membranes (IEMs) enhanced EK-ISCO was used to remediate polycyclic aromatic hydrocarbons (PAHs) in contaminated soil. IEMs were installed between the electrode compartment and the soil compartment. The results showed that the IEMs could effectively control pH and the oxidation-reduction potential (ORP) changes in the soil column. Placing a cation-exchange membrane (CEM) at the cathode prevented the S2O82- from contacting the cathode and reduced the oxidative loss effect, which meant that PAH removal efficiency significantly improved (from 33.1% to 87.1%). Furthermore, there were minimal changes to the soil properties. Maintaining the soil at a low pH also improved the PAH removal efficiency (93.1%), but the physicochemical properties of the soil significantly changed and a large amount of power was consumed (2015 kWh t-1). This study indicated that placing a CEM at the cathode improved remediation efficiency, and reduced power consumption and the adverse effects on soil properties during EK-ISCO.

18.
Chemosphere ; 243: 125439, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31995887

RESUMO

This paper introduces a novel method for ethylenediaminetetraacetic acid (EDTA)-enhanced electrokinetic (EK) remediation by combining dual cation-exchange membranes and circulation methods for an aged electroplating soil contaminated by chrome (Cr), copper (Cu), and nickel (Ni). Three laboratory-scale EK experiments were carried out, including T1, the traditional EK process; T2, the traditional EDTA-enhanced EK process; and T3, the assisted EDTA-enhanced EK process. The results obtained show that removal of Cu and Ni in T3 was 3-10 times higher than after T1 and T2. However, the removal of Cr (total) was small in all experiments because of the high content of Cr(III). T3 eliminated the metal accumulation problem that existed for T1 and T2. Simultaneously, the highly acidified area (pH < 4) was reduced from 80% in T1 and T2 to only 20% in T3. The results obtained in T3 indicate that the chelating effect of EDTA has a greater ability to dissolve oxidizable Cu and Ni in the soil than the acidification effect. Toxicity evaluation confirmed that the soil treated by T3 presented a lower effect on a luminescent bacterium (Photobacterium phosphoreum T3) because soil pH tended to be more neutral after this treatment. This research provides a novel method for removing heavy metals from soil in a more environmentally friendly way and clarifies the cause of the existing problems of low removal efficiency and high accumulation in the traditional EK process.


Assuntos
Técnicas Eletroquímicas/métodos , Recuperação e Remediação Ambiental/métodos , Resinas de Troca de Cátion , Compostos de Cromo/isolamento & purificação , Cobre/química , Cobre/isolamento & purificação , Ácido Edético/química , Galvanoplastia , Metais Pesados/isolamento & purificação , Níquel/isolamento & purificação , Solo/química , Poluentes do Solo/isolamento & purificação
19.
J Hazard Mater ; 384: 121452, 2020 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-31676167

RESUMO

Appraising cadmium (Cd) phytoavailability and transfer in soil-plant system is imperative and it requires timely and accurate monitoring of Cd to ensure food safety. However, ambiguities regarding the factors regulating Cd mobility and transfer in soil-plant system makes understanding of Cd accumulation mechanism in wheat grain challenging. In present study, we attempted to explore the interrelationship among soil-plant-N management factors governing Cd transfer from soil-to-wheat grain and to provide a novel and alternative approach for grain Cd prediction. For this purpose, we established the allometric relationships of wheat phenology (plant dry matter at different growth stages and grain yield) with grain Cd concentration and soil properties (pH, EC, Eh, and CEC) under varied N rates experiment and investigated the interactions among aforementioned factors. The newly established allometric relationships demonstrated that plant phenology and yield were positively correlated with grain Cd concentration (R2 = 0.86-0.95) and soil properties (R2 = 0.84-0.97). Robust interrelationship among soil-plant-N management factors indicated that Cd transfer from soil-to-wheat grain was potentially co-regulated by their interactive effect. Findings will assist to strategize crop productivity and soil sustainability without compromising food safety. Further studies are imperative to better understand the Cd uptake mechanism in different wheat cultivars and management practices.


Assuntos
Cádmio/metabolismo , Grão Comestível/efeitos dos fármacos , Nitrogênio/farmacologia , Poluentes do Solo/metabolismo , Triticum/efeitos dos fármacos , Agricultura/métodos , Disponibilidade Biológica , Grão Comestível/crescimento & desenvolvimento , Grão Comestível/metabolismo , Fertilizantes , Solo/química , Triticum/crescimento & desenvolvimento , Triticum/metabolismo
20.
Orthop Surg ; 12(4): 1261-1269, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32558266

RESUMO

OBJECTIVE: To explore the molecular regulatory mechanisms underlying fibroblast differentiation and dysfunction in the development of adolescent idiopathic scoliosis (AIS) in an effort to identify candidate therapeutic targets for AIS. METHODS: The GSE110359 dataset, obtained from the bone marrow stromal cells of 12 AIS patients and five healthy controls, was retrieved from the GEO database. The data were preprocessed and differentially expressed genes (DEGs) were identified. KEGG pathway and Gene Ontology (GO)-Biological Process (BP) enrichment analyses were performed to identify the function of the DEGs. A protein-protein interaction (PPI) and a microRNA-transcription factor (TF)-target co-regulatory network were constructed to identify hub genes in the development of AIS. In addition, hub DEGs were evaluated by quantitative PCR (qPCR) and immunohistochemical staining. RESULTS: A total of 188 DEGs including 100 up-regulated and 88 down-regulated genes were obtained. The up-regulated DEGs were related to "p53 signaling pathway", "FoxO signaling pathway", and "cGMP-PKG signaling pathway" terms, while the down-regulated DEGs were significantly enriched in seven terms including "protein processing in endoplasmic reticulum". The key up-regulated genes, PRKG1, CCNG2, and KAT2B, and the key down-regulated genes, MAP2K1 and DUSP6, were identified by the PPI and miRNA-TF-Target regulatory network analyses. mRNA expression patterns for PRKG1, DUSP6, and KAT2B were successfully verified by qPCR. In addition, PRKG1 protein levels were found to be elevated during the immunohistochemical analysis. CONCLUSION: Increased expression of PRKG1 in AIS patients might be an attractive therapeutic target for AIS. However, further gain or loss-of-function studies should be conducted.


Assuntos
Proteínas Quinases Dependentes de GMP Cíclico/metabolismo , Fibroblastos/metabolismo , MicroRNAs/metabolismo , Escoliose/enzimologia , Adolescente , Expressão Gênica , Humanos , Células-Tronco Mesenquimais , Mapas de Interação de Proteínas , Escoliose/genética , Regulação para Cima
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