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1.
Nano Lett ; 24(14): 4241-4247, 2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38546270

RESUMO

Electrochemistry that empowers innovative nanoscopic analysis has long been pursued. Here, the concept of aggregation-enabled electrochemistry (AEE) in a confined nanopore is proposed and devised by reactive oxygen species (ROS)-responsive aggregation of CdS quantum dots (QDs) within a functional nanopipette. Complementary Faradaic and non-Faradaic operations of the CdS QDs aggregate could be conducted to simultaneously induce the signal-on of the photocurrents and the signal-off of the ionic signals. Such a rationale permits the cross-checking of the mutually corroborated signals and thus delivers more reliable results for single-cell ROS analysis. Combined with the rich biomatter-light interplay, the concept of AEE can be extended to other stimuli-responsive aggregations for electrochemical innovations.

2.
Phys Chem Chem Phys ; 26(12): 9601-9607, 2024 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-38465792

RESUMO

Four high-pressure N-rich compounds (Pmn21-CeN7, Amm2-CeN9, P1̄-CeN10, and P1̄-II-CeN10) are proposed using first-principles calculations. Novel polymeric units (a heart shaped layered structure, chain-like N8 rings, and two new banded structures) in four cerium nitrides are reported for the first time in this study. The analyses of electronic structures and bonding properties show that the charge transfer between Ce and N atoms promotes the formation of the Ce-N ionic bond and N-N covalent bond, which play an important role in stabilizing the nitrogen skeleton. Four new phases possess high energy densities (3.24-3.86 kJ g-1), indicating that they are favorable high-energy density materials. Moreover, P1̄-CeN10 possesses ultra-incompressibility along the [1 0 0] direction. Finally, infrared and Raman spectra are analyzed to provide guidance for experimental synthesis.

3.
Zhongguo Zhong Yao Za Zhi ; 45(17): 4211-4220, 2020 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-33164406

RESUMO

To prepare Cangyi nanoemulsion in situ gel and study its nasal mucosa release mechanism in vitro. After proper treatment of different drugs in the compound, the prescription of nanoemulsion was determined by pseudo-ternary phase diagram method. With the ratio of mixed emulsifier to oil phase [(S+COS)/O], the ratio of mixed emulsifier(K_m), the ratio of water phase to mixed emulsifier and oil phase[W/(S+COS+O)] as investigation factors and the normalized value(OD) as evaluation index, the prescription of Cangyi nanoemulsion was optimized by central composite design-response surface method. With the ratio of poloxamer 407(P407) and poloxamer 188(P188) as the investigation factors and the gelation temperature as the evaluation index, the in situ gel prescription of Cangyi nanoemulsion was optimized. The improved Franz diffusion cell was used to explore the nasal mucosa drug-release mechanism of Cangyi nanoemulsion in situ gel with oxymatrine, ferulic acid and salvianolic acid B content as indexes. The optimal prescription of Cangyi nanoemulsion in situ gel was as follows: 6.862% castor oil polyoxyl(EL), 4.262% absolute ethanol, 1.392% ethyl oleate, 7% P407 and 6% P188. The average pH was 5.55 and the average gelation temperature was 32.8 ℃. In vitro release studies showed that oxymatrine, ferulic acid and salvianolic acid B were released simultaneously and the drug release behavior was consistent with that in Higuchi model. The preparation process of Cangyi nanoemulsion in situ gel is stable, with suitable pH value, gelation temperature and viscosity. It has a certain slow-release effect, and can meet the needs of local nasal drug use.


Assuntos
Mucosa Nasal , Poloxâmero , Liberação Controlada de Fármacos , Emulsões/metabolismo , Géis , Mucosa Nasal/metabolismo , Temperatura , Viscosidade
4.
Phytopathology ; 109(6): 972-982, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30714883

RESUMO

Plant survival in the terrestrial ecosystem is influenced by both beneficial and harmful microbes. Trichoderma spp. are a group of filamentous fungi that promote plant growth and resistance to harmful microbes. Previously, we showed that the genus Trichoderma could effectively suppress Fusarium wilt in cucumber. However, the mechanisms that underlie the effects of the genus Trichoderma on plant defense have not been fully substantiated. Two essential metabolic pathways, such as the ascorbate (AsA)-glutathione (GSH) cycle and the oxidative pentose phosphate pathway (OPPP), have been shown to participate in plant tolerance to biotic stressors; nevertheless, the involvement of these pathways in Trichoderma-induced enhanced defense remains elusive. Here, we show that Trichoderma harzianum could alleviate oxidative and nitrostative stress by minimizing reactive oxygen species (ROS; hydrogen peroxide and superoxide) and reactive nitrogen species (nitric oxide [NO]) accumulation, respectively, under Fusarium oxysporum infection in cucumber roots. The genus Trichoderma enhanced antioxidant potential to counterbalance the overproduced ROS and attenuated the transcript and activity of NO synthase and nitrate reductase. The genus Trichoderma also stimulated S-nitrosylated glutathione reductase activity and reduced S-nitrosothiol and S-nitrosylated glutathione content. Furthermore, the genus Trichoderma enhanced AsA and GSH concentrations and activated their biosynthetic enzymes, γ-GCS and l-galactono-1,4-lactone dehydrogenase. Interestingly, the genus Trichoderma alleviated Fusarium-inhibited activity of glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase, enzymes involved in the OPPP. Such positive regulation of the key enzymes indicates the adequate maintenance of the AsA-GSH pathway and the OPPP, which potentially contributed to improve redox balance, energy flow, and defense response. Our study advances the current knowledge of Trichoderma-induced enhanced defense against F. oxysporum in cucumber.


Assuntos
Cucumis sativus , Fusarium , Doenças das Plantas/microbiologia , Trichoderma , Raízes de Plantas , Espécies Reativas de Oxigênio
5.
Sensors (Basel) ; 16(7)2016 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-27455275

RESUMO

A reduced grapheme oxide (rGO)/Au hybrid nanocomposite has been synthesized by hydrothermal treatment using graphite and HAuCl4 as the precursors. Characterization, including X-ray diffraction (XRD), Raman spectra, X-ray photoelecton spectroscopy (XPS) and transmission electron microscopy (TEM), indicates the formation of rGO/Au. A gas sensor fabricated with rGO/Au nanocomposite was applied for NO2 detection at 50 °C. Compared with pure rGO, rGO/Au nanocomposite exhibits higher sensitivity, a more rapid response-recovery process and excellent reproducibility.

6.
Environ Sci Technol ; 48(5): 2603-9, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24460470

RESUMO

Dissolved organic matter (DOM) in municipal wastewater was mainly characterized using high-performance liquid chromatography (HPLC) and size exclusion chromatography (HPSEC) with multi-excitation/emission fluorescence scan. Meanwhile, fluorescence excitation-emission-matrix combined with parallel factor analysis (EEM-PARAFAC) was also applied. Compared with chromatography fluorescence fingerprints, the EEM-PARAFAC model could not reflect the variety of DOM species with similar fluorescence but different physicochemical properties. The chromatography results showed that the protein-like species were variable among different municipal wastewater treatment plants, some of which are in combination with humic-like species; while there were two major humic-like species fractionated by hydrophilicity and molecular weight (MW), which are also the major contributors to UV absorbance at 254 nm. It was also identified that the relatively hydrophilic humic fractions were slightly larger than the relatively hydrophobic humic fractions. In all the investigated wastewater treatment plants, the relatively hydrophilic and larger MW humic fraction mainly contributed to the fluorescence intensity of humic-like EEM-PARAFAC components. As well as facilitating interpretations of EEM-PARAFAC components, the HPLC/HPSEC fluorescence fingerprints also contributed to a better understanding of fluorescent DOM species in municipal wastewater.


Assuntos
Cromatografia em Gel , Cromatografia Líquida de Alta Pressão , Monitoramento Ambiental/métodos , Substâncias Húmicas/análise , Espectrometria de Fluorescência , Águas Residuárias/análise , Poluentes Químicos da Água/análise , Análise Fatorial , Interações Hidrofóbicas e Hidrofílicas , Peso Molecular
7.
Heliyon ; 10(7): e29163, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38601522

RESUMO

This study delves into Ulcerative colitis (UC), a persistent gastrointestinal disorder marked by inflammation and ulcers, significantly elevating colorectal cancer risk. The emergence of single-cell RNA sequencing (scRNA-seq) technology has opened new avenues for dissecting the intricate cellular dynamics and molecular mechanisms at play in UC pathology. By analyzing scRNA-seq data from individuals with UC, our study has revealed a consistent enhancement of inflammatory response pathways throughout the course of the disease, alongside detailing the characteristics of endothelial cell damage within colitis environments. A noteworthy finding is the downregulation of Phospholysine Phosphohistidine Inorganic Pyrophosphate Phosphatase (LHPP), which exhibited a inversely correlate with STAT3 expression levels. The markedly reduced expression of LHPP in both the tissues and plasma of UC patients positions LHPP as a compelling target for therapeutic intervention. Our findings highlight the pivotal role LHPP could play in moderating inflammation, spotlighting its potential as a crucial molecular target in the quest to understand and treat UC.

8.
Appl Opt ; 52(35): 8465-70, 2013 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-24513889

RESUMO

We experimentally observed three types of pulses generated in an erbium-doped fiber laser by incorporating a homemade graphene saturable absorber (GSA). The generated pulses from the laser oscillator include dual-wavelength dark pulses, fundamentally step-like pulses, and non-soliton second-harmonic pulses. These operation regimes are first reported by using graphene as the saturable absorber. Our results will further indicate that the GSA can function well for obtaining various ultrafast pulse phenomena, highlighting the practical potential of graphene in ultrafast photonics technologies.

9.
Psych J ; 12(3): 464-466, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36916781

RESUMO

This study demonstrated that the higher stop-signal probability condition showed a longer go reaction time and shorter stop-signal reaction time (SSRT) compared with the lower stop-signal probability condition. In addition, preparation cost was correlated with SSRT. These results suggest that preparation facilitates response inhibition.


Assuntos
Inibição Psicológica , Humanos , Tempo de Reação/fisiologia
10.
Appl Opt ; 51(13): 2277-81, 2012 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-22614401

RESUMO

A single-pass backward configuration superfluorescent fiber source (SFS) based on erbium-doped photonic crystal fiber (EDPCF) with a high mean wavelength stability was proposed. The EDPCF was used to improve the intrinsic temperature dependence of the SFS. Using the optimal EDPCF length of 24.2 m and pump power of 204 mW, a 20.7 ppm mean wavelength stability of a prototype SFS was demonstrated with increased temperature from -40 °C to 60 °C. The mean wavelength had an ultra stability of 10.3 ppm with increased temperature from -20 °C to 60 °C.

11.
Appl Opt ; 51(36): 8516-20, 2012 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-23262588

RESUMO

Photonic crystal fibers (PCFs) are widely used in all-fiber, high-power lasers and supercontinuum sources. However, the splice loss between PCFs and conventional fibers limits its development. Grin fibers and coreless fibers were used as a fiber lens to achieve low-loss, high-strength splicing between PCFs and single-mode fibers (SMFs). The beam propagation method was used to optimize the lengths of grin fibers and coreless fibers for a minimum splice loss. The splice loss changing with the lengths of grin fiber, coreless fiber, and the air-hole collapsed region was systematically studied theoretically and experimentally. Ultimately, a minimum splice loss of 0.26 dB at 1064 nm was realized between a high-nonlinear PCF and a conventional SMF with this method.

12.
J Air Waste Manag Assoc ; 62(9): 1012-21, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23019815

RESUMO

UNLABELLED: Experimental studies on desulfurization and denitrification were carried out using activated carbon irradiated by microwave. The influences of the concentrations of nitric oxide (NO) and sulfur dioxide (SO2), the flue gas coexisting compositions, on adsorption properties of activated carbon and efficiencies of desulfurization and denitrification were investigated. The results show that adsorption capacity and removal efficiency of NO decrease with the increasing of SO2 concentrations in flue gas; adsorption capacity of NO increases slightly first and drops to 12.79 mg/g, and desulfurization efficiency descends with the increasing SO2 concentrations. Adsorption capacity of SO2 declines with the increasing of O2 content in flue gas, but adsorption capacity of NO increases, and removal efficiencies of NO and SO2 could be larger than 99%. Adsorption capacity of NO declines with the increase of moisture in the flue gas, but adsorption capacity of SO2 increases and removal efficiencies of NO and SO2 would be relatively stable. Adsorption capacities of both NO and SO2 decrease with the increasing of CO2 content; efficiencies of desulfurization and denitrification augment at the beginning stage, then start to fall when CO2 content exceeds 12.4%. The mechanisms of this process are also discussed. IMPLICATIONS: The prominent SO2 and NOx treatment techniques in power plants are wet flue gas desulfurization (FGD) and the catalytic decomposition method like selective catalytic reduction (SCR) or nonselective catalytic reduction (NSCR). However, these processes would have some difficulties in commercial application due to their high investment, requirement of expensive catalysts and large-scale equipment, and so on. A simple SO2 and NOx reduction utilizing decomposition by microwave energy method can be used. The pollutants control of flue gas in the power plants by the method of microwave-induced decomposition using adsorption of activated carbon/microwave desorption can meet the requirements of environmental protection, which will be stricter in the future.


Assuntos
Poluentes Atmosféricos/isolamento & purificação , Óxidos de Nitrogênio/isolamento & purificação , Dióxido de Enxofre/isolamento & purificação , Adsorção , Poluentes Atmosféricos/efeitos da radiação , Carvão Vegetal/química , Desnitrificação , Temperatura Alta , Micro-Ondas , Óxidos de Nitrogênio/efeitos da radiação , Oxigênio/química , Dióxido de Enxofre/efeitos da radiação , Água/química
13.
Br J Neurosurg ; 26(3): 340-6, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22098393

RESUMO

PURPOSE: Intracranial hemangiopericytomas (HPCs) are rare, and they have a tendency for local recurrence and metastases. The purpose of this study was to evaluate the relationship between CT perfusion (CTP) parameters and microvessel density (MVD) of HPCs and compare CTP parameters in parenchyma and peritumoral edema of HPCs. MATERIALS AND METHODS: The study was approved by the ethics committee, and written informed consent was obtained. Ten patients with HPCs and peritumoral edema, confirmed by pathological results, received 64-slice CT perfusion imaging before operation. To evaluate vascular attenuation of tumoral parenchyma, we immunostained the specimen sections for CD-34, measured the integrated optical density of all the positive stained CD-34 cells in the microscopic field, and calculated its ratio to total area of field as MVD. Perfusion analysis was calculated using the Patlak method. Using a 1-cm distance from the outer enhancing tumor margin as a boundary, the peritumoral edema was divided into an immediate and a distant part. The quantitative CTP parameters, including cerebral blood volume (CBV), permeability-surface area product (PS) of parenchyma, and immediate and distant peritumoral edemas, were compared. CBV and PS in parenchyma and immediate and distant peritumoral edemas of HPCs were also compared to their respective contralateral normal white matter. The correlations between MVD, CBV, and PS of tumoral parenchyma were analyzed. RESULTS: Positive correlations existed between CBV and MVD, PS and MVD (P < 0.05) respectively in the 10 patients. Furthermore, the values of CBV and PS in parenchyma of HPCs were significantly higher than those of the contralateral normal white matter and peritumoral edema (P < 0.05). The value of CBV in peritumoral edema of HPCs were lower than that of contralateral normal white matter (P < 0.05), while the value of PS in immediate and distant peritumoral edemas of HPCs were not significantly difference with that of contralateral normal white matter (P > 0.05). Finally, the values of CBV and PS did not show a significant difference between immediate and distant peritumoral edemas. CONCLUSIONS: CT perfusion imaging, especially determination of maximal CBV and corresponding PS values in the parenchyma, may be a useful and non-invasive technique for the preoperative evaluation of hemodynamic features of HPCs with peritumoral edema. CBV of peritumoral edema indicate that HPCs have a possibility of infiltration, this need further radiological-pathological research.


Assuntos
Edema Encefálico/diagnóstico por imagem , Neoplasias Encefálicas/irrigação sanguínea , Hemangiopericitoma/irrigação sanguínea , Microvasos/diagnóstico por imagem , Doenças Raras , Adulto , Idoso , Feminino , Hemangiopericitoma/diagnóstico por imagem , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , Doenças Raras/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos
14.
Environ Technol ; 33(13-15): 1811-7, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22988643

RESUMO

Experimental studies were carried out on flue gas denitrification using activated carbon irradiated by microwave. The effects of microwave irradiation power (reaction temperature), the flow rate of flue gas, the concentration of NO and the flue gas coexisting compositions on the adsorption property of activated carbon and denitrification efficiency were investigated. The results show that: the higher of microwave power, the higher of denitrification efficiency; denitrification efficiency would be greater than 99% and adsorption capacity of NO is relatively stable after seven times regeneration if the microwave power is more than 420 W; adsorption capacity of NO in activated carbon bed is 33.24 mg/g when the space velocity reaches 980 per hour; adsorption capacity declines with increasing of the flow rate of flue gas; the change in denitrification efficiency is not obvious with increasing oxygen content in the flue gas; and the maximum adsorption capacity of NO was observed when moisture in flue gas was about 5.88%. However, the removal efficiency of NO reduces with increasing moisture, and adsorption capacity and removal efficiency of NO reduce with increasing of SO2 concentration in the flue gas.


Assuntos
Poluentes Atmosféricos/isolamento & purificação , Carvão Vegetal , Micro-Ondas , Óxidos de Nitrogênio/isolamento & purificação , Adsorção , Poluição do Ar/prevenção & controle , Desnitrificação , Desenho de Equipamento , Gases , Dióxido de Enxofre , Água
15.
Environ Technol ; 33(10-12): 1225-30, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22856293

RESUMO

This paper describes the research background and chemistry of desulfurization and denitrification technology using microwave irradiation. Microwave-induced catalysis combined with activated carbon adsorption and reduction can reduce nitric oxide to nitrogen and sulfur dioxide to sulfur from flue gas effectively. This paper also highlights the main drawbacks of this technology and discusses future development trends. It is reported that the removal of sulfur dioxide and nitric oxide using microwave irradiation has broad prospects for development in the field of air pollution control.


Assuntos
Poluição do Ar/prevenção & controle , Desnitrificação , Micro-Ondas , Gerenciamento de Resíduos/métodos
16.
Immun Inflamm Dis ; 10(3): e574, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34953055

RESUMO

The management of acquired reactive perforating collagenosis (ARPC) is challenging. Here, we shared two cases of ARPC combined with elderly atopic dermatitis (AD) that did not respond well to conventional treatment but responded well to the monotherapy of dupilumab, which suggests that dupilumab may be an alternative option for the treatment.


Assuntos
Doenças do Colágeno , Dermatite Atópica , Dermatopatias , Idoso , Anticorpos Monoclonais Humanizados/uso terapêutico , Doenças do Colágeno/complicações , Doenças do Colágeno/tratamento farmacológico , Dermatite Atópica/complicações , Dermatite Atópica/tratamento farmacológico , Humanos
17.
Plant Cell Environ ; 34(2): 347-58, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21054437

RESUMO

Brassinosteroids (BRs) can induce plant tolerance to a variety of abiotic stresses by triggering the generation of H(2) O(2) as a signalling molecule in cucumber leaves. Whether nitric oxide (NO) also plays a signalling role and, if so, what is the relationship between NO and H(2) O(2) in BR-induced stress tolerance are unknown. Involvement of NO and H(2) O(2) in BR-induced tolerance was examined. NO accumulation and defence related gene transcripts were monitored by confocal laser-scanning microscopy and qRT-PCR, respectively. NO content was elevated after treatment with 24-epibrassinolide (EBR) and reduced with the inhibition of BR biosynthesis. EBR-induced NO production was blocked by pre-treatment with inhibitor of NADPH oxidase and a reactive oxygen species scavenger. On the other hand, EBR-induced H(2) O(2) generation was not sensitive to NO scavenger or inhibitor of NO production. Scavenging or inhibition of NO production inhibited EBR-induced tolerance to photo-oxidative and cold stress and partly blocked EBR-induced expression and activities of several antioxidant enzymes. Pre-treatment of the exogenous NO precursor, on the other hand, led to both increased stress tolerance and increased expression of antioxidant enzymes. These results strongly suggest that NO plays an important role in H(2) O(2) -dependent induction of plant stress tolerance by BR.


Assuntos
Brassinosteroides/farmacologia , Cucumis sativus/efeitos dos fármacos , Peróxido de Hidrogênio/metabolismo , Óxido Nítrico/metabolismo , Reguladores de Crescimento de Plantas/farmacologia , Adaptação Fisiológica , Cucumis sativus/enzimologia , Cucumis sativus/genética , Cucumis sativus/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Glutationa Redutase/genética , Glutationa Redutase/metabolismo , Peróxido de Hidrogênio/análise , Microscopia Confocal , Óxido Nítrico/análise , Reguladores de Crescimento de Plantas/metabolismo , Folhas de Planta/enzimologia , Folhas de Planta/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plântula/efeitos dos fármacos , Plântula/enzimologia , Plântula/genética , Plântula/metabolismo , Transdução de Sinais , Esteroides Heterocíclicos/farmacologia , Triazóis/farmacologia
18.
Mol Phylogenet Evol ; 57(2): 528-35, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20692352

RESUMO

Previous phylogenetic studies based on DNA sequence data have partially resolved taxonomic relationships among Pestalotiopsis species. There are still some morphological characters whose phylogenetic significance have not been assessed properly due to limited taxon sampling, in particular the degree of pigmentation of median cells. In this study, the stability of pigmentation of median cells of conidia in Pestalotiopsis species was evaluated in subculture, and a molecular phylogenetic analysis was conducted on 45 strains belonging to 26 species in order to reappraise the pigmentation of median cells for its significance in the taxonomy of Pestalotiopsis. Phylogenetic relationships were inferred from nucleotide sequences in ITS regions (ITS1, 5.8S and ITS2) and ß-tubulin 2 gene (tub2). The results showed that pigmentation of median cells was stable and it could be a key character in the taxonomy of Pestalotiopsis species. Instead of "concolorous" and "versicolor" proposed by Steyeart (1949), "brown to olivaceous" and "umber to fuliginous" are described and proposed in this paper.


Assuntos
DNA Fúngico/genética , Filogenia , Pigmentação/genética , Análise de Sequência de DNA , Xylariales/classificação , Xylariales/genética , Sequência de Bases , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , Homologia de Sequência de Aminoácidos
19.
J Air Waste Manag Assoc ; 70(8): 765-774, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32453680

RESUMO

Due to wet desulfurization system lacks effective control indicators for the oxidation process, so the sulfite oxidation in the slurry and the quality of gypsum become unstable. In this paper actual desulfurization system operation data are used to improve the ORP semi-empirical formula obtained in the laboratory. It was concluded that the ORP was mainly affected by the concentration of sulfite and pH during the operation of the actual desulfurization system, the dissolved oxygen was less affected by the small concentration change during operation. It is verified that the model can correct the ORP measurement value by using other conventional measurement data from the power plant. The results can provide theoretical support for adding ORP as a control index to optimize the oxidation process. IMPLICATIONS: At present, the main control parameter of wet FGD is pH control, but wet FGD has two main reactions at the same time, one is acid-base reaction, the other is redox, single pH control can not reflect the degree of redox, so it is necessary to introduce another control index to evaluate redox, which is the ORP control proposed in this paper, ORP can reflect the degree of slurry oxidation, avoid the occurrence of excessive oxidation and inadequate oxidation, so that the operation of desulfurization system can be more healthy and stable.


Assuntos
Poluição do Ar/prevenção & controle , Modelos Teóricos , Centrais Elétricas , Sulfato de Cálcio , Oxirredução , Enxofre
20.
Chemosphere ; 243: 125321, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31733541

RESUMO

In this study, size exclusion chromatography with an array of absorbance, fluorescence, organic nitrogen and organic carbon detectors was used for characterizing property and treatability of effluent organic matter (EfOM) from 12 wastewater treatment plants. According to their apparent molecular weight (AMW), EfOM fractions were assigned to biopolymers (>20 kDa), humic substances that comprise sub-fractions of humic-like acids (HA-I & HA-II, 2.3-7.0 kDa) and fulvic-like acids (FA, 1.5-2.3 kDa), building blocks (0.55-1.5 kDa) and low molecular weight neutral substances (<550 Da). The fractions of biopolymers and low molecular weight neutral substances didn't show humic-like fluorescence, while the fractions of HA-II, FA and building blocks usually had signatures of both humic-like and protein-like fluorescence. Humic substances generally contributed the largest proportion of dissolved organic carbon and nitrogen (DOC & DON) in effluents. Coagulation removed EfOM fractions following the order of biopolymers > HA subfraction > FA subfraction > building blocks, while little removal of protein-like fluorescence in HA-II and FA subfractions was detected. Anion exchange treatment could effectively reduce DOC and DON concentrations; the sequence of the treatment efficiency was humic substances > biopolymers > building blocks. Increasing O3 doses caused DOC and DON of EfOM to be gradually transformed from large AMW fractions into small AMW fractions, while chromophores and fluorophores in HA subfractions were relatively more refractory than those in the other fractions. Size exclusion chromatography with multiple detectors are suggested to be an informative technique for estimating treatability of EfOM by advanced wastewater treatment processes.


Assuntos
Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/análise , Carbono/análise , Cromatografia em Gel , Fluorescência , Substâncias Húmicas/análise , Peso Molecular , Nitrogênio/análise , Compostos Orgânicos/química , Águas Residuárias/química
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