铁酸锶镧对CH4化学循环转化中Mn3O4氧化还原性能的作用机制

通过水热合成法制备了MnO₂，以其作为锰源通过热分解得到Mn₃O₄，采用溶胶凝胶法制备了Mn₃O₄/La_0.8Sr_0.2FeO₃，将Mn₃O₄和Mn₃O₄/La_0.8Sr_0.2Fe O₃在900℃下与体积分数3%的CH₄和空气交替接触，模拟化学循环燃烧中的氧化还原过程，研究了Mn₃O₄和Mn₃O₄/La_0.8Sr_0.2Fe O₃的氧化还原性能和长期稳定性。结果表明：温度的升高会提高Mn₃O₄/La_0.8Sr_0.2<...     

MnOx@Fe3O4复合材料制备及其对苯酚处理性能研究

首先采用两步法设计制备磁性纳米复合材料MnO_x@Fe₃O₄,然后测量其粒度的分布状态，再通过扫描电镜(SEM)、X-射线衍射(XRD)和红外光谱(IR)3种方法表征其结构形态；初步研究了纳米复合物分子MnO_x@Fe₃O₄结构与组成，深入分析了该磁性纳米复合材料的添加量和改变苯酚的初始浓度对该复合材料活化PMS分解苯酚性能的影响，并研究了纳米复合材料MnO_x@Fe₃O₄循环使用的效果。结果表明，纳米复合材料MnO_x@Fe₃O₄是α-MnO₂表面负载四氧化铁(Fe₃O₄)的复合材料，平均粒径为247.3 nm,磁分离性好；纳米复合材料MnO_x@Fe₃O₄有较好的活化PMS分解苯酚的效果，在处理初始浓度...     

Mn3O4-MnOOH复合材料催化过硫酸氢钾降解罗丹明B

在碱性条件下，使用H₂O₂部分氧化Mn(OH)₂制备了Mn₃O₄-MnOOH复合材料，并将其作为过硫酸氢钾活化剂用于催化氧化降解水中难降解染料罗丹明B。采用X射线衍射仪(XRD)、X射线光电子能谱(XPS)、扫描电镜(SEM)、透射电镜(TEM)等多种手段表征了材料的物理化学性质，确定了其为内部Mn₃O₄、外部MnOOH的二元纳米片状核壳式结构。通过考察不同催化体系下罗丹明B的降解效果可得Mn₃O₄-MnOOH复合材料具有比单一锰氧化物更好的催化效能。在此基础上，进一步考察溶液初始pH、催化剂投加量、KHSO₅投加量、污染物浓度等因素对染料降解的影响，确定了适宜的反应条件，即pH为4，催化剂投加质量浓度为0.1 g/L,KHSO₅投加浓度为0.325 0 mmol/L，污染物初始质量浓度为50 mg/L，该条件下，反应30 min后，罗丹明B去除率...     

聚乙二醇/聚乙烯吡咯烷酮修饰的纳米Fe3O4粒子的制备与表征

为了获得能够在水中稳定分散,具有广泛应用前景的磁性纳米粒子,以不同分子量的聚乙烯吡咯烷酮(PVP)作为修饰剂,在聚乙二醇(PEG)中高温热分解乙酰丙酮铁(Fe(acac)₃)制备了纳米Fe₃O₄粒子。采用X射线粉末衍射仪(XRD)、透射电镜(TEM)、高分辨透射电镜(HRTEM)、超导量子干涉仪(SQUID)、热重分析仪(TGA)、傅里叶变换红外光谱仪(FT-IR)、纳米粒度与zeta电位分析仪对样品进行了表征,并对样品在生理盐水和生理缓冲液中的稳定性进行了研究,结果表明:制备的纳米Fe₃O₄粒子具有高的结晶度以及单分散性,在300 K下,具有超顺磁性和较高的饱和磁化强度;PEG和PVP共同修饰于纳米Fe₃O₄粒子表面,为纳米Fe₃O₄粒子提供了良好的水分散性;制备的纳米Fe₃O₄粒子在生理盐水和多种生理缓冲液中能够高度溶解并稳定地分散。水中的纳米Fe₃O₄粒子表面呈电中性,表面修饰层的空间位阻效应是所制备的纳米粒子在水溶液中高分散的原因。     

纳米复合材料Fe3O4@RGO@C18对四环素的吸附研究

将制备的Fe₃O₄磁性粒子外层包裹了一层RGO(石墨烯)，又继续在Fe₃O₄@RGO材料表面修饰了C₁₈，从而得到了Fe₃O₄@RGO@C₁₈纳米材料。对所制备的样品材料进行形貌、结构等的表征，并对水中的四环素进行了吸附实验的研究。通过对Fe₃O₄@RGO@C₁₈纳米材料的红外线光谱检测，扫描电子显微镜检测，透射电子显微镜，能谱，磁性进行表征，同时用磁性纳米材料吸附水中的四环素，考察了溶液p H、反应温度、震荡时间、初始四环素的浓度等因素对吸附过程的影响。研究结果表明Fe₃O₄@RGO@C₁₈纳米粒子为具有类三明治结构的核壳结构且分散均匀，复合效果好，粒径很小。当pH为7、温度为25℃、振荡时间为40 min、四环素的质量浓度为80 mg/L时为最佳条件，吸附量为77.56 mg/g...     

亲油性纳米Fe3O4的制备及其在含油污水处理中的研究

采用化学共沉淀法制备出纳米 Fe₃O₄,并用纳米 Fe₃O₄处理含油污水。通过 TEM、XRD 和 FT- IR 的表征,确定 Fe₃O₄的粒径大小与均匀状况,以及纳米 Fe₃O₄的晶格纯度和亲油性。通过改变反应时间、反应温度、搅拌速度和磁场励磁电流,确定纳米 Fe₃O₄处理含油污水最佳除油条件。     

Preparation of magnetic Fe3O4 nano-particles modified with oleic acid at low-temperature and washed with distilled water

通过对油酸改性四氧化三铁（Fe₃O₄）磁性纳米粒子的制备工艺的改进研究,成功制备了分散性好、磁响应性强的平均粒径在18 nm的改性Fe₃O₄磁性纳米粒子,并通过X射线衍射、红外光谱、透射电镜等对制备的磁性纳米粒子进行了表征。结果表明：当采用60 ℃的反应温度进行改性处理,以蒸馏水进行洗涤时,得到的油酸改性Fe₃O₄磁性纳米粒子的分散性最好、磁响应性最强。     

ZnFe2O4/TiO2纳米棒光催化剂的制备及其对甲基橙废水的脱色研究

采用水热法制备了ZnFe₂O₄纳米粒子,在碱性条件下水解钛酸丁酯组装得到ZnFe₂O₄/TiO₂纳米棒光催化剂,利用X-射线衍射仪(XRD)、扫描电镜(SEM)、振动样品磁强计(VSM)、N₂吸附-脱附仪及电化学工作站分别表征了ZnFe₂O₄/TiO₂纳米棒的晶型、形貌、磁性能、孔结构及电极性能,并研究了其对甲基橙废水的脱色效果。结果表明,ZnFe₂O₄具有尖晶石结构,而TiO₂是锐钛矿结构,二者组装为具有介孔结构的ZnFe₂O₄/TiO₂纳米棒光催化剂,比饱和磁化强度高达40.0 emu·g^-1;紫外光照射120 min后,ZnFe₂O₄/TiO₂纳米棒对甲基橙废水的脱色率...     

PANI/Fe3O4复合材料的制备及其应用

介绍了以Fe₃O₄纳米粒子为核,用导电高分子材料聚苯胺(PANI)包裹成的PANI/Fe₃O₄核壳结构多功能全新复合材料,其不仅具有比表面积大、粒径小等优点,更具有吸附活性高、吸附容量大等性能,在污水处理、超级电容器等领域得到了广泛应用。对该复合材料的应用和发展进行了展望。     

Mn3O4催化协同低温等离子体再生处理工业废活性炭的研究

通过Mn₃O₄催化协同低温等离子体再生废活性炭,考察了放电电压、气体流速、放电时间对甲苯降解率的影响。结果表明,Mn₃O₄催化协同低温等离子体提高甲苯降解率,在电压为12 kV、气体流速为0.5 L/min,放电时间为30 min时,降解率达到最大,为99.78%。通过对吸附复杂污染物的工业废活性炭的研究,Mn₃O₄催化协同低温等离子体提高了VOCs的降解率,表明Mn₃O₄催化协同低温等离子体方法可行。     

Preparation of chitosan bicomponent nanofibers filled with hydroxyapatite nanoparticles via electrospinning

Chitosan (CS) bicomponent nanofibers with an average diameter controlled from 100 to 50 nm were successfully prepared by electrospinning of CS and poly(vinyl alcohol) (PVA) blend solution. Finer fibers and more efficient fiber formations were observed with increased PVA contents. On this contribution, a uniform and ultrafine nanofibrous CS bicomponent mats filled with hydroxyapatite (HA) nanoparticles were successfully electrospun in a well devised condition. An increase in the contents of HA nanoparticles caused the conductivity of the blend solution to increase from 1.06 mS/cm (0 wt % HA) to 2.27 mS/cm (0.5 wt % HA), 2.35 mS/cm (1.0 wt % HA), respectively, and the average diameter of the composite fibers to decrease from 59 ± 10 nm(0 wt % HA) to 49 ± 10 nm (0.5 wt % HA), 46 ± 10 nm (1.0 wt % HA), respectively. SEM images showed that some particles had filled in the nanofibers whereas the others had dispersed on the surface of fibers, and EDXA results indicated that both the nanoparticles filled in the nanofibers and those adhered to the fibers were HA particles. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Surfactant‐free nanoparticles of poly(DL‐lactide‐co‐glycolide) prepared with poly(L‐lactide)/ poly(ethylene glycol)

Surfactant‐free nanoparticles of poly(DL ‐lactide‐co‐glycolide) (PLGA) nanoparticles were prepared with or without poly(L ‐lactide)‐poly(ethylene oxide) (LE) diblock copolymer (abbreviated as PLGA/LE and PLGA nanoparticles) by dialysis method. LE diblock copolymer was used to make PLGA nanoparticles to alternate conventional surfactant. The size of PLGA and PLGA/LE nanoparticles was 295.3 ± 171.3 and 307.6 ± 27.2 nm, respectively, suggesting LE diblock copolymer might be coated onto the surface of nanoparticles. Observation of scanning electron microscope (SEM) showed that PLGA/LE nanoparticles have spherical shapes ranging ～ 200–500 nm. In ¹H‐NMR study, characteristic peaks of the methyl protons of PLGA disappeared in D₂O, whereas characteristic peaks of the methyl proton of both PEG and PLGA were shown in both CDCl₃ and D₂O, indicating that LE diblock copolymer coated on the surface of the PLGA nanoparticles. The higher the initial content of drug, the higher the drug contents and the lower the loading efficiency. PLGA/LE nanoparticles at higher drug contents resulted in slower adriamycin·HCl (ADR) release rate than that of lower drug contents. Also, slower release rate of ADR was achieved by entrapped into the PLGA/LE nanoparticles, whereas LE polymeric micelles showed rapid ADR release. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1116–1123, 2003     

Microstructure evolution and advanced performance of Mn3O4 nanomorphologies

Mn(3)O(4) morphologies with tetragonal single-crystal nanostructures including nanoparticles, nanorods and nanofractals were successfully prepared by a widely applicable chemical reaction route. The morphologies were synthesized using the reactants MnCl(2)·4H(2)O, H(2)O(2), and NaOH in a suitable surfactant and alkaline solution. The dripping speed of the NaOH solution plays an important role in the microstructure evolution of Mn(3)O(4) morphologies. The difference in the dripping speed of NaOH solutions leads to different Mn(3)O(4) nanomorphologies, which are called nanoparticles, nanorods and nanofractals. The average grain size of the Mn(3)O(4) nanoparticles ranged from a few to several tens of nanometers. The Mn(3)O(4) nanorods were smooth, straight, and the geometrical shape was structurally perfect. Their lengths ranged from several hundred nanometers to a few micrometers, and their diameters ranged from 10 nm to 30 nm. The fractal branches of the Mn(3)O(4) nanofractals were a few micrometers in length and several hundred nanometers in width. The catalytic properties of these Mn(3)O(4) nanomorphologies for the degradation of phenol were evaluated in detail. The results indicated that the Mn(3)O(4) nanofractals possess remarkable catalytic activity for the degradation of phenol in water treatment.     

Electron Beam Synthesis and Characterization of Poly Vinyl Alcohol/Poly Acrylic Acid Embedded Ni and Ag Nanoparticles

Electron beam irradiation was applied to prepare poly (vinyl alcohol) and poly (acrylic acid) P (PVA/AAc) containing nickel and silver nanoparticles. The prepared P (PVA/AAc)–Ni and P (PVA/AAc)–Ag nanoparticles were characterized by Fourier-transform infrared, UV–Visible spectroscopy, X-ray diffraction (XRD) and transmission electron microscope (TEM). The electrical conductivity and thermal gravimetrical analysis (TGA) have been investigated. Bacterial sensitivity toward nickel and silver nanoparticles was studied. The XRD and TEM confirmed that by increasing the Ni or Ag contents from 10 to 150?mmol in the copolymers, the metal particle size increases from 27.6 to 45.6?nm for Ni and from 14.8 to 37.4?nm for Ag. Meanwhile, the mean size particle increases from 33.02 to 45.05?nm for Ni and from 15.5 to 44.03?nm for Ag. The electrical conductivity of the polymer containing Ag is higher than that of Ni and it increased by increasing the metal content. The TGA studies confirmed that, the thermal stability increase by the introduction of metal into polymeric complex. Bacterial sensitivity to metal nanoparticles was found to vary depending on the microbial species. Disc diffusion studies with P. aeruginosa, E. coli and K. pneumoniae revealed greater effectiveness of the silver nanoparticles compared to the nickel nanoparticles, S. aureus depicted the highest sensitivity to nanoparticles compared to the other strains and was more adversely affected by the nickel nanoparticles.     

Investigation on characterization and transfection of a novel multi‐polyplex gene delivery system

pDNA was condensed by polycationic peptide polylysine (PLL) to form a core, and then encapsulated in biodegradable monomethoxy (poly ethylene glycol)-poly(lactide-co-glycolide)-monomethoxy (poly ethylene glycol) (PELGE) to form core-shell nanoparticles (NPs) as a novel multi-polyplex gene delivery system—PPD(PELGE-PLL-DNA). NPs were prepared by a double emulsification-solvent evaporation technique, using F68 (Pluronic F68, namely Poloxamer 188) as surfactant (not traditional stabilizer PVA), and characterized by morphology, particle size, zeta potential, nuclease, and sonication protection ability, as well as transfection efficiency. Results showed that PPD had a regular spherical shape, with an average diameter of 155 ± 2.97 nm and a zeta potential of −25.6 ± 1.35 mV. PPD could protect plasmid DNA from nuclease degradation and sonication during preparation, while the transfection efficiencies in HepG2 cells and Hela cells were much higher than that of NPs without PLL. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

羧甲基淀粉包覆Fe_3O_4磁性纳米颗粒的制备与表征

利用共沉淀法制备了CMS@Fe3O4磁性纳米颗粒。利用扫描电子显微镜、红外光谱、Zeta电位分析仪以及振动样品磁强计表征了纳米颗粒的形态以及性质。磁性纳米颗粒类似于球状,平均直径为(35±10)nm。结果表明,在较高的pH范围内粒子有较高的负电顺磁性。30 d后考察了CMS@Fe3O4磁性纳米颗粒的稳定性,CMS@Fe3O4磁性纳米颗粒在pH值为11时保持较好的稳定性。     

Preparation and antibacterial effects of PVA‐PVP hydrogels containing silver nanoparticles

The poly(vinyl alcohol)/poly(N‐vinyl pyrrolidone) (PVA–PVP) hydrogels containing silver nanoparticles were prepared by repeated freezing–thawing treatment. The silver content in the solid composition was in the range of 0.1–1.0 wt %, the silver particle size was from 20 to 100 nm, and the weight ratio of PVA to PVP was 70 : 30. The influence of silver nanoparticles on the properties of PVA–PVP matrix was investigated by differential scanning calorimeter, infrared spectroscopy and UV–vis spectroscopy, using PVA–PVP films containing silver particles as a model. The morphology of freeze‐dried PVA–PVP hydrogel matrix and dispersion of the silver nanoparticles in the matrix was examined by scanning electron microscopy. It was found that a three‐dimensional structure was formed during the process of freezing–thawing treatment and no serious aggregation of the silver nanoparticles occurred. Water absorption properties, release of silver ions from the hydrogels and the antibacterial effects of the hydrogels against Escherichia coli and Staphylococcus aureus were examined too. It was proved that the nanosilver‐containing hydrogels had an excellent antibacterial ability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 125–133, 2007     

Emulsion polymerization of pentabromobenzyl acrylate: effect of reaction parameters on the produced flame‐retardant nanoparticles

Flame‐retardant nanoparticles of sizes ranging between 33 ± 6 and 460 ± 50 nm were formed by the emulsion polymerization of the pentabromobenzyl acrylate (PBBA) monomer in the presence of sodium dodecyl sulfate as the surfactant and potassium persulfate as the initiator. The effect of various polymerization parameters, e.g. monomer, crosslinker monomer, initiator and surfactant concentrations, on the size, size distribution and polymerization yield of the poly(pentabromobenzyl acrylate) nanoparticles produced has been elucidated. Poly(pentabromobenzyl acrylate)/polystyrene (PPBBA/PS) nanoblends containing 15% and 70% of PPBBA particles of 33 ± 6 and 460 ± 50 nm diameter were prepared by mixing the particles with a PS solution in methylene chloride, followed by evaporation of the methylene chloride from the mixture. The effect of the size and the content of the PPBBA nanoparticles in the nanoblends on the thermal stability of the PS were also elucidated. Copyright © 2011 Society of Chemical Industry     

Radiation Preparation of Conducting Nanocomposite Membrane Based on (Copper/Polyacrylic Acid/Poly Vinyl Alcohol) for Rapid Colorimetric Sensor of Mercury and Silver Ions

In this study, poly acrylic acid/poly vinyl alcohol capped copper as nanocomposite membrane Cu–(PAAc/PVA) has been prepared using gamma radiation. Aqueous solution of 0.2 mol Cu²⁺ ions chemically reduction using ascorbic acid and PAAc/PVA as stabilizer. Cu²⁺ ions could be deposited uniformly on the matrix network of PAAc/PVA membrane. The resulting Cu–(PAAc/PVA) nanocomposites membrane exhibited rapid colorimetric detection of mercury and silver ions associated with notable color changes of the membrane from yellow to pale gray and dark green, respectively. A novel label colorimetric sensor membrane Cu–(PAAc/PVA) has been developed for sensitive detection of Hg²⁺, Ag⁺ ions basis of the UV spectrophotometer data. A detection limit as low as 10^?5 and 10^?6 M of Hg²⁺ and Ag⁺ ions was achieved. This article proved that the Cu–(PAAc/PVA) nanocomposites membrane is exhibited excellent selectivity toward Hg²⁺, Ag⁺ ions. The advantages to the determination of Hg²⁺, Ag⁺ ions using Cu(PAAc/PVA) nanocomposite membrane is simple, low cost, rapid and easy observation by naked eye, the developed Cu–(PAAc/PVA) colorimetric membrane candidate for the detection of toxic Hg²⁺, Ag⁺ ions in environmental and biological samples. The particles size of synthesized Cu was performed using Transmission electron microscopy (TEM) indicates that Cu nanoparticles of size 8 nm are formed by green method. Absorption spectra of Cu nanoparticles deposited in PAAc/PVA at 591 nm confirm the capped of Cu nanoparticles inside PAAc/PVA matrices. The synthesized Cu nanocomposite has been found to be more AC conducting at low frequency than Hg and Ag nanoparticles. The increasing increase in conductivity of membrane can be correlated due to the formation of localized electronic states in polymer matrix due to insertion of Cu nanoparticles.     

Preparation and properties of chitosan‐graft‐poly(methyl methacrylate) nanoparticles using potassium diperiodatocuprate (III) as an initiator

Graft copolymer nanoparticles prepared from chitosan (CS) and methyl methacrylate (MMA) monomer were synthesized in aqueous solution by using potassium diperiodatocuprate [Cu(III)] as an initiator and characterized in terms of particle size, zeta potential, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy, thermal stability, and X‐ray diffraction spectrometry. The results indicated that CS was covalently linked to poly(methyl methacrylate) (PMMA), and the resulting copolymers formed nanoparticles. These nanoparticles [prepared at 35°C, in a weight ratio of MMA/CS of 5 : 1 and with a Cu(III) concentration of 1.5 × 10⁻³ mol/L] were 54–350 nm in size, with a mean hydrodynamic diameter of 183 ± 3 nm and were highly uniform in particle‐size distribution, with a rather spherical shape and an obvious positive charge surface. The effect of reaction conditions such as Cu(III) concentration, reaction temperature, and the weight ratio of MMA/CS on the mean particle size was also investigated. Insulin‐loaded nanoparticles were prepared, and their maximal association efficiency was up to 85.41%. The experiment of release in vitro showed that the nanoparticles gave an initial burst release followed by a slowly sustained one. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011