RESUMEN

Metallic antimony (Sb) is an attractive anode material for lithium-/sodium-ion batteries (LIBs/SIBs) because of its high theoretical capacity (660 mA h g-1), but it suffers from poor cycling performance caused by the huge volume expansion and the unstable solid electrolyte interphase (SEI). Here, we report a high-performing microsized Sb anode for both LIBs and SIBs by coupling it with fluoroethylene carbonate (FEC) containing electrolytes. The optimum amount of FEC (10 vol %) renders a stable LiF/NaF-rich SEI on Sb electrodes that can suppress the continuous electrolyte decomposition and accommodate the volume variation. The microsized Sb electrode gradually evolves into a porous integrity assembled by nanoparticles in FEC-containing electrolytes during cycling, which is totally different from that in the FEC-free counterpart. As a result, the microsized Sb electrodes exhibit a reversible capacity of 540 mA h g-1 with 85.3% capacity retention after 150 cycles at 1000 mA g-1 for LIBs and 605 mA h g-1 with 95.4% capacity retention after 150 cycles at 200 mA g-1 for SIBs. More impressively, the prototype full Li-based (i.e., Sb/LiNi0.8Co0.1Mn0.1O2 cell) and Na-based (i.e., Sb/Na3V2(PO4)2O2F cell) batteries also achieve good cycling durability. This facile strategy of electrolyte formulation to boost the cycling performance of microsized Sb anodes will provide a new avenue for developing stable alloying-type materials for both LIBs and SIBs.

RESUMEN

Inspirable nano-particles into lungs in the atmosphere were studied in this paper. Field emission scanning electron microscope (FSEM) and X-ray energy dispersive spectrometer were used to investigate the morphology and major constituents of inspirable nano-particles into lungs systematically. The results showed that most of the inspirable nano-particles in the atmosphere are spherical and ellipsoidal, with smooth surface and dense structure. The smaller nano-particles are clustered into loose floccule, with the sizes in the range of 30 to 100 nm. The constant elements in the nano-particles are close consistent with the large particle pollutants, which mainly contain C, O, Al, Si, Na, Mg, K, Ca, Fe, S and Cl etc. The point Analysis of EDS confirmed that the element content of Cl and S in some nano-particles is significantly increased, while others mainly contain C and O. It is believed that the surface of nano inorganic dust particles was adsorbed by the organic pollutants to form the core-shell structure nano-particles pollutants in the process of aerosol formation. Thus, reducing anthropogenic emissions of organic pollutants has great influence on the formation of inspirable nano-particles.

Asunto(s)

RESUMEN

Ionic liquid-modified magnetic polymeric microspheres (ILMPM) were prepared based on Fe3O4 magnetic nanoparticles (MNPs) and ionic liquids (ILs) incorporated into a polymer. The composites were characterized using scanning electron microscopy, Fourier transform infrared analysis, thermogravimetric analysis, X-ray diffraction, and vibrating magnetometer, which indicated that ILMPM had a regularly spherical shape and strong magnetic property. The obtained ILMPM were successfully applied as a special adsorbent of magnetic dispersive solid phase extraction (MDSPE) for the rapid extraction and isolation of sulfamonomethoxine sodium and sulfachloropyrazine sodium in urine. The factors that affected extraction efficiency, such as adsorption conditions, desorption conditions, washing and elution solvents, and pH of the sample solution, were optimized. Under the optimum condition, good linearity in the range of 0.005-2.0 µg g(-1) (r ≥ 0.9996) was obtained for the two sulfonamides (SAs); the average recoveries at three spiked levels ranged from 86.9 to 102.1 %, with relative standard deviations of ≤4.3 %. The presented ILMPM-MDSPE method combined the advantages of ILs, MNPs, and MDSPE and therefore could be potentially applied for rapid screening of SAs in urine.

Asunto(s)

RESUMEN

A novel molecularly imprinted organic-inorganic hybrid polymer (MI-MAA/APTS) based on a dummy molecular imprinting technique and an organic-inorganic hybrid material technique was synthesised and used as a sorbent in solid-phase extraction for the selective isolation and determination of ofloxacin (OFL), lomefloxacin (LOM), and ciprofloxacin (CIP) in tilapia samples. The MI-MAA/APTS sorbent was prepared from 3-aminopropyltriethoxysilanes (APTS) as an inorganic source and methacrylic acid (MAA) as an organic source and exhibited high mechanical strength and special affinities to the analytes. A comparison of MI-MAA/APTS with other conventional sorbents (C18 and HLB) showed that MI-MAA/APTS displayed good selectivity and affinity for OFL, LOM, and CIP, and the recoveries of the analytes at three spiked levels were in the range of 85.1-101.0%, with the relative standard deviations ≤5.1%. The presented MI-MAA/APTS-SPE-HPLC method could be potentially applied to the determination of fluoroquinolones (FQs) in complex fish samples.

Asunto(s)

RESUMEN

A series of metal modified nanoscale Ni-B amorphous alloys was prepared by chemical reduction and tested in the selective hydrogenation of cinnamic acid. A Co modified Ni-B amorphous alloy (Ni-Co-B) exhibited excellent catalytic performance in this reaction with both 100.0% conversion of cinnamic acid and 100.0% selectivity for hydrocinnamic acid under the optimized reaction conditions. X-ray diffraction (XRD) results indicated that the addition of Co had not changed the amorphous structure of Ni-B; whereas, its addition was believed not only to favor decreased agglomeration of the active Ni species, as proven by transmission electron microscopy (TEM), but also to contribute to adsorption of hydrogen itself. Thus, Ni-Co-B showed a larger BET surface area, smaller particle size, and greater number of active species resulting in optimum H2-chemisorption compared to Ni-B and accounting for its excellent catalytic performance in cinnamic acid hydrogenation.

Asunto(s)

RESUMEN

The novel molecularly imprinted microsphere (MIM) that could be applied as special sorbent was synthesized by aqueous suspension polymerization using 1,1-bis(4-chlorophenyl)-1,2,2,2-tetrachloroethane (α-chloro-DDT) as the dummy template. The obtained MIM exhibited good recognition and selectivity to dicofol and it was successfully applied as selective sorbent of solid-phase extraction for the determination of dicofol from aquatic products. At the optimum conditions of the molecularly imprinted solid-phase extraction (MISPE) coupled with GC-ECD, good linearity for dicofol was achieved in a range of 0.4-100 ng g(-1) (r(2)=0.9995) and the recoveries at three spiked levels were ranged from 85.8% to 101.2% for aquatic products with the relative standard deviation (RSD) less than 5.6%. The presented MISPE-GC-ECD method exhibited the advantages of simplicity, selectivity and sensitivity, and could be potentially applied to the determination of dicofol in complicated aquatic products.

Asunto(s)

RESUMEN

In the present paper,with CoCl2 x 6H2O used as precursor, Co-doped ZnO diluted magnetic semiconductor (DMS) crystals were synthesized by hydrothermal method with KOH as mineralizer. The morphology, and the relative content and distribution uniformity of the surface and inner Co element of synthesized crystals were investigated by scanning electron microscope (SEM) and X-ray energy dispersive spectrometry (XREDS), respectively. It was found that Co-doped ZnO crystals with different morphology were yielded, while the bigger crystals showed polar growth charactertistics, and the Co content in the crystal depended on its morphology. The exposed face also changed with crystal morphology. There was more Co in bigger crystals than in smaller ones. Moreover, more Co located in +c (10 11)compared to +c (10 10) exposed face, especially for cone crystals. In addition, it was observed that there was a little amount of cobalt oxide cluster in inner crystal,and the distribution of Co content was relative uniform in both the surface and inner part of the crystal. Cobalt oxide cluster may have effect on the magnetic properties of Co-doped ZnO diulted magnetic semiconductor since Co2+ possesses magnetic property.

Asunto(s)

RESUMEN

Gd2O3: Eu nanocrystal was synthesized by EDTA complexing sol-gel process at relatively low temperature, in which ethylene-diamine-tetraacetic acid (EDTA) and polyethylene glycol (PEG) were used as the chelating agent and disperser respectively. The properties of the nanocrystal were investigated by XRD, SEM, EDS, and fluorescence spectrophotometer. The results show that nanosized, homogenous and pure cubic phase Gd2O3: Eu has been produced after the precursor calcined at 800 degrees C for 2 h. The particles of the Gd2O3: Eu are basically spherical in shape and about 30 nm in size. The main emission peak of Gd2O3: Eu nanocrystal is at 611 nm, resulting in a red emission. Compared with micron scale Gd2O3: Eu phosphors prepared by a conventional method, a clear red shift occurs in the excitation spectrum of Gd2O3: Eu nanocrystal prepared by the present work, and the quenching concentration of Eu has been raised. For this type of nanophosphor, quenching starts at an Eu concentration of 8% (mol%), while a value of 6% was obtained for the conventional one.

Asunto(s)

RESUMEN

The localization of activity of immobilzed papain by covalent-binding was studied by X-ray microanalysis. N alpha-benzoyl-L-arginineamide hydrochloride and FeCl3 served as substrate and capturer respectively. Substrate was catalysed by immobilized papain to produce L-arginine and NH3. NH3 was captured by FeCl3 to form precipitate Fe(OH)3. Precipitation deposited was used to locate active site of immobilized papain. The results show that the macroporous resins carrier of immobilized papain leads to greater enzyme activity, and the distribution of activated enzyme is uniform. Most of activated enzyme was immobilized on the macroporous resins. The optimum condition of localization of activity of immobilized papain was studied.

Asunto(s)