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1.
Nanotechnology ; 35(31)2024 May 13.
Artículo en Inglés | MEDLINE | ID: mdl-38663370

RESUMEN

The overuse of antibiotics currently results in the presence of various antibiotics being detected in water bodies, which poses potential risks to human health and the environment. Therefore, it is highly significant to remove antibiotics from water. In this study, we developed novel rod-like NiCo-phyllosilicate hybrid catalysts on calcined natural zeolite (NiCo@C-zeolite) via a facile one-pot process. The presence of the zeolite served as both a silicon source and a support, maintaining a high specific surface area of the NiCo@C-zeolite. Remarkably, NiCo@C-zeolite exhibited outstanding catalytic performance in antibiotic degradation under PMS activation. Within just 5 min, the degradation rate of metronidazole (MNZ) reached 96.14%, ultimately achieving a final degradation rate of 99.28%. Furthermore, we investigated the influence of catalyst dosage, PMS dosage, MNZ concentration, initial pH value, and various inorganic anions on the degradation efficiency of MNZ. The results demonstrated that NiCo@C-zeolite displayed outstanding efficacy in degrading MNZ under diverse conditions and maintained a degradation rate of 94.86% at 60 min after three consecutive cycles of degradation. Free radical quenching experiments revealed that SO•-4played a significant role in the presence of NiCo@C-zeolite-PMS system. These findings indicate that the novel rod-like NiCo-phyllosilicate hybrid catalysts had excellent performance in antibiotic degradation.


Asunto(s)
Antibacterianos , Zeolitas , Zeolitas/química , Antibacterianos/química , Antibacterianos/síntesis química , Catálisis , Contaminantes Químicos del Agua/química , Metronidazol/química , Purificación del Agua/métodos , Silicatos/química
2.
Nanotechnology ; 32(13): 135602, 2021 Mar 26.
Artículo en Inglés | MEDLINE | ID: mdl-33285535

RESUMEN

The BiVO4/HNTs hybrid photocatalysts were synthesized by liquid phase precipitation using natural halloysite nanotubes (HNTs) as supporter and Bi(NO3)·5H2O as resource of Bi. XRD, scanning electron microscopy (SEM), transmission electron microscopy, HRTEM, x-ray photo electron spectroscopy and UV-Vis DRS were used to characterize the samples prepared at different calcination temperatures, and the effects of crystallization, Brunauer-Emmett-Teller specific surface area and morphological structure on the photoactivity were investigated. Results reveal that increasing calcination temperature can accelerate the transition of BiVO4 from tetragonal to monoclinic and also decrease the surface area of BiVO4/HNTs. The SEM results showed that BiVO4 was successfully coated on HNTs surface with ellipsoid or near rod like morphology, and the obtained BiVO4/HNTs had regular nanotube morphology. HRTEM results showed that, the regular fringe spacing of the lattice planes are about 0.474 and 0.364 nm, which is consistent with the (110) and (200) plane of the monoclinic and tetragonal BiVO4, confirming the exiting of mixed crystal structure in BiVO4/HNTs. BiVO4 with tetragonal phase (80.02%) and monoclinic phase (19.98%) mixed crystal is loaded on the surface of HNTs with calcinations at 400 °C for 2 h. The structure and Si (Al)-O bond of HNTs can be obviously changed over the calcination temperature of 400 °C. The effect of calcination temperature on photocatalytic reactivity of samples was investigated by degradation of dyes (MB, MO and RhB) under simulated solar light. And the sample calcined at 400 °C with the better mixed crystalline structure and larger specific surface area exhibits significant activity with the removal rate of MB and RhB up to 100% within 4 h. The degradation of MB follows the first order kinetic model. BiVO4/HNTs photocatalysts with the band gap of 2.34 eV has higher photocatalytic reaction rate and better sedimentation performance than Degussa P25. The photocatalytic degradation efficiency of BiVO4/HNTs for MB was no significant reduction after four times recycles.

3.
Nanotechnology ; 30(31): 315706, 2019 Aug 02.
Artículo en Inglés | MEDLINE | ID: mdl-30893671

RESUMEN

This paper reports on highly active ZnFe2O4/reduced graphene oxide (ZnFe2O4/rGO) nanocomposites synthesized by a modified sol-gel method. The as-prepared samples have been characterized by XRD, TEM, XPS and other detection methods, which demonstrate that ZnFe2O4 nanoparticles (NPs) with a diameter of 15 âˆ¼ 50 nm were densely grown on the rGO substrates. The photocatalytic activities of ZnFe2O4/rGO catalysts were evaluated by the degradation of Methylene blue (MB) under visible light. The results showed that the ZnFe2O4/rGO catalysts had high photocatalytic activity, and the degradation efficiency of MB was almost 100% within 180 min. Moreover, the ZnFe2O4/rGO catalysts also had a great removal effect on Rhodamine B (RhB) and Methyl orange (MO). Mechanistic studies revealed that the rGO acted as a stabilizer to prevent ZnFe2O4 from aggregation and improved the separation of photo-generated electrons. The high efficiency for dye degradation was attributed to the generation of hydroxyl radicals (·OH) via the photochemical decomposition of H2O2 on ZnFe2O4/rGO catalysts, which was responsible for the oxidation of the dyes. Of note, the ZnFe2O4/rGO catalyst maintained an efficiency of over 90% after five cycles. The XRD, XPS and VSM characterization revealed that the ZnFe2O4/rGO catalysts had a stable crystal structure and can be easily separated.

4.
Environ Sci Pollut Res Int ; 31(19): 28210-28224, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38532214

RESUMEN

Iron-based catalysts are environmentally friendly, and iron minerals are abundant in the earth's crust, with great potential advantages for PMS-based advanced oxidation process applications. However, homogeneous Fe2+/PMS systems suffer from side reactions and are challenging to reuse. Therefore, developing catalysts with improved stability and activity is a long-term goal for practical Fe-based catalyst applications. In this study, we prepared Fe-HNTs nanoreactors by encapsulating a nitrogen-doped carbon layer with one-dimensional halloysite nanotubes (HNTs) using the molten salt-assisted method. Subsequently, Fe (Co, Ni) nanoclusters were anchored onto the nitrogen-doped carbon layer at a relatively low temperature (550℃), resulting in stable and uniform distribution of metal nanoclusters on the surface of HNTs carriers in the form of Fe-Nx coordination. The results showed that the dissolution of the molten salt and leaching of post-treated metal oxides generated numerous mesopores within the Fe-HNTs nanoreactor, leading to a specific surface area more than 10 times that of HNTs. This enhanced mass transfer capability facilitates rapid pollutant removal while exposing more active sites. Remarkably, Fe-HNTs adsorbed up to 97% of tetracycline within 60 min. In the Fe-HNTs/PMS system, the predominant reactive oxygen species has been shown to be 1O2, and the added tetracycline was degraded by more than 98% within 5 min. The removal of tetracycline was maintained above 96% in the presence of interfering factors such as wide pH (3-11) and inorganic anions (5 mM Cl-, HCO3-, NO3-, and SO42-). The investigated mechanism suggests that efficient degradation and interference resistance of the Fe-HNTs/PMS system is attributed to the synergistic effect between the rapid adsorption of porous structure and the non-radical (1O2)-dominated degradation pathway.


Asunto(s)
Hierro , Nanotubos , Tetraciclina , Nanotubos/química , Tetraciclina/química , Catálisis , Hierro/química , Arcilla/química , Níquel/química , Oxidación-Reducción , Cobalto/química
5.
Environ Sci Pollut Res Int ; 30(32): 78750-78762, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37273048

RESUMEN

Chromium (Cr)-containing electroplating sludge is a hazardous solid waste and has a detrimental effect on human health and the environment. The existing mainstream methods still have problems such as high costs and complicated processes. In this study, the composition, phase composition, heavy metal content, microstructure, calcination characteristics, and vitrification of chromium electroplating sludge were analyzed by XRF, XRD, ICP-OES, and SEM. The results showed that calcination of sludge at 650 °C and 850 °C produces magnetic ferrite ZnFe2O4. When solidifying sludge with D245 glass, the maximum sludge addition is 35% in order to make the Cr(VI) leaching concentration meet the national standard. Here, the plastic solidification method was developed to solidify Cr-containing electroplating sludge and fill plastic building templates. This method is simple to operate, low cost, and a promising prospect. The effect of surface modification of electroplating sludge was discussed. The most obvious effect of the modification is sodium stearate, modified by sodium stearate powder oil absorption decreases value from 0.62 g/1.0 g to 0.40 g/1.0 g. When sodium stearate with 1.5% was used as the sludge surface modifier, the contact angle reached 88.98°. Then, the effect of the ratio of PVC to modification sludge on the performance of PVC building templates was investigated and compared with that of the templates prepared by calcium carbonate filling. It was found that the performance of the sludge-filled PVC template was superior to the traditional calcium-carbonate filled PVC template when the ratio of PVC to sludge is 100:150, and the tensile strength reached 15.3233 Mpa and 13.745 Mpa, respectively. Thus, this study demonstrates a new method to treat and recycle Cr-containing electroplating sludge.


Asunto(s)
Cromo , Metales Pesados , Humanos , Cromo/química , Aguas del Alcantarillado/química , Galvanoplastia , Metales Pesados/química
6.
Environ Sci Pollut Res Int ; 30(30): 75247-75261, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37213017

RESUMEN

Dissolved antibiotics have been a research subject due to their widespread presence and potential threats in drinking water treatment. To enhance the photocatalytic activity of Bi2MoO6 for the degradation of norfloxacin (NOR), the heterostructured Co3O4/Bi2MoO6 (CoBM) composites were synthesized by employing ZIF-67-derived Co3O4 on Bi2MoO6 microspheres. The as-synthesized resultant material 3-CoBM by 300 °C calcination was characterized by XRD, SEM, XPS, transient photocurrent techniques, and EIS. The photocatalytic performance was evaluated by monitoring different concentrations, NOR removal from aqueous solution. Compared with Bi2MoO6, 3-CoBM exhibited the better adsorption and elimination capacity of NOR due to the combined effect between peroxymonosulfate activation and photocatalytic reaction. The influences of catalyst dosage, PMS dosage, various interfering ions (Cl-, NO3-, HCO3-, and SO42-), pH value, and type of antibiotics for application removal were also invested. By activating PMS under visible-light irradiation, 84.95% of metronidazole (MNZ) can be degraded within 40 min, and NOR and tetracycline (TC) can be completely degraded using 3-CoBM. Degradation mechanism was elucidated by quenching tests in combination with EPR measurement, and the degree of activity of the active groups from strong to weak is h+, SO4-•, and •OH, respectively. The degradation products and conceivable degradation pathways of NOR were speculated by LC-MS. In combination of excellent peroxymonosulfate activation and highly enhanced photocatalytic performance, this newly Co3O4/Bi2MoO6 catalyst might be a promising candidate for degrading emerging antibiotic contamination in wastewater.


Asunto(s)
Norfloxacino , Peróxidos , Norfloxacino/química , Microesferas , Peróxidos/química , Antibacterianos
7.
Chemosphere ; 302: 134807, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35525443

RESUMEN

Developing efficient photocatalysts based on the peroxymonosulfate (PMS) activation for effective degradation of threatening antibiotic contamination under visible light is still a challenging subject. Herein, a Co-doped Bi2MoO6 (CBMO) spherical crystals were synthesized via a facile hydrothermal method and used to degrade artificial antibiotic wastewater via PMS activation under visible light. The obtained 3 wt% Co-doped B2MoO6 (3CBMO) can effectively remove 98.95% of norfloxacin (NOF) within 40 min, 100% of tetracycline (TC) and metronidazole (MNZ) within 30 min. Compared with the contrasting catalysts, the superior catalytic activity of 3CBMO was attributed to the synergistic effect of photocatalytic and Co(II) activated PMS degradations. Quenching tests in combination with EPR measurements revealed that the hole (h+), sulfate (SO4-•) and hydroxyl (•OH) were the primary radicals all contributed to NOF degradation. The influences of initial concentration, catalyst dosage, PMS dosage and various interfering ions (NO3-, Cl-, SO42-, and HCO3-) on the degradation efficiency of NOF were systematically examined. Furthermore, possible degradation pathways of NOF were proposed by LC-MS. This novel 3CBMO catalyst might be a promising candidate for degradation of the main sources of antibiotic contamination in pharmaceutical wastewater.


Asunto(s)
Antibacterianos , Aguas Residuales , Bismuto , Luz , Molibdeno , Norfloxacino , Peróxidos/química
8.
Environ Sci Pollut Res Int ; 29(44): 66177-66190, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35499722

RESUMEN

Phosphogypsum (PG) is one of solid wastes with large amount of yield and serious pollution, which has attracted wide attention. The aim of this study is to investigate filling performance of PG on polypropylene (PP) or high-density polyethylene (HDPE) matrix. In this work, PG was calcined initially to improve whiteness and fix impurities. X-ray diffraction (XRD) results showed that after calcined at 500 °C, the PG phase changed from CaSO4·2H2O to CaSO4. The modification effects of the three modifiers were evaluated by Fourier transform infrared spectra (FTIR), oil absorption value, water floatability, and contact angle analysis. The effects of weight fraction of PG in PP and HDPE matrix on mechanics and morphology were observed by tensile test, impact test, and scanning electron microscope. Scanning electron microscope (SEM) showed that modified PG can be dispersed uniformly in the matrix at low filling content. With the increase of PG filling content, the analysis of mechanical properties showed that the tensile strength of HDPE matrix increased, while the tensile strength of PP matrix decreased gradually. The impact strength of HDPE matrix would decrease, but the impact strength of PP matrix increased first and then decreased. Compared with calcium carbonate (CC), the mechanical properties of HDPE filled with PG performed better. The apparent density showed that polymer composites filled with PG have the characteristics of light weight.


Asunto(s)
Polietileno , Polipropilenos , Carbonato de Calcio , Sulfato de Calcio , Fósforo , Polienos , Polímeros , Residuos Sólidos , Agua
9.
Environ Sci Pollut Res Int ; 29(60): 89986-89995, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-35859233

RESUMEN

Sludge incineration is one of the most efficient sludge treatment methods. The fly ash produced by incineration must be handled further since it has a significant number of heavy metals. In this study, the chemical composition of sewage sludge incineration fly ash (SSA) generated from Zhejiang in various months was identified by XRD, X-ray fluorescence spectrometer (XRF), and SEM analyzes. The SSA were treated by a (NH4)2SO4 roasting-acid leaching process to determine its effect on the elimination performance of heavy metals. The SSA content on the mechanical properties and heavy metal leaching of modified SSA-filled PP composite were also studied. Results show (NH4)2SO4 roasting-acid leaching process has a good effect of eliminating heavy metals, with the highest leaching of Zn of 86.4%. The presence of sodium stearate modifier increases activation index of SSA and then improves the compatibility of SSA particles in PP, resulting for the composites have relatively excellent mechanical properties. For the toxicity characteristic leaching procedure (TCLP) test, modified SSA particles can be effectively encapsulated with PP resins, which have a considerable inhibitory effect on heavy metal leaching. This process from this study provides a reference for sewage sludge treatment by using modified SSA as a polymer filler to achieve the immobilization of heavy metals and the resource recycling.


Asunto(s)
Ceniza del Carbón , Metales Pesados , Aguas del Alcantarillado
10.
Artículo en Inglés | MEDLINE | ID: mdl-36269921

RESUMEN

Event extraction (EE) is a crucial research task for promptly apprehending event information from massive textual data. With the rapid development of deep learning, EE based on deep learning technology has become a research hotspot. Numerous methods, datasets, and evaluation metrics have been proposed in the literature, raising the need for a comprehensive and updated survey. This article fills the research gap by reviewing the state-of-the-art approaches, especially focusing on the general domain EE based on deep learning models. We introduce a new literature classification of current general domain EE research according to the task definition. Afterward, we summarize the paradigm and models of EE approaches, and then discuss each of them in detail. As an important aspect, we summarize the benchmarks that support tests of predictions and evaluation metrics. A comprehensive comparison among different approaches is also provided in this survey. Finally, we conclude by summarizing future research directions facing the research area.

11.
Environ Pollut ; 245: 53-62, 2019 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-30414549

RESUMEN

The N-TiO2/g-C3N4@diatomite (NTCD) composite has been prepared through a simple impregnation method, using titanium tetrachloride as precursor and urea as nitrogen-carbon source. Then the effects of calcination temperature on structure, surface property and photocatalytic activity of the catalysts were investigated. And XRD, TEM, XPS, FTIR and UV-vis diffuse adsorption spectroscopy were used to characterize the obtained powders. The photocatalytic activity of the NTCD was evaluated through the reduction of aqueous Cr (VI) under visible light irradiation (λ > 400 nm). The results demonstrated that the nano-TiO2 particles ranging from 15 to 30 nm in the crystal of anatase are well deposited on the surface of diatomite in the NTCD-500 which calcined at 500 °C for 2 h. Furthermore, the g-C3N4 with the lay thickness of 0.92 nm was attached to the surface of nano-TiO2. The N-doped TiO2 and g-C3N4 doped catalysts could co-enhance response in the visible light region and reduce band gap of NTCD-500 (Eg = 3.07 eV). And the NTCD-500 sample exhibited nearly 100% removal rate within 5 h for photocatalytic reduction of Cr (VI) which was higher activity than P25, crude TiO2@diatomite and g-C3N4@diatomite.


Asunto(s)
Calcio/química , Cromo/química , Contaminantes Ambientales/química , Restauración y Remediación Ambiental , Titanio/química , Nanopartículas Calcificantes , Carbono/química , Catálisis , Tierra de Diatomeas , Luz , Nitrógeno/química , Procesos Fotoquímicos , Temperatura , Urea/química
12.
J Hazard Mater ; 149(2): 523-6, 2007 Oct 22.
Artículo en Inglés | MEDLINE | ID: mdl-17764838

RESUMEN

Manufacturing the glass-ceramic has been proposed as a useful choice to recycle coal fly ash from power plants. In this work, a glass-ceramic of SiO2-Al2O3-Fe2O3-CaO family was synthesized by mixing 90 wt% of coal fly ash, from a power plant in west of China, with Na2O, and then melted at 1350 degrees C. The ceramization of the obtained glass was carried out at 770 degrees C for 2h. Esseneite and nepheline were found present as major crystal phases. The produced glass-ceramic exhibited good chemical durability as well as good mechanical properties. The toxicity characteristic leaching procedure (TCLP) method found that the glass-ceramic was non-hazardous.


Asunto(s)
Carbono/química , Cerámica/química , Vidrio/química , Material Particulado/química , Ceniza del Carbón , Metales Pesados/química , Microscopía Electrónica de Rastreo , Óxidos/química , Difracción de Rayos X
13.
Micron ; 71: 1-6, 2015 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-25590567

RESUMEN

Infrared spectroscopy (IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and high-resolution transmission electron microscopy (HRTEM) with energy dispersive X-ray analysis (EDS) were used to investigate the evolution of mechanical destruction of the pyrophyllite structure and final ground products upon grinding with a laboratory planetary ball mill. The raw ore used in this present work was mainly composed of pyrophyllite and quartz. This pyrophyllite was more resistant toward mechanical destruction, and the crystalline order of pyrophyllite was not completely destroyed until grinding for 240 min with a 20:1 of weight ratio of the balls to powder. The existing crystalline phase in the final ground product was found to be quartz, which served as the associated phase in the original pyrophyllite mineral. The rate of destruction of pyrophyllite structure depended on the types of chemical bonds. Additionally, increasing the intensity of grinding resulted in acceleration of the mechanically induced amorphization of the pyrophyllite structure, whereas the associated quartz grains contributed to the deceleration of the amorphization of pyrophyllite.

14.
Appl Radiat Isot ; 57(6): 813-7, 2002 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-12406621

RESUMEN

The X-ray induced color centers in soda-lime silicate glass were unstable at room temperature. There was a rapid fading at short-term stage and a slow fading at long-term stage. In the short-term stage, both first-order and second-order fading kinetics played roles in the fading process, while only the first-order fading controlled the long-term stage fading.

15.
Appl Radiat Isot ; 56(4): 621-6, 2002 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-11999161

RESUMEN

X-ray irradiation induced defects in the commercial soda-lime container glass were studied by means of optical spectrophotometer and ESR. The induced color might be applied to producing recyclable glasses. The nonbridging oxygen hole centers (NBOHCs) were mainly responsible for the irradiation induced absorptions at 431 and 627 nm of glass. The absorption at 305 nm was attributed to the trapped electron. The induced deep color can be kept for longer than 7 months, but can be almost bleached at 300 degrees C for 20 min.

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