Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 6 de 6
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
J Hazard Mater ; 373: 580-590, 2019 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-30952003

RESUMO

In this study, a new kind of thin 2D MOFs nano-sheets (MNS) was successfully prepared through complexation between 2-methylimidazole and Cu(II) by a one-step, and cost-effective route. The structural morphologies can be tuned by adjusting the ratio of MeOH/H2O. The synthesized MNS (MNS-1, MNS-2, MNS-3 and MNS-4) were fully characterized and the results indicated that the synthesized MNS were freestanding and possess micro-sized lateral dimensions and nanoscale thickness of sub-25 nm. All the obtained MNS display great performance with the adsorption capacity hierarchy of MNS-2 (591.79 mg·g-1) > MNS-3 (409.49 mg·g-1) > MNS-4 (387.07 mg·g-1) > MNS-1 (384.84 mg·g-1) at pH ˜ 6.0, and 298 K. The thermodynamic parameters indicated the exothermic and spontaneous nature of U(VI) immobilization. The U(VI) immobilization mechanism was achieved through the complexation between U(VI) and C-N(H) /-OH groups. This work supplies a facile and purposeful approach for developing 2D MOFs nano-sheets toward a highly efficient immobilization of U(VI), and it also promotes the preparation of structure-based design of nanomaterials for radionuclide-containing-medium pretreatment.

2.
Environ Pollut ; 243(Pt B): 1802-1809, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30408867

RESUMO

Although the aggregation of graphene oxide (GO) has been widely researched, the influence of the GO size on the homoaggregation behavior and its interaction with environmental media are still unexplored. In this work, critical coagulation concentration (CCC) values for GO with different sizes, from micro to nanosheet, were measured with NaCl and CaCl2 electrolytes, and the results indicated that GO with the largest size presented the smallest CCC value. Aluminum oxide (Al2O3) was selected as a natural solid particle representative to mimic the interaction between GO and environmental media. Batch experiments were conducted in solution with different pH and ionic strength. Results indicated that the attachment capacity of large GO onto Al2O3 particles was greater than that of small GO. The experimental data were well fitted with Freundlich model. The electrostatic attraction and hydrogen-bonding interaction dominated the interaction process between GO and Al2O3. These findings are important for better understanding in the environmental fate and transport of GO.


Assuntos
Grafite/química , Óxidos/química , Água/química , Óxido de Alumínio/química , Meio Ambiente , Ligação de Hidrogênio , Cloreto de Sódio/química
3.
J Colloid Interface Sci ; 513: 92-103, 2018 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-29132109

RESUMO

In this study, magnetic Fe3O4 nanoparticles (MNP) modified with O-phosphorylethanolamine (O-PEA) were successfully prepared by non-thermal plasma induced method with different treatment times. The raw and modified MNP were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectrophotometer (FT-IR), and vibration sample magnetometer (VSM). The modified MNP samples show higher adsorption capacity for U(VI) removal and longer treatment time results in higher adsorption capacity and efficiency. The experimental parameters were optimized by means of the response surface methodology to improve the removal efficiency of U(VI) by the modified adsorbents from aqueous solutions. The O-PEA modified MNP with 120 min treatment time shows the highest adsorption capacity with 228.17 mg⋅g-1 among the five samples at 293.15 K. Thermodynamic studies reveal that the adsorption process of U(VI) onto O-PEA modified MNP is endothermic and spontaneous. XPS studies indicate that the U(VI) removal is fulfilled through the binding interactions between U(VI) and NH2, OH and phosphate groups on the modified MNP surface. This work not only provides a simple, convenient and cost-effective way for water treatment by plasma modification, but also provides a new insight into preparing promising adsorbents to achieve magnetic separation from aqueous solution.

4.
R Soc Open Sci ; 4(9): 170658, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28989769

RESUMO

Atmospheric pressure nonequilibrium plasma jet has been applied to the synthesis of [60]fullerene oxides (C60On) for the first time. C60O and C60O2 were produced and isolated in high yields up to 44% and 21%, respectively. The structural assignment of C60O was confirmed by comparison with the reported spectroscopic data. Theoretical calculations of 13C NMR chemical shifts for eight isomers of C60O2 were performed and compared with the experimental data to assign the most possible structure for the obtained C60O2 dominantly as an e isomer.

5.
Sci Rep ; 7(1): 10033, 2017 08 30.
Artigo em Inglês | MEDLINE | ID: mdl-28855653

RESUMO

In this paper, biochar derived from poplar catkins was used as an economical and renewable adsorbent for adsorption organic and inorganic pollutants such as, dyes, organic compounds, and heavy metal ions from wastewater. Mesoporous activated carbonized poplar catkins (ACPCs) were produced from char as a by-product by carbonized poplar catkins (CPCs). With their high surface area, ACPCs exhibited the maximum adsorption capacities of 71.85 and 110.17 mg/g for the removal of inorganic U(VI) and Co(II). Compared other biochars adsorbents, ACPCs can also adsorb organic pollutants with the maximum adsorption capacities of 534, 154, 350, 148 and 384 mg/g for methylene blue (MB), methyl orange (MO), Congo red (CR), chloramphenicol (CAP) and naphthalene. The adsorption of organic pollutants was fitted with pseudo-first order, pseudo-second order, and intra-particle diffusion kinetic models figure out the kinetic parameters and adsorption mechanisms. Langmuir adsorption isotherm was found to be suitable for Co(II) and U(VI) adsorption and thermodynamic studies indicated adsorption processes to be endothermic and spontaneous. The adsorption process includes both outer-sphere surface complexes and hydrogen-bonding interactions. The results showed that biochar derived from poplar catkins was a potential material to remove pollutants in wastewater.

6.
J Colloid Interface Sci ; 432: 236-45, 2014 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-25086718

RESUMO

Controlled synthesis of well-shaped nanocrystals is of significant importance to understand the surface-related properties. Herein, hierarchical Bi2WO6 particles with different morphologies, such as flower-like and pancake-like morphologies were selectively prepared using a simple fluoride ion-assisted hydrothermal process. Morphological modulation of the samples could be easily realized by controlling the initial amount of NH4F. The effect of NH4F as well as the formation mechanism of these Bi2WO6 hierarchical structures were systematically investigated. The morphological control of the final products are proved to be a kinetic control of the reaction, which is closely related to the concentration of fluoride ion in the solution. The as-obtained hierarchical Bi2WO6 particles exhibit different visible-light-driven photo-catalytic activities for the degradation of Rhodamine-B (RhB). The differences in photo-catalytic activities among the as-obtained samples are associated the surface adsorption properties, which result from the synthetic conditions.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA