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1.
J Colloid Interface Sci ; 605: 129-137, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34311307

RESUMO

Lithium-sulfur (Li-S) batteries are greatly expected to be the favored alternatives in the next-generation energy-storage technologies due to their exceptional advantages. However, the shuttle effect and sluggish reaction kinetics of polysulfides largely hamper the practical success of Li-S batteries. Herein, a unique iron carbide (Fe3C) nanoparticles-embedded porous biomass-derived carbon (Fe3C-PBC) is reported as the excellent immobilizer and promoter for polysulfides regulation. Such a distinctive composite strongly couples the vast active sites of Fe3C nanoparticles and the conductive network of porous biomass-derived carbon. Therefore, Fe3C-PBC is endowed with outstanding adsorptivity and catalytic effect toward inhibiting the shuttle effect and facilitating the redox kinetics of polysulfides, demonstrated by the detailed experimental demonstrations and theoretical calculation. With these synergistic effects, the Fe3C-PBC/S electrode embraces a superb capacity retention of 82.7% at 2C over 500 cycles and an excellent areal capacity of 4.81 mAh cm-2 under the high-sulfur loading of 5.2 mg cm-2. This work will inspire the design of advanced hosts based on biomass materials for polysulfides regulation in pursuing the superior Li-S batteries.


Assuntos
Lítio , Nanopartículas , Biomassa , Carbono , Compostos Inorgânicos de Carbono , Compostos de Ferro , Porosidade , Sulfetos , Enxofre
2.
J Hazard Mater ; 421: 126745, 2022 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-34364206

RESUMO

Sulfide precipitation is an efficient method to remove Cu(II) and As(III) from strongly acidic wastewater, but the instantaneous release of H2S from traditional sulfuration reagents causes serious H2S pollution. Moreover, the obtained precipitates are mixtures of CuS and As2S3, leading to difficulties in resource recovery. In this study, a calcium sulfide-organosilicon complex (CaS-OSCS), in which CaS was coated into a matrix of {[O1.5Si(CH2)3NH]CS}n (OSCS) via the coordination bonding, was developed. OSCS, as a matrix of CaS-OSCS, can ensure the sustained and stable release of H2S under strongly acidic conditions owing to its low swelling (1.75% swelling ratio) and excellent acid resistance. The release longevity of H2S from CaS-OSCS extended from 5 min up to 50 min compared with that from CaS because the hydrophobic OSCS prevented solution diffusing to the pores of CaS-OSCS and thus slowed down the hydrolysis of CaS in pores. 99% of Cu(II)/As(III) was precipitated without H2S escape, and the dosage of sulfuration reagents was reduced by 30%. In addition, CaS-OSCS improved the selective separation of copper from wastewater, and a separation factor between Cu(II) and As(III) reached 2376. This study provides a potential approach for the elimination of H2S pollution and selective recovery of copper.


Assuntos
Sulfeto de Hidrogênio , Águas Residuárias , Compostos de Cálcio , Preparações de Ação Retardada , Sulfetos
3.
J Colloid Interface Sci ; 605: 296-310, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34329981

RESUMO

This paper presents the design of a new type of intelligent and versatile all-in-one therapeutic nanoplatform for the co-delivery of chemotherapeutic drugs and photosensitizers to facilitate multimodal antitumor treatment; the system is based on hyaluronic acid (HA)-modified manganese dioxide (MnO2)-enveloped hollow porous copper sulfide (CuS) nanoparticles (CuS@MnO2/HA NPs). In this system, a CuS inner shell allows for the co-loading of doxorubicin (DOX) and indocyanine green (ICG) and induces photothermal effects, and a biodegradable MnO2 external shell affords on-demand tumor microenvironment (TME)-triggered release and catalase- andFenton-like activities. Moreover, the HA modification endows the system with a CD44 receptor-mediated tumor-targeting property. The formulated DOX and ICG co-loaded CuS@MnO2/HA (DOX/ICG-CuS@MnO2/HA) NPs were found to exhibit excellent photothermal performance both in vitro and in vivo. In addition, DOX/ICG-CuS@MnO2/HA NPs were found to display both TME and near-infrared (NIR)-responsive controlled release properties. The NPs also have a superior reactive oxygen species (ROS) generation capacity due to the combination of enhanced ICG-induced singlet oxygen and CuS@MnO2-mediated hydroxyl radicals. The cellular uptake, fluorescence imaging property, cytotoxicity, and thermal imaging of these NPs were also evaluated. In tumor-bearing mice, the DOX/ICG-CuS@MnO2/HA NPs displayeda superior antitumor efficacy (2.57-fold) as compared with free DOX. Therefore, the developed DOX/ICG-CuS@MnO2/HA NPs have a great potential for use as an all-in-one nanotherapeutic agent for the efficient and precise induction of chemo/photothermal/photodynamic/chemodynamic therapy with superior antitumor efficacy and fewer side effects.


Assuntos
Nanopartículas , Preparações Farmacêuticas , Animais , Cobre , Doxorrubicina/farmacologia , Ácido Hialurônico , Compostos de Manganês , Camundongos , Óxidos , Fármacos Fotossensibilizantes , Fototerapia , Sulfetos
4.
Spectrochim Acta A Mol Biomol Spectrosc ; 264: 120253, 2022 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-34391992

RESUMO

Globally, the environmental pollution is one of the major issues causing toxicity towards human and aquatic life. We have developed a facile and innovative sensing approach for detection of sulphide ions (S2-) present in the aqueous media using Ag0 decorated Cr2S3 NPs embedded on PVP matrix (Ag/Cr2S3-PVP). Based on the SPR phenomena, the detection of S2- ions was established. The nanohybrid was characterized using various techniques such as UV-vis spectrophotometer, High-Resolution Transmission Electron Microscopy (HR-TEM), Thermal Gravimetric Analysis (TGA), X-ray diffraction analysis(XRD), Energy-dispersive X-ray spectroscopy (EDS), Fourier-transform infrared spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The yellowish colour of Ag/Cr2S3-PVP nanohybrid turned to brown colour in presence of S2- ions. The selectivity and sensitivity of the prepared probe was studied against the other interfering metal ions. In addition, the effect of different concentration of S2- ions in the nanohybrid solution was investigated and the Limit of detection (LOD) was found to be 6.6 nM. The good linearity was found over the range of 10 nM to 100 µM with R2 value of 0.981. The paper strip based probe was developed for rapid onsite monitoring of S2- ions. The proposed method is found to be cost-effective, rapid, and simple. We have validated the practical applicability of the prepared probe for determining the concentration of S2- ions in real water samples.


Assuntos
Colorimetria , Nanopartículas Metálicas , Humanos , Limite de Detecção , Espectroscopia de Infravermelho com Transformada de Fourier , Sulfetos , Água
5.
J Environ Manage ; 301: 113828, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34583283

RESUMO

The application of CPB (Cemented Paste Backfill) can realize the clean, efficient, and safe mining of underground metal mines. Clear understanding on the triaxial mechanical properties of CPB is important to the CPB design and the stability analysis of the backfilled CPB structure. The triaxial mechanical properties of CPB can be significantly affected by the different curing conditions. In this research, triaxial compression tests of the CPB samples were carried out using the GCTS (Geotechnical Consulting & Testing System), and the considered curing conditions include different curing time (1, 3, 7 and 28 days), drainage conditions (drained and undrained) and curing temperatures (20 °C, 35 °C and 45 °C). The measured mechanical parameters were compared and analyzed against the framework of the Mohr-Coulomb criterion. Then, the vertical stress distribution of the backfilled CPB structure was calculated and discussed using the measured mechanical parameters. The results show that with the increase of the lateral constraint ratio (σc/Sd0), the elastoplastic stage of the measured deviator stress versus axial strain curve of CPB sample is gradually obvious. The peak deviator stress (Sdp) and the ultimate axial strain (εu) show the linear and negative exponential increase with the σc/Sd0 respectively. The number of cracks on the fractured surface of the CPB samples gradually decreased with the increase of σc/Sd0. The failure types of CPB samples were changed from tensile failure (σc/Sd0 = 0%) to the mixed tensile-shear failure (σc/Sd0≈10%) and compression-shear failure (σc/Sd0≥20%). Moreover, with the increase of curing time and curing temperature or under the drained curing condition, the peak deviator stress and cohesion (cb) of CPB can be significantly increased, but the corresponding internal friction angle (ϕb) is decreased. The shear mechanical parameters of CPB can significantly affect the vertical stress distribution inside the CPB structure. Therefore, when estimating the vertical stress distribution inside the backfilled CPB structure in engineering practices, it is necessary to focus on the changes of CPB shear parameters (cb and ϕb) caused by different curing conditions.


Assuntos
Materiais de Construção , Sulfetos , Mineração , Temperatura
6.
Food Chem ; 367: 130754, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34384983

RESUMO

N-acetylneuraminic acid (Neu5Ac) is widely spread in many biologically significant glycans of mammals, commonly as a terminal α-glycoside. It is of great significance to develop analytical techniques for detection of Neu5Ac. Herein, a high-sensitive fluorescent biosensor for Neu5Ac has been developed based on FRET between CdSe/ZnS quantum dots (QDs) and BHQ2, as well as exonuclease III (Exo III)-assisted recycling amplification strategy. Employing the specially designed three-level FRET systems and fluorescent signal recovery mechanism, together with five-step recycling signal amplification chain reactions, an ultralow detection limit of 24 fM was achieved. Meanwhile, good linear response ranges within 0.2-12.5 pM and 12.5-1000 pM were founded. The assay has excellent performance in real sample detection, and thus offers great potential for detection of sialic acids modified glycans/lipids in the fields of medical diagnosis and food testing.


Assuntos
Compostos de Cádmio , Pontos Quânticos , Compostos de Selênio , Animais , DNA , Exodesoxirribonucleases , Transferência Ressonante de Energia de Fluorescência , Limite de Detecção , Ácidos Siálicos , Sulfetos , Compostos de Zinco
7.
Food Chem ; 367: 130741, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34399272

RESUMO

Volatile sulfur-containing compounds (VSCs) provide an important contribution to foods due to their special odors. In this study, VSCs in 21 cold-pressed rapeseed oils (CROs) from 9 regions in China were extracted and separated by headspace solid-phase microextraction combined with gas chromatography coupled with sulfur chemiluminescence detection. 19 VSCs were identified by authentic standards, and the total concentration of VSCs in all CROs ranged from 49.0 to 18129 µg/kg. Dimethyl sulfide (DMS), with its high odor activity value (7-14574), was the most significant aroma contributor to the CROs. Furthermore, S-methylmethionine (SMM) in rapeseed was first affirmed by ultra-performance liquid chromatography-tandem mass spectrometry and isotope quantitation. The positive correlation coefficient between DMS and SMM was 0.793 (p < 0.05), which confirmed SMM as a crucial precursor of DMS in CROs. This study provided a theoretical basis for selecting rapeseed materials by the distribution of essential VSCs and the source of DMS.


Assuntos
Compostos de Enxofre , Compostos Orgânicos Voláteis , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Cromatografia Gasosa-Espectrometria de Massas , Odorantes/análise , Óleo de Brassica napus , Sulfetos , Enxofre , Compostos de Enxofre/análise , Espectrometria de Massas em Tandem , Compostos Orgânicos Voláteis/análise
8.
Sci Total Environ ; 803: 150002, 2022 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-34482143

RESUMO

Dimethyl sulfide (DMS) produced by marine algae represents the largest natural emission of sulfur to the atmosphere. The oxidation of DMS is a key process affecting new particle formation that contributes to the radiative forcing of the Earth. In this study, atmospheric DMS and its major oxidation products (methanesulfonic acid, MSA; non-sea-salt sulfate, nss-SO42-) and particle size distributions were measured at King Sejong station located in the Antarctic Peninsula during the austral spring-summer period in 2018-2020. The observatory was surrounded by open ocean and first-year and multi-year sea ice. Importantly, oceanic emissions and atmospheric oxidation of DMS showed distinct differences depending on source regions. A high mixing ratio of atmospheric DMS was observed when air masses were influenced by the open ocean and first-year sea ice due to the abundance of DMS producers such as pelagic phaeocystis and ice algae. However, the concentrations of MSA and nss-SO42- were distinctively increased for air masses originating from first-year sea ice as compared to those originating from the open ocean and multi-year sea ice, suggesting additional influences from the source regions of atmospheric oxidants. Heterogeneous chemical processes that actively occur over first-year sea ice tend to accelerate the release of bromine monoxide (BrO), which is the most efficient DMS oxidant in Antarctica. Model-estimates for surface BrO confirmed that high BrO mixing ratios were closely associated with first-year sea ice, thus enhancing DMS oxidation. Consequently, the concentration of newly formed particles originated from first-year sea ice, which was a strong source area for both DMS and BrO was greater than from open ocean (high DMS but low BrO). These results indicate that first-year sea ice plays an important yet overlooked role in DMS-induced new particle formation in polar environments, where warming-induced sea ice changes are pronounced.


Assuntos
Camada de Gelo , Água do Mar , Regiões Antárticas , Sulfetos/análise
9.
J Colloid Interface Sci ; 606(Pt 1): 261-271, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34390993

RESUMO

Morphological and structural characteristics of semiconductors have a significant impact on their gas sensing characteristics. Reasonable design and synthesis of heterojunctions with special structures can effectively improve sensor performance. Herein, a cobalt oxide (Co3O4) nanofibers/cadmium sulfide (CdS) nanospheres hybrid was synthesized by an electrospinning method combined with a hydrothermal method to detect acetone gas. By adjusting loading amount of CdS, the sensing performance of CdS/Co3O4 sensor for acetone at room temperature (25 °C) was greatly ameliorated. In particular, the response of CdS/Co3O4 to 50 ppm acetone gas increased by 25% under 520 nm green light, meanwhile, the response/recovery time was shortened to 5 s/4 s. This is attributed to the heterojunction formed between CdS and Co3O4 as well as the influence of light excitation on the carrier concentration of the surfaces. Meanwhile, the unique high-porosity fiber structure and the catalytic action of cobalt ions also play an essential role in improving the performance. Furthermore, practical diabetic breath was experimentally simulated and proved the potential of the sensor in the future application of disease-assisted diagnosis.


Assuntos
Diabetes Mellitus , Nanofibras , Nanosferas , Acetona , Biomarcadores , Compostos de Cádmio , Humanos , Sulfetos
10.
J Colloid Interface Sci ; 606(Pt 1): 688-695, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34416458

RESUMO

Herein, we systematically investigated the mechanisms of OH production and arsenic (As(III)) oxidation induced by sulfur vacancy greigite (Fe3S4) under anoxic and oxic conditions. Reactive oxygen species analyses revealed that sulfur vacancy-rich Fe3S4 (SV-rich Fe3S4) activated molecular oxygen to produce hydrogen peroxide (H2O2) via a two-electron reduction pathway under oxic conditions. Subsequently, H2O2 was decomposed to OH via the Fenton reaction. Additionally, H2O was directly oxidized to OH by surface high-valent iron (Fe(IV)) resulting from the abundance of sulfur vacancies in Fe3S4 under anoxic/oxic conditions. These differential OH-generating mechanisms of Fe3S4 resulted in higher OH production of SV-rich Fe3S4 compared to sulfur vacancy-poor Fe3S4 (SV-poor Fe3S4). Moreover, the OH production rate of SV-rich Fe3S4 under oxic conditions (19.3 ± 1.0 µM•h-1) was 1.6 times greater than under anoxic conditions (11.8 ± 0.4 µM•h-1). As(III) removal experiments and X-ray photoelectron spectra (XPS) showed that both OH production pathways were favorable for As(III) oxidation, and a higher concentration of As(V) was immobilized on the surface of SV-rich Fe3S4 under oxic conditions. This study provides new insights concerning OH production and environmental pollutants removal mechanisms on surface defects of Fe3S4 under anoxic and oxic conditions.


Assuntos
Arsênio , Peróxido de Hidrogênio , Radical Hidroxila , Ferro , Oxirredução , Sulfetos , Enxofre
11.
Chemosphere ; 286(Pt 1): 131672, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34346328

RESUMO

The glass system SiO2-B2O3-Na2O3-ZnO containing 2 wt% CdS and 1 wt% ZnS was synthesized by the conventional melt quench method. Glass transition temperature and crystallization temperature was determined from Differential thermal analysis (DTA) measurement to optimize heat-treatment. The amorphous structure of the glass was confirmed by the X-ray diffraction (XRD) measurement. Glasses were heat-treated by optimized heat-treatment schedule to grow CdS/ZnS QDs and crystalline phases of CdS and ZnS were confirmed by the XRD measurement. High-Resolution Transmission Electron Microscopy (HRTEM) was used to determine the size and shape of quantum dots (QDs) grown in the glass matrix. The optical band gap was calculated from the absorption spectra and found to decrease with increase in size of QDs. Electron-hole recombination rate was studied using a decay time and impedance analyzer. Prepared samples were tested as a photocatalyst under sunlight for the degradation of indigo carmine (IC) dye and photodegradation efficiency was found to be 73.6 % and 87.2 % for samples CZ1 and CZ4 respectively. No significant change is observed in degradation efficiency even for 4 cycles which confirms the stability of prepared glasses for dye degradation.


Assuntos
Pontos Quânticos , Carmim , Índigo Carmim , Dióxido de Silício , Sulfetos , Compostos de Zinco
12.
Chemosphere ; 286(Pt 3): 131876, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34418657

RESUMO

Herein, sulfide-modified nanoscale zero-valent iron (S-nZVI) was prepared by a liquid-phase reduction route and then applied to activate persulfate (PS) for the degradation of chloramphenicol (CAP). The effects of Fe/S molar ratio, catalyst dosage, PS concentration, initial pH, and co-existing ions (Cl-, SO42-, CO32-) on the catalytic performance of S-nZVI/PS system were investigated. Simultaneously, the fluctuations of solution pH, oxidation-reduction potential, dissolved oxygen, and Fe2+ concentration were also monitored during the reaction. Results shown that 98.8 % of CAP could be removed under the optimum reaction conditions (S-nZVI dosage = 0.1 g/L, PS concentration = 3 mM, initial pH = 6.86). Compared to the pristine nZVI, the sulfidation behavior could critically improve the removal efficiency of CAP, ascribe to the enhancements of hydrophobicity of nZVI, production of hydroxyl radicals, and salt resistance. Furthermore, possible degradation pathways of CAP in S-nZVI/PS system were inferred based on liquid chromatography-mass spectrometry (LC-MS) and density functional theory (DFT) calculations. This study proves that the S-nZVI is a more promising catalyst for activating PS than nZVI, especially in the field of saline pharmaceutical wastewater treatment.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Cloranfenicol , Ferro , Sulfetos , Poluentes Químicos da Água/análise
13.
J Colloid Interface Sci ; 607(Pt 1): 412-422, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34509115

RESUMO

CdS/ZnO nano heterojunction was synthesized and applied in piezocatalytic degradation of rhodamine B (RhB) under ultrasonic vibration. The optimal CdS/ZnO composite with a CdS content of 35% presented the highest RhB degradation efficiency (98.8%) in 90 min. The degradation rate reached 4.02 h-1, which was 5.6 and 2.8 times higher than that of CdS and ZnO, respectively. In addition, CdS/ZnO showed high stability in the piezocatalytic reaction. The as-prepared CdS/ZnO piezocatalysts were characterized by multiple techniques to reveal the nature behind the enhanced catalytic activity. Results indicated that CdS nanoparticles were tightly loaded onto the surface of ZnO. The piezoelectric properties of the CdS/ZnO composites were the origin of their piezocatalytic behavior. The suitable band potentials of CdS and ZnO triggered the formation of a heterojunction structure, thereby driving the second distribution of the piezo-induced charge carriers. Therefore, the separation efficiency of charge carriers and the piezocatalytic performance was greatly elevated. The high piezocatalytic activity and stability indicated that CdS/ZnO may have wide application potential in the piezocatalytic degradation of organic dyes by using ultrasonic vibration energy.


Assuntos
Compostos de Cádmio , Óxido de Zinco , Sulfetos , Ultrassom , Águas Residuárias
14.
Sci Total Environ ; 803: 150064, 2022 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-34525700

RESUMO

Chloroacetamides are commonly used in herbicide formulations, and their occurrence has been reported in soils and groundwater. However, how their chemical structures affect transformation kinetics and pathways in the presence of environmental reagents such as hydrogen sulfide species and black carbon has not been investigated. In this work, we assessed the impact of increasing Cl substituents on reaction kinetics and pathways of six chloroacetamides. The contribution of individual pathways (reductive dechlorination vs. nucleophilic substitution) to the overall decay of selected chloroacetamides was differentiated using various experimental setups; both the transformation rates and product distributions were characterized. Our results suggest that the number of Cl substituents affected reaction pathways and kinetics: trichloroacetamides predominantly underwent reductive dechlorination whereas mono- and dichloroacetamides transformed via nucleophilic substitution. Furthermore, we synthesized eight dichloroacetamide analogs (Cl2CHC(=O)NRR') with differing R groups and characterized their transformation kinetics. Dynamic NMR spectroscopy was employed to quantify the rotational energy barriers of dichloroacetamides. Our results suggest that adsorption of dichloroacetamides on black carbon constrained R groups from approaching the dichloromethyl carbon and subsequently favored nucleophilic attack. This study provides new insights to better predict the fate of chloroacetamides in subsurface environments by linking their structural characteristics to transformation kinetics and pathways.


Assuntos
Carbono , Sulfetos , Acetamidas , Cinética , Espectroscopia de Ressonância Magnética , Oxirredução
15.
J Colloid Interface Sci ; 607(Pt 2): 1825-1835, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34688975

RESUMO

Metal chalcogenides have been intensively investigated as antibacterial agents due to their unique structures and superior photoactivities. Herein, various structures of copper sulfide (CuS), a metal chalcogenide, such as microspheres (MSs), nanosheets (NSs), and nanoparticles (NPs), were developed in this work for antibacterial applications. A hydrothermal process was utilized to synthesize CuS MSs, CuS NSs, and CuS NPs. Under simulated solar light and near-infrared (NIR) light irradiation, the antibacterial behaviors, reactive oxygen species (ROS) production, and light-driven antibacterial mechanisms of CuS MSs, CuS NSs, and CuS NPs were demonstrated with the bacterium Escherichia coli (E. coli). Bacterial growth curves and ROS generation tests indicated that CuS NSs and CuS NPs had higher light-driven antibacterial activities than that of CuS MSs. ROS of hydroxyl (·OH) and superoxide anion radicals (O2-) were investigated via an electron spin resonance (ESR) spectroscopic analysis by respectively incubating CuS MSs, CuS NSs, and CuS NPs with E. coli under simulated solar light irradiation. Furthermore, E. coli incubated with CuS NPs and CuS NSs showed substantial bacterial degradation after NIR laser irradiation, which was attributed to their photothermal killing effects. Light-driven antibacterial mechanisms of CuS NSs and CuS NPs were investigated, and we discovered that under simulated solar and NIR light irradiation, CuS NSs and CuS NPs produced photoinduced electrons, and the copper ions and photoinduced electrons then reacted with atmospheric moisture to produce hydroxide and superoxide anion radicals and heat, resulting in bacterial mortality.


Assuntos
Cobre , Nanopartículas , Antibacterianos/farmacologia , Cobre/farmacologia , Escherichia coli , Sulfetos
16.
J Colloid Interface Sci ; 607(Pt 2): 942-953, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34571315

RESUMO

A hollow core-shell potassium phosphomolybdate (KMoP)@cadmium sulfide (CdS)@bismuth sulfide (Bi2S3) Z-scheme tandem heterojunction is fabricated by a simple hydrothermal strategy and kept in a water bath to continue the reaction. At the same time, the ternary structure combined Keggin-type polyoxometalate with two photosensitive sulfide semiconductors to form a stable hollow core-shell heterojunction. KMoP@CdS@Bi2S3 with a narrow band gap of âˆ¼ 1.2 eV also has excellent photothermal performance, which may further promote photocatalytic efficiency. The hollow core-shell KMoP@CdS@Bi2S3 tandem heterojunction shows excellent H2 production performance, CrVI reduction ability and photocatalytic degradation performance of highly toxic tetracycline (TC). Under visible light irradiation, the photocatalytic H2 generation rate of the KMoP@CdS@Bi2S3 tandem heterojunction reaches 831 µmol h-1, which is 103 times higher than that of pristine KMoP. The photocatalytic reduction efficiency of CrVI and degradation efficiency of TC are as high as 95.5 and 97.51%, ∼4 times higher than that of KMoP. The boosted photocatalytic performance can be ascribed to the formation of core-shell Z-scheme tandem heterojunctions favoring spatial charge separation and the narrow band gap, which extends the photoresponse to visible light/NIR regions. When TC and CrVI exist at the same time, the reduction efficiency of CrVI can be as high as 99.64% because the intermediate of TC degradation can promote the reduction of CrVI. In addition, the photocatalytic performance of the KMoP@CdS@Bi2S3 heterojunction remains nearly constant after 4 recycles, which indicates high stability. The design strategy may provide new insights for preparing other high-performance core-shell tandem heterojunction photocatalysts for solar energy conversion.


Assuntos
Cádmio , Potássio , Bismuto , Compostos de Cádmio , Catálise , Molibdênio , Ácidos Fosfóricos , Sulfetos
17.
Sci Total Environ ; 804: 150143, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34798727

RESUMO

Sulfide partial denitrification (SPD) is an alternative pathway for nitrite production accompanied with elemental sulfur (S0) production for nitrate removal from wastewater with anammox. In this study, the SPD granular sludge was cultivated for the first time in an upflow anaerobic sludge bed (UASB) reactor to reach the efficacy of maximum nitrate-to-nitrite transformation ratio of 92% and an in-situ maximum NO3--N reduction rate of 2.46 kg-N/m3-d, both much higher than literature results. Mature granules had an average particle size of 2.52 mm and hold smooth surface with excess rod bacteria. The elements Ca and S, and proteins in extracellular polymeric substances contributed to granule structure's stability. Enriched Thiobacillus genus was proposed to accumulate nitrite at moderate HRT (2-6 h). The immobilized functional strains assist efficient partial nitrification reactions to be realized with formed S0 as byproduct.


Assuntos
Nitritos , Águas Residuárias , Reatores Biológicos , Desnitrificação , Nitratos , Nitritos/análise , Nitrogênio , Oxirredução , Esgotos , Sulfetos , Águas Residuárias/análise
18.
Chemosphere ; 286(Pt 1): 131638, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34303908

RESUMO

Soil samples were collected from a representative arsenic (As) contaminated region under phytoremediation of hyperaccumulation plants. Relative abundance and diversity of microbial communities in the soil samples were characterized via 16S rRNA genes sequencing. At the phylum level, Proteobacteria, Actinobacteria, Acidobacteria, Bacteroidetes, Gemmatimonadetes and Firmicutes shows the highest abundance, accounting for more than 90 % of the classified sequences in the soil samples. Physicochemical parameters including pH, total organic carbon (TOC), cation exchange capacity (CEC), and electrical conductivity (EC), and heavy metal concentrations including total and bioaccessible contents in the soil samples were determined to investigate potential relationships between the microbial communities and the environmental factors. Principal component analysis (PCA) based on the operational taxonomic units (OTUs) matrix revealed distinct separation among the samples. The soil pH was confirmed as the dominant force to discriminate the soil samples with similar land use type and heavy metal contamination. There was little relevance between the total concentrations of heavy metals and the microbial communities. However, the bioaccessible concentrations of heavy metals were associated with the physicochemical parameters and relative abundances of bacterial genera according to correlation analyses. Although the soil samples were considerably contaminated by As, the abundances of bacterial phyla linked with As were lower than 1.0 % in most of the soil samples. The results indicated that the abundances of microbial communities in the soils were the consequence of concerted effects from all the environmental factors.


Assuntos
Metais Pesados , Microbiota , Poluentes do Solo , Arsenicais , Metais Pesados/análise , RNA Ribossômico 16S/genética , Solo , Microbiologia do Solo , Poluentes do Solo/análise , Sulfetos
19.
J Colloid Interface Sci ; 606(Pt 2): 1299-1310, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34492467

RESUMO

The ecosystems and human health were seriously threatened by hexavalent chromium (Cr(VI)) in wastewater. In this article, using the idea of the highly matched energy band structure between indium sulfide (In2S3) and MIL-53(Fe), a Type-II heterojunction has been constructed by loading In2S3 on MIL-53(Fe) microrod to overcome the fault like high recombination rates of photogenerated electron-holes of In2S3. The composite with 20:1 mass ratio of In2S3 to MIL-53(Fe) (IM-2) was adopted as an optimal sample for efficient photocatalytic Cr(VI) reduction under visible light. Various characterization techniques were used to verify the characteristics of composites and delved into the structure-effect relationship between this heterojunction and its activity. Results showed that the reaction rate constants of the photoreduction process over IM-2 was ~ 4 and 26 times higher than those of pure In2S3 and MIL-53(Fe), respectively, and the catalyst could maintain superior removal efficiency (88.6%) and steady crystal structure after four cycles. First-principles calculations further illustrated that the heterostructure formed between In2S3 and MIL-53(Fe) could effectively accelerate the separation of photogenerated electrons and holes, thus improving the photocatalytic reduction performance. Moreover, the active species analyses revealed that the superoxide radicals and electrons were mainly involved in the reduction of Cr(VI).


Assuntos
Ecossistema , Índio , Cromo , Humanos , Luz , Dietilamida do Ácido Lisérgico/análogos & derivados , Sulfetos
20.
Anal Sci ; 37(11): 1589-1595, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34759092

RESUMO

A conductive molten salt was synthesized by using natural pyrite (PR) and silver nanoparticles (Ag) at 450°C using a molten salt method. The molten-salt-composite (PR/Ag) was used as an electrocatalyst to detect hydrogen peroxide (H2O2). The as-prepared PR/Ag possessed higher conductivity than natural PR. It exhibited a high sensitivity of 603.54 µA mM-1 cm-2 for the detection of H2O2, with a linear range of 0.1 to 30 mM, and a detection limit of 0.02 mM (S/N = 3). In addition, the PR/Ag sensor exhibited good selectivity to H2O2, resisting interference from other potential interferent compounds (e.g. uric acid, glucose, fructose and common metal ions (K+, Mg2+, Na+)). The approach is considered to provide a sensitive, selective, and reliable tool for highly detection of H2O2.


Assuntos
Nanopartículas Metálicas , Prata , Técnicas Eletroquímicas , Peróxido de Hidrogênio , Ferro , Sulfetos
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