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1.
Endocr Pract ; 2024 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-39214463

RESUMO

OBJECTIVE: Previous meta-analyses have investigated the effects of isoflavones on bone metabolism in perimenopausal or postmenopausal women. However, there were still conflicting results. Thereby, this umbrella review assessed the existing meta-analysis evidence of the effects of isoflavone interventions on bone metabolism in perimenopausal and postmenopausal women. METHODS: This study was conducted following the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). From the inception until August 24, 2023, PubMed, Embase, Cochrane, and Web of Science databases were searched to identify meta-analyses of randomized controlled trials (RCTs). The outcomes included bone mineral densities (BMDs), and bone turnover markers (BTMs) of osteocalcin (OC), bone-specific alkaline phosphatase (BAP), pyridinoline (PYD), deoxypyridinoline (DPD), Procollagen Type 1 N-Terminal Propeptide (P1NP), and C-telopeptide of Type 1 Collagen (CTX). The random-effects model was used to recalculate the extracted effect sizes. Mean difference (MD) was used as a summary effect measure. RESULTS: Ten meta-analyses of RCTs were included. The isoflavone intervention was associated with increased BMDs in lumbar spine (MD: 11.50 mg/cm2, 95% confidence interval (CI): 6.46 to 16.55), femoral neck (MD: 2.03%, 95% CI: 0.57 to 3.50), and top hip (MD: 0.31%, 95% CI: 0.03 to 0.59) in perimenopausal and postmenopausal women. CONCLUSION: Our findings indicate that isoflavone interventions have the potential to improve BMD at different bone sites, including the lumbar spine, femoral neck, and total hip in perimenopausal and postmenopausal women. Isoflavone may be considered a complementary option in the bone loss of perimenopausal and postmenopausal women.

2.
J Med Chem ; 67(11): 9091-9103, 2024 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-38778566

RESUMO

Induction of cuproptosis and targeting of multiple signaling pathways show promising applications in tumor therapy. In this study, we synthesized two thiosemicarbazone-copper complexes ([CuII(L)Cl] 1 and [CuII2CuI(L)2Cl3] 2, where HL is the (E)-N-methyl-2-(phenyl(pyridin-2-yl)methylene ligand), to assess their antilung cancer activities. Both copper complexes showed better anticancer activity than cisplatin and exhibited hemolysis comparable to that of cisplatin. In vivo experiments showed that complex 2 retarded the A549 cell growth in a mouse xenograft model with low systemic toxicity. Primarily, complex 2 kills lung cancer cells in vitro and in vivo by triggering multiple pathways, including cuproptosis. Complex 2 is the first mixed-valent Cu(I/II) complex to induce cellular events consistent with cuproptosis in cancer cells, which may stimulate the development of mixed-valent copper complexes and provide effective cancer therapy.


Assuntos
Antineoplásicos , Complexos de Coordenação , Cobre , Neoplasias Pulmonares , Tiossemicarbazonas , Tiossemicarbazonas/química , Tiossemicarbazonas/farmacologia , Tiossemicarbazonas/síntese química , Tiossemicarbazonas/uso terapêutico , Humanos , Cobre/química , Animais , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/patologia , Antineoplásicos/farmacologia , Antineoplásicos/química , Antineoplásicos/síntese química , Antineoplásicos/uso terapêutico , Complexos de Coordenação/farmacologia , Complexos de Coordenação/química , Complexos de Coordenação/síntese química , Complexos de Coordenação/uso terapêutico , Camundongos , Camundongos Nus , Adenocarcinoma de Pulmão/tratamento farmacológico , Adenocarcinoma de Pulmão/patologia , Linhagem Celular Tumoral , Adenocarcinoma/tratamento farmacológico , Adenocarcinoma/patologia , Células A549 , Proliferação de Células/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto , Transdução de Sinais/efeitos dos fármacos , Relação Estrutura-Atividade , Hemólise/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Camundongos Endogâmicos BALB C
3.
J Hazard Mater ; 472: 134537, 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38759279

RESUMO

Experimental studies assessed the removal efficiency and fine-size distribution of CPM coupled with compositional analysis across air pollution control device systems (APCDs) at an ultra-low emission (ULE) power plant. The findings indicated total CPM emissions were reduced to a minimum of 0.418 mg/m3 at the Wet Electrostatic Precipitator (WESP). The Wet Flue Gas Desulfurization (WFGD) showed the highest removal efficiency (98%) across all particle sizes, notably in the ultra-micron range. Selective Catalytic Reduction (SCR) demonstrated a mere 34% overall efficiency, with a negative removal rate in the ultra-fine particle range. The WESP effectively removed CPM only in sub-micron and ultra-micron sizes, but significantly increased water-soluble ions formation in ultra-fine spatially suspended CPM (CPMspa), leading to overall negative efficiency. Thus, the removal efficiency of the ultra-fine particle range was most affected among the three particle size ranges when the flue gas went through the APCDs. Major metal elements and water-soluble ions were more readily removed by APCDs due to their surface aggregation, while the removal of trace elements like Hg and Se was limited. Reducing SO42-/NH4+ formation in SCR, and optimizing WESP spray system operations based on flue gas components are essential steps in controlling CPM concentration in ULE power plants.

4.
BMC Pregnancy Childbirth ; 24(1): 123, 2024 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-38341545

RESUMO

BACKGROUND: Uterine leiomyomas are hormone-dependent benign tumors and often begin to shrink after menopause due to the reduction in ovarian steroids. The influence of pregnancy on uterine leiomyomas size remains unclear. Here, we present a case of spontaneous regression of a giant uterine leiomyoma after delivery. CASE PRESENTATION: A 40-year-old woman presented with multiple uterine leiomyomas, one of which is a giant uterine leiomyomas (approximately 8 cm in diameter) that gradually shrinked after delivery. At over two months postpartum, the large myometrial leiomyoma had transformed into a submucosal leiomyoma, and over 3 years postpartum, both the submucosal leiomyoma and multiple intramural leiomyomas completely regressed. CONCLUSION: Spontaneous regression of a giant uterine leiomyom is rare after delivery. Considering uterine leiomyoma regression until over 3 year postpartum,we need to observe the regression of uterine fibroid for a longer time postpartum in the absence of fibroid related complications. In addition, it will provide new insights for treatment options of uterine leiomyomas in the future.


Assuntos
Leiomioma , Neoplasias Uterinas , Gravidez , Feminino , Humanos , Adulto , Remissão Espontânea , Leiomioma/complicações , Neoplasias Uterinas/complicações , Útero/patologia , Período Pós-Parto
5.
Neurosci Bull ; 39(5): 745-758, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36587114

RESUMO

Diabetic neuropathic pain (DNP) is the most common disabling complication of diabetes. Emerging evidence has linked the pathogenesis of DNP to the aberrant sprouting of sensory axons into the epidermal area; however, the underlying molecular events remain poorly understood. Here we found that an axon guidance molecule, Netrin-3 (Ntn-3), was expressed in the sensory neurons of mouse dorsal root ganglia (DRGs), and downregulation of Ntn-3 expression was highly correlated with the severity of DNP in a diabetic mouse model. Genetic ablation of Ntn-3 increased the intra-epidermal sprouting of sensory axons and worsened the DNP in diabetic mice. In contrast, the elevation of Ntn-3 levels in DRGs significantly inhibited the intra-epidermal axon sprouting and alleviated DNP in diabetic mice. In conclusion, our studies identified Ntn-3 as an important regulator of DNP pathogenesis by gating the aberrant sprouting of sensory axons, indicating that Ntn-3 is a potential druggable target for DNP treatment.


Assuntos
Diabetes Mellitus Experimental , Neuropatias Diabéticas , Neuralgia , Camundongos , Animais , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Experimental/metabolismo , Axônios/fisiologia , Células Receptoras Sensoriais/metabolismo , Neuralgia/metabolismo
6.
Environ Pollut ; 302: 119107, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35248619

RESUMO

3D hierarchical porous biochar (HPBC) was synthesized by a thermally removable template without post-activation. Zn(NO3)2 decomposition produced gases and ZnO in situ to activate and expand the three-dimensional micro-and mesopores. Compared with pristine biochar (BC), the specific surface area and pore volume of HPBC were increased by 223 and 75 times, respectively. The abundant pore structure of HPBC significantly enhanced the diffusion rate of heavy metals. For example, compared to BC, the time required for HPBC to adsorb Pb2+ reach adsorption equilibrium was reduced by 87.5% (40 min vs 5min). Such an adsorption performance of HPBC was also insensitive to different background ions (K+, Na+, Ca2+, and Mg2+) with a much higher concentration than that of heavy metals. When applied to treat desulfurization wastewater from power plants, HPBC yielded 100% removal of Pb2+ and Cd2+, much higher than that by using commercial activated carbon (28%). Molecular dynamics simulation revealed different locations preferred by the adsorption of Pb2+ (micropores) and Cd2+ (mesopores) in the hierarchical pore structures. The adsorption of Pb2+ and Cd2+ on HPBC was mainly achieved by diffusion, oxygen functional group complexation, and precipitation. These results provided better knowledge to understand the microscopic adsorption mechanisms of heavy metals in hierarchical pores and a facile yet robust strategy to design such structures in biochar for efficient wastewater treatment.


Assuntos
Poluentes Químicos da Água , Óxido de Zinco , Adsorção , Cádmio/química , Carvão Vegetal/química , Chumbo , Simulação de Dinâmica Molecular , Porosidade , Águas Residuárias , Poluentes Químicos da Água/análise
7.
Environ Sci Pollut Res Int ; 29(29): 44709-44722, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35133594

RESUMO

Coal ash has emerged as an important alternative source for rare earth elements (REEs). The enrichment and occurrence form of REEs among coal combustion products are of great significance for both technical design and economic evaluation of recovering REEs from the coal ash. Here, the enrichment and occurrence form of REEs in the ash were investigated. Compared with ashes from muffle furnace, coal fly ash (CFA) from power plants involved higher enrichment ratio of REEs, which was explained by the fractionation of coal ashes to concentrate REEs in finer CFA, higher combustion temperature to vaporize more volatile elements, and longer residence time of fly ash to absorb REEs in the gas. In addition, CFA samples were analyzed by sequence chemical extraction procedure (SCEP) and scanning electron microscope with an energy dispersive spectrometer (SEM-EDX), which revealed the important role of aluminum in the occurrence form of REEs compared with Si in aluminosilicates of CFA. This conclusion was further confirmed by thermodynamic equilibrium calculation, which also agreed qualitatively with the observation that REEs mainly existed in the solid phase. Both experimental and computational results of this work provided insights to understand the distribution of REEs in CFA and optimize their extraction processes.


Assuntos
Carvão Mineral , Metais Terras Raras , Fracionamento Químico , Carvão Mineral/análise , Cinza de Carvão/análise , Centrais Elétricas
8.
Sci Total Environ ; 787: 147597, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-33992943

RESUMO

Particle-bound mercury discharged with fine particulate matter from coal-fired power plants causes atmospheric pollution that impacts human health. In this study, the speciation and size-specific distribution of particle-bound mercury in filterable particulate matter (FPM) from an ultra-low emission power plant and condensable particulate matter (CPM) from an entrained flow reactor were analyzed. Most importantly, particle-bound mercury was enriched in fine particles smaller than 0.02 µm, whose mass fraction was several orders of magnitude higher than that in large particles. Particularly, HgBr2, HgCl2, and HgO were major mercury species in FPM, whereas CPM involves mostly HgCl2 with a small portion of HgBr2. The occurrence of these species was also confirmed by a thermodynamic equilibrium calculation. The results further revealed the effects of air pollution control devices (APCDs) on the speciation of particle-bound mercury. Specifically, an electrostatic precipitator (ESP) removed most particle-bound mercury. Similarly, wet flue gas desulfurization (WFGD) dramatically reduced particle-bound mercury for most particles, except those between 0.1 and 1 µm. At the outlet of WFGD, mercury bound with FPM10 (smaller than 10 µm) is only 0.15% of the total mercury at the inlet of selective catalytic reduction (SCR). This knowledge provides insights that can be used to design and optimize the control strategy for mercury emission in power plants.

9.
Sci Total Environ ; 754: 142150, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-32920404

RESUMO

The purpose of this research was to improve the sorption ability of Pb and Cd by promoting the ion exchange and precipitation capacity of biochar. The adsorption performance and mechanisms of Pb and Cd in wastewater using coconut shell biochar modified with magnesium were investigated. After modification, the total adsorption capacity (Qt) of Pb and Cd on Mg-coated biochar (MgBC400) increased by 20 and 30 times compared with the unmodified biochar (BC400), respectively. The removal of Pb and Cd to biochar was attributed to ion exchange (Qe), mineral precipitation (Qp), interaction with oxygen functional groups (OFGs) [(Qf)], and metal-π electron coordination (Qπ). Compared with the BC400, the adsorption capacity of the four fractions of MgBC400 increased especially the ion exchange and precipitation. The Qe values of MgBC400 were almost 49 and 59 times that of BC400 in the adsorption of Pb and Cd, respectively. The Qp values of MgBC400 increased by 214.4 and 81.7 mg/g, respectively. Ion exchange and mineral precipitation dominated the adsorption of Pb and Cd by MgBC400.


Assuntos
Cádmio , Águas Residuárias , Adsorção , Cádmio/análise , Carvão Vegetal , Troca Iônica , Chumbo
10.
J Colloid Interface Sci ; 580: 77-87, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32682118

RESUMO

The performance of a supercapacitor (SCs) fabricated from coal-based activated carbon was studied in terms of its specific capacitance (C), life cycle and rate performance. In this work, a low cost modified nitrogen-doped coal-based activated carbon (MACN) was prepared by KOH/H2O co-activation from lignite. Experimental results and density functional theory (DFT) calculations showed that introducing nitrogen atoms into the coal-based activated carbon leads to a rearrangement of the carbon skeleton structure and changes the surface chemical environment. Leading to the MACN internal disorder increases (ID/IG is up to 0.99), structural stability improves (TGA curves shift right), and various nitrogen functional groups (N-5, N-6, N-Q) are formed on the carbon surface. In addition, the MACN possesses high specific surface area (SBET: 2129 m2/g), abundant micropores (Vmic: 0.62 cm3/g), appropriate mesopores (Vmes: 0.39 cm3/g, Vmes ratio: 38.6%), low impurity content, and highly N-doping (9.59 wt%). These characteristics of the MACN provide for a high C of 323 F/g at a current density of 0.5 A/g. The enhanced MACN is 64.8% higher than the undoped MAC. Furthermore, a high energy density of 10 Wh/kg can be achieved with a MACN-assembled symmetrical cell when the power density of 250 W/kg in 6 M KOH.

11.
Medicine (Baltimore) ; 99(1): e18536, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31895789

RESUMO

It remains challenging for endoscopists to manage pancreaticobiliary diseases in patients with ectopic papilla of Vater by endoscopic retrograde cholangiopancreatography (ERCP). The present study sought to evaluate the efficacy and safety of ERCP for this issue.Consecutive patients with ectopic papilla of Vater who underwent initial ERCP due to pancreaticobiliary diseases were retrospectively analyzed.One hundred seven patients with ectopic papilla of Vater were included. The success rate of cannulation was 83.2%. Endoscopic sphincterotomy, endoscopic papillary balloon dilation, and mechanical lithotripsy were performed in 12 (11.2%), 25 (23.4%), and 1 (0.9%) patients, respectively. The technical success rate was 83.2%; of these, endoscopic nasobiliary drainage, endoscopic retrograde biliary drainage, endoscopic retrograde pancreatic drainage, and stone extraction was conducted in 61 (57.0%), 17 (15.9%), 5 (4.7%), and 45 (42.1%) patients, respectively. Bile duct stone size ≥1 cm, number ≥2, and duodenum stenosis were risk factors for stone extraction inability. Adverse events occurred in 20 (18.7%) patients, including post-ERCP pancreatitis (3.7%), hyperamylasemia (12.1%), and infection of biliary tract (2.8%); all of the adverse events were mild and alleviated by conventional therapies.ERCP is an appropriate choice for pancreaticobiliary diseases in patients with ectopic papilla of Vater due to its high efficacy and safety. Bile duct stone size ≥1 cm, number ≥2, and duodenum stenosis increase difficulties for stone extraction.


Assuntos
Ampola Hepatopancreática , Doenças Biliares/cirurgia , Colangiopancreatografia Retrógrada Endoscópica/métodos , Coristoma/cirurgia , Duodenopatias/cirurgia , Pancreatopatias/cirurgia , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento
12.
J Hazard Mater ; 381: 120986, 2020 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-31430639

RESUMO

A series of Mn-Ce/SAPO-34 catalysts were prepared to study the catalytic oxidisation of elemental mercury (Hg0). Sulphur tolerance and SO3 formation over the catalyst were studied further. Hg0 was transported by compressed air from PSA Cavkit. NO, SO2, and NH3 are standard gases, and H2O is produced by gas carrying. Mn could incorporate into the cerium oxide lattice to form capping oxygen and well-dispersed high valance manganese ions after the addition of Ce, which was conducive to NO removal and Hg0 oxidisation. 9 Mn-9Ce showed the best performance regarding Hg0 conversion, achieving more than 92% Hg0 conversion efficiency at 50-300 °C. The sulphur resistance of the Mn-based catalyst was significantly improved after the addition of cerium due to the high affinity of Ce for SO2, and the relative content of HgSO4 was exceeded 72% on the 9 Mn-9Ce catalyst with SO2; SO3 formation over the 9 Mn-9Ce decreased by 17% compared with the 9 Mn. H2O not only reduced the available active site, but also decreased the oxidation rate of SO2. The active sites were preferentially occupied by NH3 rather than Hg0 and SO2, generated NH4+ occupied cation vacancies. Therefore, both H2O and NH3 have inhibitory effects on Hg0 conversion and SO3 formation.

13.
Bioresour Technol ; 297: 122388, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31734064

RESUMO

After the co-combustion of tobacco stem/black bean straw/wheat straw/millet straw/corn stalk/rice straw and coal, it was found that all tested biomass in this study could inhibit arsenic release, but only rice straw promoted arsenic release. When the acid washed biomass was mixed with coal during combustion, the release of arsenic increased. When mineral metals (Na, K, Mg, Ca, Al and Fe) and Si elements were added to the coal, the mineral metals inhibited arsenic release. However, the release of arsenic was increased when the silicon content in biomass was high. The volatiles in the biomass also promoted the release of arsenic during co-combustion. The arsenic in the ash generated from co-combustion was mainly in the sulphide-bound state. Co-combustion of biomass and coal reduced the occurrence of an exchangeable state in the ash, and also significantly reduce the possibility of leaching.


Assuntos
Arsênio , Carvão Mineral , Biomassa , Cinza de Carvão , Minerais
14.
Bioresour Technol ; 291: 121859, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31362200

RESUMO

The adsorption mechanisms of Pb(II) and Cd(II) in aqueous solution using camellia seed husk biochars pyrolyzed at different temperatures were studied. The adsorption of Pb(II) and Cd(II) on biochars are mainly controlled by ion exchange, oxygen functional groups (OFGs) complexation, Pb(II)/Cd(II)-π interactions, and precipitation with minerals. Compared to the raw biochars, both carboxyl and phenolic hydroxyl groups increased in the biochars washed with HCl. However, the previous research ignored the effect of the increased OFGs. Thus, a revised method was proposed from this study to more accurately calculate the contribution of four different mechanisms. Precipitation with minerals was the dominant mechanism for Pb(II) and Cd(II) removal, accounting for 80.61-89.03% and 53.57-75.84%, respectively, of the total adsorption as the pyrolysis temperature increased from 300 °C to 700 °C. As for oxygen functional groups complexation, the percentage of Pb(II) and Cd(II) removal were 4.76-8.55% and 11.34-29.59%, respectively.


Assuntos
Cádmio/química , Carvão Vegetal/química , Ácido Clorídrico/química , Chumbo/química , Oxigênio/química , Adsorção , Temperatura Alta , Oxirredução , Pirólise
15.
Environ Sci Technol ; 53(13): 7913-7920, 2019 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-31188572

RESUMO

Coal-fired power plants represent the largest source of mercury emissions worldwide. Using fly ash, a byproduct of these plants, as a sorbent to remove mercury has proven to be difficult. Here, we found that the fresh surface of modified fly ash has good adsorption performance, and it declines obviously with time because of unsaturation characteristics on surface. On the basis of this mechanism, our study provides a method to in situ capture mercury with high surface energy modified fly ash by mechanochemical and bromide treatment. Fresh modified fly ash with active sites is injected into the flue to directly adsorb mercury. A continuous system within a full-scale 300 MWe plant showed that the mercury adsorption performance of the modified fly ash is similar to that of activated carbon, which is the industry benchmark for the treatment of mercury emission in fossil power generation units. This is a breakthrough and indicates that modified fly ash can become an efficient and convenient industrial sorbent for the removal of mercury.


Assuntos
Poluentes Atmosféricos , Mercúrio , Adsorção , Carvão Mineral , Cinza de Carvão , Centrais Elétricas
16.
J Environ Manage ; 161: 57-62, 2015 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-26150373

RESUMO

The contamination of agricultural ground with estrogen compounds through application of animal wastes is a present concern. At the same time, current uses for waste fly ash having high carbon content are limited. To help mitigate these problems, we examine using waste fly ash as a useful adsorbent for Estradiol in pig waste digests. In this study, Estradiol was added to vials containing water and fly ash from several different power plants. After an extraction process, the amount of Estradiol in the water was measured. Commercial activated carbon was also used for comparison purposes. Vials containing varying concentrations of Estradiol and no trapping material were used as a control. The results from this study indicate that fly ash can be used as a trapping material for Estradiol in water, but that commercially available activated carbon can trap about an order of magnitude more Estradiol than the fly ash and that the effects of the fly ash matrix can both inhibit and promote the solvation of Estradiol into water depending possibly upon pH and cation concentration effects. In addition, preliminary extraction studies using pig waste digest indicate that fly ash can be used as adsorbent for Estradiol present in pig waste.


Assuntos
Fracionamento Químico/métodos , Cinza de Carvão/química , Estradiol/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Animais , Carbono/química , Estradiol/química , Concentração de Íons de Hidrogênio , Esterco , Centrais Elétricas , Suínos , Poluentes Químicos da Água/química
17.
J Environ Sci (China) ; 33: 156-62, 2015 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-26141888

RESUMO

In this study, the mercury adsorption characteristics of HBr-modified fly ash in an entrained-flow reactor were investigated through thermal decomposition methods. The results show that the mercury adsorption performance of the HBr-modified fly ash was enhanced significantly. The mercury species adsorbed by unmodified fly ash were HgCl2, HgS and HgO. The mercury adsorbed by HBr-modified fly ash, in the entrained-flow reactor, existed in two forms, HgBr2 and HgO, and the HBr was the dominant factor promoting oxidation of elemental mercury in the entrained-flow reactor. In the current study, the concentration of HgBr2 and HgO in ash from the fine ash vessel was 4.6 times greater than for ash from the coarse ash vessel. The fine ash had better mercury adsorption performance than coarse ash, which is most likely due to the higher specific surface area and longer residence time.


Assuntos
Poluentes Atmosféricos/química , Cinza de Carvão/química , Ácido Bromídrico/química , Compostos de Mercúrio/química , Adsorção
18.
Bioresour Technol ; 131: 325-32, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23370215

RESUMO

Despite much research on co-combustion of tobacco stem and high-sulfur coal, their blending optimization has not been effectively found. This study investigated the combustion profiles of tobacco stem, high-sulfur bituminous coal and their blends by thermogravimetric analysis. Ignition and burnout performances, heat release performances, and gaseous pollutant emissions were also studied by thermogravimetric and mass spectrometry analyses. The results indicated that combustion of tobacco stem was more complicated than that of high-sulfur bituminous coal, mainly shown as fixed carbon in it was divided into two portions with one early burning and the other delay burning. Ignition and burnout performances, heat release performances, and gaseous pollutant emissions of the blends present variable trends with the increase of tobacco stem content. Taking into account the above three factors, a blending ratio of 0­20% tobacco stem content is conservatively proposed as optimum amount for blending.


Assuntos
Carvão Mineral/análise , Conservação de Recursos Energéticos/métodos , Incineração , Nicotiana/química , Componentes Aéreos da Planta/química , Eliminação de Resíduos/métodos , Enxofre/química , Espectrometria de Massas , Termogravimetria
19.
J Environ Sci (China) ; 25(9): 1858-64, 2013 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-24520729

RESUMO

The mercury flux in soils was investigated, which were amended by gypsums from flue gas desulphurization (FGD) units of coal-fired power plants. Studies have been carried out in confined greenhouses using FGD gypsum treated soils. Major research focus is uptakes of mercury by plants, and emission of mercury into the atmosphere under varying application rates of FGD gypsum, simulating rainfall irrigations, soils, and plants types. Higher FGD gypsum application rates generally led to higher mercury concentrations in the soils, the increased mercury emissions into the atmosphere, and the increased mercury contents in plants (especially in roots and leaves). Soil properties and plant species can play important roles in mercury transports. Some plants, such as tall fescue, were able to prevent mercury from atmospheric emission and infiltration in the soil. Mercury concentration in the stem of plants was found to be increased and then leveled off upon increasing FGD gypsum application. However, mercury in roots and leaves was generally increased upon increasing FGD gypsum application rates. Some mercury was likely absorbed by leaves of plants from emitted mercury in the atmosphere.


Assuntos
Sulfato de Cálcio , Carvão Mineral , Gases/química , Mercúrio/química , Centrais Elétricas , Poluentes do Solo/química , Enxofre/química , Plantas/química , Água
20.
J Air Waste Manag Assoc ; 62(2): 139-50, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22442930

RESUMO

A pilot-scale field study was carried out to investigate the distribution of Hg and other selected elements (i.e., As, B, and Se), i.e., emission to ambient air, uptake by surface vegetation, and/or rainfall infiltration, after flue gas desulfurization (FGD) material is applied to soil. Three FGD materials collected from two power plants were used. Our results show Hg released into the air and uptake in grass from all FGD material-treated soils were all higher (P < 0.1) than the amounts observed from untreated soil. Hg in the soil amended with the FGD material collected from a natural oxidation wet scrubber (i.e., SNO) was more readily released to air compared to the other two FGD materials collected from the synthetic gypsum dewatering vacuum belt (i.e., AFO-gypsum) and the waste water treatment plant (i.e., AFO-CPS) of a forced oxidation FGD system. No Hg was detected in the leachates collected during the only 3-hour, 1-inch rainfall event that occurred throughout the 4-week testing period. For every kilogram of FGD material applied to soil, AFO-CPS released the highest amount of Hg, B, and Se, followed by SNO, and AFO gypsum. Based on the same energy production rate, the land application of SNO FGD material from Plant S released higher amounts of Hg and B into ambient air and/or grass than the amounts released when AFO-gypsum from Plant A was used. Using FGD material with lower concentration levels of Hg and other elements of concern does not necessary post a lower environmental risk. In addition, this study demonstrates that considering only the amounts of trace elements uptake in surface vegetation may under estimate the overall release of the trace elements from FGD material-amended soils. It also shows, under the same soil amendment conditions, the mobility of trace elements varies when FGD materials produced from different processes are used.


Assuntos
Poluentes Atmosféricos/análise , Resíduos Industriais/análise , Mercúrio/análise , Poaceae/metabolismo , Solo/análise , Ar/análise , Fertilizantes , Mercúrio/metabolismo , Projetos Piloto , Centrais Elétricas , Oligoelementos/metabolismo
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