ZnO@ZnFe_2O_4纳米颗粒的制备及其抗菌抗溃疡作用

以铁氰化钾、氯化锌为反应试剂,采用化学共沉淀法,制备了ZnO@ZnFe_2O_4纳米颗粒,通过XRD、TEM、SEM对该纳米颗粒进行了表征,并研究了其抗菌活性和抗溃疡作用.实验结果表明,运用此种方法可以得到构造均匀性质稳定的ZnO@ZnFe_2O_4纳米颗粒,纳米颗粒呈球形,直径为300nm,具有空心结构.XRD检测到ZnO@ZnFe_2O_4的晶相峰,TEM、SEM检测到纳米颗粒的形貌,牛津杯扩散法表明,ZnO@ZnFe_2O_4纳米颗粒具有抗菌性能,最低抑菌浓度为0.04mg/mL,大鼠皮肤溃疡模型表明ZnO@ZnFe_2O_4纳米颗粒具有抗溃疡作用.因此,ZnO@ZnFe_2O_4纳米颗粒可以作为一种潜在的抗溃疡外用药进行开发利用.另外,该纳米颗粒具有空心结构,还可以作为药物载体进行开发利用.

Intensification of levofloxacin sono-degradation in a US/H_2O_2 system with Fe_3O_4 magnetic nanoparticles

Fe3O4 magnetic nanoparticles(MNPs) were synthesised, characterised, and used as a peroxidase mimetic to accelerate levofloxacin sono-degradation in an ultrasound(US)/H2O2 system. The Fe3O4 MNPs were in nanometre scale with an average diameter of approximately 12 to 18 nm. The introduction of Fe3O4 MNPs increased levofloxacin sono-degradation in the US/H2O2 system. Experimental parameters, such as Fe3O4 MNP dose, initial solution p H, and H2O2 concentration, were investigated by a one-factor-at-a-time approach. The results showed that Fe3O4 MNPs enhanced levofloxacin removal in the p H range from 4.0 to 9.0. Levofloxacin removal ratio increased with Fe3O4 MNP dose up to 1.0 g·L-1and with H2O2 concentration until reaching the maximum. Moreover, three main intermediate compounds were identified by HPLC with electrospray ionisation tandem mass spectrometry, and a possible degradation pathway was proposed. This study suggests that combination of H2O2, Fe3O4 MNPs and US is a good way to improve the degradation efficiency of antibiotics.

Synthesis and Characterization of Superparamagnetic Fe₃O₄@SiO₂Core-Shell Composite Nanoparticles

The Fe3O4@SiO2 composite nanoparticles were obtained from as-synthesized magnetite (Fe3O4) nanoparticles through the modified St?ber method. Then, the Fe3O4 nanoparticles and Fe3O4@SiO2 composite nanoparticles were characterized by means of X-ray diffraction (XRD), Raman spectra, scanning electron microscope (SEM) and vibrating sample magnetometer (VSM). Recently, the studies focus on how to improve the dispersion of composite particle and achieve good magnetic performance. Hence effects of the volume ratio of tetraethyl orthosilicate (TEOS) and magnetite colloid on the structural, morphological and magnetic properties of the composite nanoparticles were systematically investi-gated. The results revealed that the Fe3O4@SiO2 had better thermal stability and dispersion than the magnetite nanoparticles. Furthermore, the particle size and magnetic property of the Fe3O4@SiO2 composite nanoparticles can be adjusted by changing the volume ratio of TEOS and magnetite colloid.

Calculation of photon attenuation coefficient and dose rate in concrete with the addition of SiO_2 and MnFe_2O_4 nanoparticles using MCNPX code and comparison with experimental results

One of the most important safety features of nuclear facilities is the shielding material used to protect the operating personnel from radiation exposure. The most common materials used in radiation shielding are concretes. In this study, a Monte Carlo N-Particle eXtended code is used to calculate the gamma-ray attenuation coefficients and dose rates for a new concrete material composed of MnFe_2O_4 nanoparticles, which is then compared with the theoretical and experimental results obtained for a SiO_2 nanoparticle concrete material. According to the results, the average relative differences between the simulations and the theoretical and experimental results for the linear attenuation coefficient(l) in the SiO_2 nanoparticle materials are 6.4% and 5.5%, respectively. By increasing the SiO_2 content up to 1.5% and the temperature of MnFe_2O_4 up to 673 K, l is increased for all energies. In addition, the photon dose rate decreases up to 9.2% and3.7% for MnFe_2O_4 and SiO_2 for gamma-ray energies of0.511 and 1.274 MeV, respectively. Therefore, it was concluded that the addition of SiO_2 and MnFe_2O_4 nanoparticles to concrete improves its nuclear properties and could lead to it being more useful in radiation shielding.

Comparable Studies of Adsorption and Magnetic Properties of Ferrite MnFe_2O_4 Nanoparticles,Porous Bulks and Nanowires

The spinel ferrites MnFe2O4 nanowires were synthesized by hydrothermal route,porous MnFe2O4 and nanoparticles morphologies were synthesized by sol-gel method with egg white.The structures,morphologies,magnetic properties and adsorption properties of these obtained ferrites with different morphologies were studied contrastively.Results show that the obtained samples exhibit ferromagnetic properties.This realizes convenient magnetic separation from solution when they are used in the treatment of organic dyes wastewater.However,the contrastive studies show that the saturation magnetizations（Ms） of MnFe2O4 with different morphologies are different and the Ms follows the order：Ms（porous）〈Ms（nanoparticles）〈Ms（nanowires）.In addition,the adsorptions of methylene blue（MB） onto these ferrites depend on ferrites＇ morphologies seriously.The adsorption rate of MB on the porous MnFe2O4 is much higher than those onto the other two samples because the porous structure can provide high efficient mass transport through the pores.

Controlled Preparation of Monodisperse CoFe_2O_4 Nanoparticles by a Facile Method

CoFe2O4 nanoparticles （NPs） were synthesized by coprecipitation method using FeCl3·6H2O and CoCl2·6H2O as precursors.The synthesized conditions were optimized,such as added means of precipitator,quantity of precipitator,the mol ratio of Fe 3＋ to Co2＋,reaction temperature and pH value.The synthesized material was characterized by XRD,TEM,FTIR,EDS,Raman and its magnetic properties were studied by VSM.The experimental results confirm that the sample is cubic spinel structure CoFe2O4 with a narrow size distribution and a good dispersion feature.CoFe2O4 NPs with well-controlled shape and size was obtained at 70℃.The magnetic properties indicate superparamagnetic behavior and good saturated magnetization.

Synthesis of Mn_xZn_(1-x)Fe_2O_4 Nanoparticles by Ball-milling Hydrothermal Method

SMnxZn1-xFe2O4 （x=1,0.9,0.8,0.7,0.6,0.5,0.25,0） nanoparticles were prepared by ball-milling hydrothermal and investigated by X-ray diffraction, DTG and TEM. Nanocrystallite grain size was determined by X-ray linewidth to be from 63 A to 274 A. The thermal properties indicate absorbed water still remain at low temperature, crystalline wate will be decomposed from 230 ℃ to 260 ℃, partial Mn^2＋ will be oxidized near 730 ℃. TEM shows the ferrite particles pocess a spherical morphology and uniform nanosize.

Synthesis of Cobalt Chromite Nanoparticles by Thermolysis of Mixed Cr^(3+) and Co^(2+) Chelates of 2-Mercaptopyridin N-Oxide

Pure greenish-blue cobalt chromite(Co Cr/_2O_4) nanoparticles with narrow particle range of 4.1±1.9nm and surface area of 78.2 m2·g-1were synthesized through mixed chelates thermolysis of corresponding metals using 2-Mercaptopyridine N-oxide sodium salt as chelating agent. During the thermolysis procedure,high amount of gases were emitted that led to the formation of nanoparticles with high surface area. The product was characterized by TGA, DTG, XRD, TEM, SEM, LLS, BET and chemical analysis. Design of experiments was performed to fulfill the two levels L_4 Taguchi design. It was found that the temperature and time of thermolysis process have significant effect on the particle size reduction. The Oxidation of trichloroethylene was carried out over Co Cr_2O_4 nanocrystallite. Catalytic activity analysis revealed that the synthesis Co Cr_2O_4 possesses high catalytic activity for this process.

Solid State Reactions in Cr₂O₃-ZnO Nanoparticles Synthesized by Triethanolamine Chemical Precipitation

The present work reports the preliminary results about solid state reactions of Cr-ZnO solid solutions and ZnCr2O4 nanometric particles obtained with triethanolamine (TEA). Different compositions were prepared from 0.65 to 33.3 at % chromium, the last one corresponding to ZnCr2O4 cubic spinel composition. Fourier Transform Infrared Spectroscopy (FTIR) together with X-ray diffraction (XRD) patterns of powders with Cr3+ between 0.65 and 16.0 at % were assigned to Cr-ZnO solid solution due to the only presence of ZnO structure, FTIR spectra indicating that Cr-O bonding exists even if there was no presence of ZnCr2O4. With low chromium atomic percent, lattice parameters increase, but as the chromium content exceeds of 3 at %, there is basically no further expansion of the cell. From Williamson-Hall and Rietveld methods the lattice dimensions were assigned to chromium incorporation in ZnO structure and the lattice contraction by particle size refinement. After annealing all samples from 0.65 to 16.0 at % at 400°C in oxygen, the analysis showed that nanoparticles of Cr-ZnO solid solution still remain.

Fabrication and magnetic transformation from paramagnetic to ferrimagnetic of ZnFe2O4 hollow spheres

ZnFe2O4 hollow spheres (ZFHs) with sizes of 200-302 nm were synthesized by simple impregnating method using the as-prepared phenolic formaldehyde (PF) spheres as templates and subsequent annealing at 500-700 ℃. The prepared ZFHs are assembled by a large number of small nanoparticles with sizes of 15-20 nm, and many mesopores exist among these nanoparticles. The samples annealed at 500-550℃ exhibit a single cubic spinel structure, while higher annealing temperature leads to the formation of hexagonal ZnO and rhombohedral α-Fe2O3 secondary phases. The size of the assembled nanoparticles increases with the increase in annealing temperature. Novel magnetic transformation from paramagnetic to ferrimagnetic is induced by the reduction of annealing temperature and the saturation magnetization significantly increases from 2.3 to 13.5 A·m^2/kg. The effect of the formation of hollow sphere structure on the redistribution of Fe^3+ and Zn^2+ in the spinel structure was studied.

Fabrication and Microwave Absorption Properties of Fe_(0.64)Ni_(0.36)-NiFe_2O_4 Nanocomposite

Fe_(0.64)Ni_(0.36)-NiFe_2O_4 nanocomposite was performed with partially reducing NiFe_2O_4 nanoparticles in Ar/H_2 ambient.The microwave and static magnetic properties were investigated.The results showed that the nanocomposite was characterized with enhanced microwave absorption properties.The optimal reflection loss(RL)of the nanocomposite reached-24.8 dB at 14 GHz for an absorber thickness of 1.5 mm.Meanwhile,a broad bandwidth for RL<-10 dB was obtained in the range of 3.1—15.1 GHz for an absorber thickness from1.0 to 4.0 mm.The enhancement is attributed to the increase of dielectric and magnetic loss after reducing procedure.

Synthesis of Cu nanoparticles by chemical reduction method

Cu nanoparticles (CuNPs) have been synthesized through an easy route by chemical reduction at room temperature. The Cu^2+ ions were reduced and stabilized with sodium borohydride and polyvinylpyrrolidone, respectively. The effect of the variation of the reducing agent/precursor-salt (RA/PS) ratio on the size and morphology of the CuNPs was evaluated. The synthesized material was studied by ultraviolet-visible (UV-Vis) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The UV-Vis spectra showed a CuNPs plasmon peak at 569 nm and another peak belonging to Cu2O at 485 nm. XRD analysis showed the fcc-Cu phase with a small amount of fcc-Cu2O compound. SEM and TEM studies displayed that small semispherical CuNPs of approximately 7 nm were obtained at the RA/PS ratio of 2.6. The excess of polyvinylpyrrolidone stabilizer played an essential role in preventing CuNPs oxidation. On the other side, Cu2O polyhedral particles with larger sizes up to 150 nm were identified in the RA/PS ratio range of 2.0-1.84. In addition, Cu2O particles having star morphologies with quantum confinement at their tips were obtained at the RA/PS ratio of 1.66.

ZnO@ZnFe2O4乳膏的制备工艺及皮肤用药安全性评价

目的研究ZnO@ZnFe2O4乳膏的制备工艺及皮肤用药的安全性。方法采用正交试验方法优选ZnO@ZnFe2O4乳膏的成型工艺;采用Buehler试验,观察豚鼠皮肤接触ZnO@ZnFe2O4乳膏后的过敏情况;将ZnO@ZnFe2O4乳膏单次或多次涂于新西兰兔完整及破损皮肤处,观察药物对皮肤的刺激情况;新西兰兔皮肤单次给药观察药物的急性毒性。结果 ZnO@ZnFe2O4乳膏的最佳工艺条件:乳化剂的用量为6%,乳化时间为20 min,搅拌速度为1 600 r·min^-1,乳化温度为80℃;采用最佳工艺制备的ZnO@ZnFe2O4乳膏对豚鼠皮肤未产生致敏反应,对兔皮肤未产生刺激性,对兔皮肤未引起急性毒性反应。结论 ZnO@ZnFe2O4乳膏经皮给药安全可靠。

Synthesis of Fe_3O_4@SiO_2@polymer nanoparticles for controlled drug release

Novel multifunctional nanoparticles containing a magnetic Fe3O4@SiO2 sphere and a biocompatible block copolymer poly(ethylene glycol)-b-poly(aspartate)(PEG-b-PAsp) were prepared.The silica coated on the superparamagnetic core was able to achieve a magnetic dispersivity,as well as to protect Fe3O4 against oxidation and acid corrosion.The PAsp block was grafted to the surface of Fe3O4@SiO2 nanoparticles by amido bonds,and the PEG block formed the outermost shell.The anticancer agent doxorubicin(DOX) was loaded into the hybrid nanoparticles via an electrostatic interaction between DOX and PAsp.The release rate of DOX could be adjusted by the pH value.

Removal of benzotriazole by heterogeneous photoelectro-Fenton like process using ZnFe_2O_4 nanoparticles as catalyst

ZnFe2O4 nanoparticles （ZFNPs） were developed as catalyst for the degradation of benzotriazole （BTA） by heterogeneous photoelectro- Fenton （PE-Fenton） like process. ZFNPs were prepared by a co-precipitation process and then characterized with transmission electron microscopy （TEM）, X-ray fluorescence （XRF）, X-ray diffraction （XRD） and BET surface area. Using such ZFNPs as catalyst, the degradation of BTA was investigated. Due to the high catalytic activity of ZFNPs, PE-Fenton like process showed efficient degradation of BTA. The influencing factors such as pH, dosage of ZFNPs, applied potential and initial concentration of BTA were systematically investigated. Under the optimum conditions, 91.2% of BTA was removed after 180 rain treatment.

Synthesis of NiFe_2O_4 nanoparticles by a low temperature microwave-assisted ball milling technique

Nanocrystalline NiFe2O4 particles with mean size of about 20 nm were directly synthesized by a novel microwave-assisted ball-milling approach, using basic nickel carbonate and iron powders as the raw materials. The results showed that an interme- diate product Fe2Ni2（OH）sCO3 · 2H2O was formed by milling NiCO3 · 2Ni（OH）2· 4H2O and Fe powders with microwave assis- tance, then this intermediate product further reacted to form NiFe2O4 nanocrystals. On the other hand, by using NiO and Fe2O3 as the raw materials, NiFe2O4 could not be able to form. NiFe2O4 nanocrystals could be directly synthesized without post-sintering by this process. This makes it a new promising approach for ferrite nanoparticle, which is simple and environ- mentally friendly.

A highly selective magnetic sensor with functionalized Fe/Fe_3O_4 nanoparticles for detection of Pb^(2+)

A magnetic sensor for detection of Pb^2＋ has been developed based on Fe/Fe3O4 nanoparticles modified by3-（3,4-dihydroxyphenyl）propionic acid（DHCA）. The carboxyl groups of DHCA have a strong affinity to coordination behavior of Pb^2＋ thus inducing the transformation of Fe/Fe3O4 nanoparticles from a dispersed to an aggregated state with a corresponding decrease, then increase in transverse relaxation time（T2） of the surrounding water protons. Upon addition of the different concentrations of Pb^2＋ to an aq. solution of DHCA functionalized Fe/Fe3O4 nanoparticles（DHCA-Fe/Fe3O4 NPs）（[Fe] = 90 mmol/L）, the change of T2 values display a good linear relationship with the concentration of Pb^2＋ from 40 μmol/L to 100 μmol/L and from 130 μmol/L to 200 μmol/L, respectively. Owing to the especially strong interaction between DHCA and Pb^2＋, DHCA-Fe/Fe3O4 NPs exhibited a high selectivity over other metal ions.

3DRGO-NiFe2O4/NiO nanoparticles for fast and simple detection of organophosphorus pesticides

The residues of organophosphorus pesticide(OPs)on fruits and vegetables pose a threat to human health,so it is very meaningful to explore simple and fast detect methods for OPs residual.In this work,nickel ferrite/nickel oxide nanoparticles co-loaded three-dimensional reduced graphene oxide(3DRGONiFe2O4/NiO NPs),as a new low cost nanocomposite,was prepared.Based on its high performance mimetic peroxidase activity,a colorimetric method for the detection of OPs has been developed.Dichlorvos was chosen as model compounds to evaluate the detection performance.The detection linear range for dichlorvos is from 50μg/mL to 2.5×10^4μg/mL with a detection limit of 10μg/mL.Furthermore,a test paper can be developed based on the 3 DRGO-NiFe2O4/NiO NPs for visual detection of dichlorvos,and the image information of the paper sensor can be converted into digital signal and quantitative detection by a smartphone.Notably,this method can also be used to detect dichlorvos in real samples,including vegetables and fruits.Thus,the developed naked assay holds great potential in simple,inexpensive and rapid detection of OPs in fruit and vegetable samples.

Co-adsorption of gaseous benzene, toluene, ethylbenzene,m-xylene(BTEX) and SO_2 on recyclable Fe_3O_4 nanoparticles at 0–101% relative humidities

We herein used Fe3O4 nanoparticles（NPs） as an adsorption interface for the concurrent removal of gaseous benzene, toluene, ethylbenzene and m-xylene（BTEX） and sulfur dioxide（SO2）, at different relative humidities（RH）. X-ray diffraction, Brunauer-Emmett-Teller, and transmission electron microscopy were deployed for nanoparticle surface characterization.Mono-dispersed Fe3O4（Fe2O3·Fe O） NPs synthesized with oleic acid（OA） as surfactant, and uncoated poly-dispersed Fe3O4 NPs demonstrated comparable removal efficiencies.Adsorption experiments of BTEX on NPs were measured using gas chromatography equipped with flame ionization detection, which indicated high removal efficiencies（up to（95 ± 2）%） under dry conditions. The humidity effect and competitive adsorption were investigated using toluene as a model compound. It was observed that the removal efficiencies decreased as a function of the increase in RH, yet, under our experimental conditions, we observed（40 ± 4）% toluene removal at supersaturation for Fe3O4 NPs, and toluene removal of（83 ± 4）% to（59 ± 6）%, for OA-Fe3O4 NPs. In the presence of SO2, the toluene uptake was reduced under dry conditions to（89 ± 2）% and（75 ± 1）% for the uncoated and coated NPs, respectively, depicting competitive adsorption. At RH 〉 100%,competitive adsorption reduced the removal efficiency to（27 ± 1）% for uncoated NPs whereas OA-Fe3O4 NPs exhibited moderate efficiency loss of（55 ± 2）% at supersaturation.Results point to heterogeneous water coverage on the NP surface. The magnetic property of magnetite facilitated the recovery of both types of NPs, without the loss in efficiency when recycled and reused.

Synthesis and Properties of Monodisperse Superparamagnetic Mg_(0.8)Mn_(0.2)Fe_2O_4 Nanoparticles Using Polyol Reflux Method

Superparamagnetic monodisperse Mg0.8Mn0.2Fe2O4 nanoparticles have been successfully synthesized in liquid polyol at elevated temperature of 200 °C. Diethylene glycol（DEG） used here plays dual role in synthesis as it acts as reducing agent and alternatively coats the surface of nanoparticles while synthesis and thereby maintaining uniform size and dispersibility. Powder X-ray diffraction（XRD） and magnetic measurements showed that the sample is cubic spinel and superparamagnetic at room temperature. Raman spectra confirmed the formation of the Mg0.8Mn0.2Fe2O4 nanoparticles.The nanoparticles exhibit very good stability in water due to in situ coating with DEG molecules.