Removing Cd^(2+) by Composite Adsorbent Nano-Fe_3O_4/Bacterial Cellulose

A new composite adsorbent, nano-Fe3O4/bacterial cellulose（BC）, was prepared through blending method. The process of adsorbing Cd2＋ including its isotherm and kinetics measured was studied. The results show that the adsorption efficiency is improved because of huge surface area and surface coordination of nano-Fe3O4 particles. Its adsorption capacity is 27.97 mg/g and the maximum of Cd2＋ removal is 74%. The adsorption kinetics can be described by pseudo-second rate model and the adsorption equilibrium by Langmuir type. The superparamagnetism of nano-Fe3O4 particles can help to solve the difficult separation of single BC adsorbent and lead to the quick separation of composite adsorbent from the liquid if a magnetic field was applied. Cd2＋ can be desorbed effectively by EDTA and HCl from the composite adsorbent, which can make it be reused.

Preparation of Calcium Cross-linked Nano-Fe3O4 Modified Zeolite Microspheres for Cu^2+ Adsorption from Wastewater

Artificial zeolite was modified by nano-Fe3O4 for development of functional adsorbents.Subsequently,adsorbents such as calcium cross-linked nano-Fe3O4 microspheres (Ca-MS),calcium cross-linked nano-Fe3O4 modified zeolite microspheres (Ca-MZS) and iron cross-linked nano-Fe3O4 modified zeolite microspheres (Fe-MZS) were prepared and compared for their adsorption performance.The effects of adsorbent dosage,solution pH,initial concentration and ion content on the removal of Cu^2+ from wastewater are investigated,and the adsorption kinetics and isotherms for the adsorbent materials were analyzed.The experimental results indicate that for the initial concentration of Cu^2+ of 30 mg/L,the adsorption is noted to be most stable.The optimal initial pH for adsorbing Cu^2+ is observed to be 5.5.At an optimal dosage of Ca-MZS of 900 mg/L,the adsorption capacity is measured to be 28.25 mg/g,along with the removal rate of 72.49%.The addition of Na+ and K+ affects the adsorption of Cu^2+.For the Na^+ and K^+ concentration of 0.2 mmol/L,the Cu^2+ removal rate by Ca-MZS drops to 11.94% and 22.12%,respectively.As compared with the adsorbents such as Natural Zeolite (NZ),Ca-MS and Fe-MZS,Ca-MZS demonstrates the best removal effect in solution,where the removal rate reaches 84.27%,with the maximum adsorption capacity of 28.09 mg/g.The Cu^2+ adsorption kinetics of Ca-MZS is observed to follow the Elovich kinetic model,with the adsorption isotherm data fitting the Freundlich isotherm model by using the non-linear method.

Application of Polymerizable Surfactant in the Preparation of Polystyrene/Nano-Fe_3O_4 Composite

Monooctadecyl maleate, as a polymerizable surfactant, was synthesized by the mono-esterification of maleic anhydride and octadecanol, and was utilized to surface-modify nano-Fe3O4 particles. A polymerizable magnetic fluid was obtained by directly dispersing modified nano-Fe3O4 particles into styrene monomer, and the polystyrene/nano-Fe3O4 composite was prepared through free radical polymerization of polymerizable magnetic fluid. The structure and dispersion status in different dispersion phases of modified nano-Fe3O4 particles were studied by Fourier transform infrared （FTIR） spectrometry, X-ray diffraction （XRD） and transmission electron microscopy （TEM）, respectively. The experimental results show that the nano-Fe3O4 particles modified by monooctadecyl maleate with the size of about 7-10 nm can be uniformly dispersed into styrene and fixed in the composite during the procedure of polymerization. Thermogravimetric analysis （TGA） and vibrating sample magnetometry （VSM） indicate that the thermal stability of polystyrene/nano-Fe3O4 composite is improved compared to that of pure polystyrene, and the composite is a sort of superparamagnetic materials.

Photosynthetic Toxicity and Oxidative Damage Induced by nano-Fe3O4 on <i>Chlorella vulgaris</i>in Aquatic Environment

With the rapid development of nanotechnology and widespread use of nanoproducts, concerns have arisen regarding the ecotoxicity of these materials. In this paper, the photosynthetic toxicity and oxidative damage induced by nano Fe3O4 on a model organism, Chlorella vulgaris (C. vulgaris) in aquatic environment, were studied. The results showed that Nano-Fe3O4 was toxic to C. vulgaris and affected its content of chlorophyll a, malonaldehyde and glutathione, CO2 absorption, net photosynthetic rate, superoxide dismutase activity and inhibition of hydroxyl radical generation. At higher concentrations, compared with the control group, the toxicity of nano-Fe3O4 was significantly different. It suggested that nano-Fe3O4 is ecotoxic to C. vulgaris in aquatic environment.

Heterogeneous Degradation of Dyes in Industrial Effluent over Fenton-Like Nano-Fe₂O₃/Goldmine Complex

Nano-Fe2O3/goldmine complex was obtained by chemical coprecipitation reaction on the surface of goldmine waste-solid. Being used as the heterogeneous catalyst in Fenton-like advanced oxidation processes (AOPs), its treatment effect was studied in the removal performance of industrial dyes effluent. Although the maximal COD removal efficiency would reach 35.4% when 5 mL NaClO was added in 100 mL industrial dyes effluent, it is found that by using nano-Fe2O3/goldmine system, the COD removal efficiency of 13,000 mg/L dyes wastewater could reach up to 75.5% in the presence of 30 g/L nano-Fe2O3/goldmine complex and 50 mL/L NaClO at 50。C.

Dispersibility, Shape and Magnetic Properties of Nano-Fe₃O₄Particles

Nano-Fe3O4 particles were prepared by a two-step microemulsion method, the influence of molar ratio of water to NP-5 (R), alkali concentration and temperature on dispersibility and shape of the nanoparticles were discussed. Magnetic studies were also carried out using VSM in this paper. It was found that the optimum preparation parameters are R = 6.0, alkali concentration = 2.5 mol.L–1, initial total iron concentration as 0.88 mol.L–1, and the temperature being 30°C, the prepared nano magnetite particles have uniform size and good dispersibility with a crystal structure belonging to cubicFe3O4 and lattice parameters of a = 8.273 ?. The results of magnetic studies show, magnetic properties of particles are influenced by dispersibility of nanoparticles which depends on size of clusters. The better dispersibility of nanoparticles leads to more ordered inner magnetic vector, and so the stronger magnetic behavior of nano-Fe3O4 particles.

纳米Fe^0降解溶液中3,3′,4,4′-四氯联苯及其产物分析

采用振荡培养实验研究了纳米Fe0对溶液中3,3′,4,4′-四氯联苯(PCB77)的降解情况,结果表明,PCB77起始浓度为5mg/L、溶液初始pH值为6.8,反应64 h后,纳米Fe0投加量为10.0g/L时,PCB77残留浓度最低,残留率仅为29.3%;纳米Si0投加量为0.5g/L时,PCB77残留浓度最低,残留率为67%;纳米Si0投加量为1.0g/L,即纳米Si0:纳米Fe0=1∶10时,PCB77残留浓度最低,残留率仅为22.2%。溶液中PCB77降解产物中除联苯外未发现其他降解产物,可能是PCB77在纳米Fe0表面连续脱氯的原因造成的。

吡罗昔康在纳米Fe_3O_4-石墨烯复合修饰玻碳电极上的电化学行为及电分析研究

采用纳米Fe3 O4粒子（ nano-Fe3 O4）和石墨烯（ Reduced Graphene Oxide,RGO）制备了nano-Fe3 O4-RGO复合材料修饰玻碳电极（nano-Fe3O4-RGO/GCE）,采用循环伏安法（cyclic voltammetry,CV）,方波伏安法（square wave voltammetry,SWV）,计时电流法（ chronoamperometry,CA）,计时库仑法（ chronocoulometry,CC）研究了吡罗昔康（ Piroxicam,PC）在此复合修饰电极上的电化学行为及电化学动力学性质。实验结果表明,与GCE相比, nano-Fe3 O4-RGO/GCE对PC的电化学氧化作用有显著的促进作用,其氧化峰电流显著增加；对各种实验条件进行了优化,测得峰电流Ipa与PC浓度在2．0×10^-6～2．0×10^-4 mol·L^-1范围内呈良好的线性关系,检出限（S/N=3）为5．3×10^-7 mol·L^-1,加标回收率为100．0%～104．0%。该方法快速,灵敏,并将nano-Fe3O4-RGO/GCE用于市售吡罗昔康片剂的测定,结果符合定量测定要求。

纳米Fe_3O_4/离子液体电解质的制备及其性能研究

采用简单易制的1-丁基-3-甲基咪唑氯盐作为离子液体,纳米Fe_3O_4作为胶凝剂制备准固态电解质。用油酸钾对纳米Fe_3O_4进行改性,考察纳米Fe_3O_4改性前后、不同质量比纳米Fe_3O_4对准固态电解质的影响。利用X射线衍射仪、扫描电子显微镜、傅里叶红外光谱仪、电化学工作站等对样品进行表征。结果表明,纳米Fe_3O_4改性后导致准固态电解质的电导率下降,当纳米Fe_3O_4含量为4%时,电导率最高;当纳米Fe_3O_4含量为12%时,I_3^-在Pt电极上的还原速度最快。

Design and evaluation of glasphalt mixtures by using recycled waste cullet

A glass crusher was developed to improve the waste glass crushing process.The waste glass was recycled,crushed and sieved to different particle sizes as glass aggregates,and the surface of glass aggregates was treated by nano-Fe2O3 suspension to improve the anti-striping property.The glasphalt mixture made by partly replacing mineral aggregates with glass aggregates was designed and evaluated.The sizes of glass aggregates were selected to be 2.36 and 4.75 mm,and the optimum concentration of nano-Fe2O3 suspension was determined to be 10%.The optimum asphalt content(OAC)was determined by the Marshall method and the glass aggregate content.The influence of the glass aggregate content on the technical properties of glasphalt mixtures were analyzed by the rutting test,three-point bending test,freeze-thaw splitting test and skid resistance test.The results show that the optimal content of glass aggregates and OAC are recommended to be 15%and 4.4%,respectively.These environmentally-friendly glasphalt mixtures can solve the problem of environmental pollution caused by waste glass,as well as reducing the cost of pavement materials and construction.

拉贝洛尔在nano-Fe_3O_4-多壁碳纳米管复合修饰玻碳电极上的电催化氧化及电分析方法

目的:研究拉贝洛尔(labetalol,LBT)在nano-Fe3O4与多壁碳纳米管(Multi-walled carbon nanotubes,MWCNTs)复合修饰玻碳电极(nano-Fe3O4-MWCNTs/GCE)上的电化学行为及电化学动力学性质,建立LBT电化学定量测定方法。方法:循环伏安法(Cyclic Voltammetry,CV),计时电流法(Chronoamperometry,CA),方波伏安法(Square Wave Voltammetry,SWV)以及电化学交流阻抗谱(EIS)。结果:在nano-Fe3O4-MWCNTs/GCE上LBT发生了一受扩散控制的不可逆电化学氧化过程。考查了实验条件对LBT伏安行为的影响,测定了LBT在nano-Fe3O4-MWCNTs/GCE上的电极反应过程动力学参数。用SWV法测得LBT氧化峰电流与其浓度在1.0#10-5$1.0#10-3mol.L-1呈线性关系,检出限(S/N=3)为1.0#10-5mol.L-1。并用本方法对市售LBT片进行了电化学定量测定,RSD在0.4%～0.9%之间,加标回收率在99.70%～103.0%之间。结论:nano-Fe3O4-MWCNTs/GCE对LBT电化学氧化具有良好的催化作用,该方法可用于市售LBT片中LBT含量的电化学定量测定。

Catalytic oxidation of gas-phase elemental mercury by nano-Fe_2 O_3

Heterogeneous oxidation of gas-phase Hg 0 by nano-Fe 2 O 3 was investigated on a fixed bed reactor, and the effects of oxygen concentration, bed temperature, water vapour concentration and particle size have been discussed. The results showed that Hg 0 could be oxidized by active oxygen atom on the surface of nano-Fe 2 O 3 as well as lattice oxygen in nano-Fe 2 O 3 . Among the factors that affect Hg 0 oxidation by nano-Fe 2 O 3 , bed temperature plays an important role. More than 40% of total mercury was oxidized at 300°C, however, the test temperature at 400°C could cause sintering of nano-catalyst, which led to a lower efficiency of Hg 0 oxidation. The increase of oxygen concentration could promote mercury oxidation and led to higher Hg 0 oxidation efficiency. No obvious mercury oxidation was detected in the pure N 2 atmosphere, which indicates that oxygen is required in the gas stream for mercury oxidation. The presence of water vapour showed different effects on mercury oxidation depending on its concentration. The lower content of water vapour could promote mercury oxidation, while the higher content of water vapour inhibits mercury oxidation.

Direct Electrochemistry of Horseradish Peroxidase Embedded in Nano-Fe_3O_4 Matrix on Paraffin Impregnated Graphite Electrode and Its Electrochemical Catalysis for H_2O_2

Fe3O4 particles coated with acrylic copolymer (ACP) of about 5-8 nm in diameter were synthesized and used for immobilization of horseradish peroxidase (HRP). Direct electrochemistry of HRP embedded in the nanosized Fe3O4 solid matrix modified paraffin impregnated graphite electrode (PIGE) was achieved, which is related to the heme Fe(III)/Fe(II) conversion of HRP. Cyclic voltammetry gave a pah- of reproducible and well-defined redox peaks at about Em of -0.295 V vs. SCE. The standard rate constant k, was determined as 2.7 s-1. It demonstrated that the nano-Fe3O4 solid matrix offers a friendly platform to assemble the HRP protein molecules and enhance the electron transfer rate between the HRP and the electrode. UV-Vis absorption spectra and FTIR spectra studies revealed that the embedded HRP retained its native-like structure. The HRP/Fe3O4/PIGE showed a strong catalytic activity toward H2O2. The voltammetric response was a linear function of H2O2 concentration in the range of 10-140 μmol/L with detection limit of 7.3 μmol/L (s/n = 3). The apparent Michaelis-Menten constant is calculated to be 0.42 mmol/L.

分子印迹氨基功能化纳米Fe_3O_4高分子磁性复合材料的合成及其对海水中2,4,6-三氯苯酚的吸附性能

为了实现海水中2,4,6-三氯苯酚(2,4,6-TCP)的选择性吸附和去除,采用超声协助悬浮聚合法以2,4,6-三氯苯酚为模板制备了分子印迹氨基功能化纳米Fe3O4高分子磁性复合材料(nFe3O4@MIPNH2-polymer)。通过元素分析(EA)、X射线衍射(XRD)、傅里叶变换红外(FTIR)光谱分析、透射电子显微镜(TEM)、振动样品磁强计(VSM)等手段对nFe3O4@MIPNH2-polymer的组成、结构、形貌、磁性等进行表征,并研究了其应用于吸附和去除海水中2,4,6-三氯苯酚(2,4,6-TCP)污染物的性能。结果表明:合成的nFe3O4@MIPNH2-polymer平均粒径约为800nm,饱和磁化强度为32.6emu·g-1;水溶液中2,4,6-TCP的饱和吸附量为105.26mg·g-1,高于非分子印迹氨基功能化纳米Fe3O4高分子磁性复合材料(nFe3O4@NH2-polymer)的饱和吸附量(76.92mg·g-1),nFe3O4@MIPNH2-polymer对2,4,6-TCP的等温吸附线大体符合Langmuir模型。吸附热力学研究表明,nFe3O4@MIPNH2-polymer对2,4,6-TCP的吸附过程是自发的吸热熵增过程;吸附过程可在5min内达到平衡,动力学数据和准二级动力学模型符合较好;其吸附过程去除2,4,6-TCP的活化能为78.0kJ·mol-1。海水中的共存物质对吸附2,4,6-TCP几乎无干扰,nFe3O4@MIPNH2-polymer经洗脱后可以循环使用5次以上。nFe3O4@MIPNH2-polymer能高选择性地有效去除海水中的2,4,6-TCP。

纳米四氧化三铁对大鼠肠道内短链脂肪酸影响

目的探讨四氧化三铁纳米(nano-Fe_3O_4)颗粒对大鼠肠道内短链脂肪酸影响。方法 60只(雌雄各半)SD大鼠随机分为3组,分别为5%纤维素钠对照组、低、高剂量nano-Fe_3O_4组,每组20只,雌雄各半,每日灌胃给予不同剂量nano-Fe_3O_4,连续4周,每周以逼迫法采集新鲜粪便样品,采用气相色谱法测定大鼠肠道内的短链脂肪酸含量。结果染毒第4周时,与对照组比较,低、高剂量nano-Fe_3O_4组雌性大鼠肠道内丁酸含量[分别为(0.05±0.02)、(0.06±0.03)μg/μL]明显下降(P<0.05),低、高剂量nano-Fe_3O_4组雄性大鼠肠道内乙酸含量[分别为(1.31±0.16)、(1.54±0.22)μg/μL]明显下降(P<0.05),高剂量nano-Fe_3O_4组雄性大鼠肠道内丁酸含量[(0.04±0.02)μg/μL]下降,差异有统计学意义(P<0.05);染毒组大鼠部分肠上皮细胞出现空泡变性,杯状细胞排列疏松,柱状吸收细胞减少。结论此实验条件下nano-Fe_3O_4颗粒可能对大鼠肠道内短链脂肪酸含量产生影响。

Synthesis of boron nitride nanotube films with a nanoparticle catalyst

Boron nitride nanotube（BNNT） films were synthesized by combining ball milling and thermal chemical vapor deposition（CVD） using nano-Fe3O4 as a catalyst. The as-produced BNNTs have a bamboo-like structure and have a diameter in the range of 50~200 nm with an average length of more than 40 mm.Moreover, BNNT nanojunction structures were synthesized. The structure and morphology of the BNNTs were characterized by XRD, SEM, TEM and HRTEM. The possible growth mechanism of BNNTs and BNNT nanojunction structures were proposed. Though the BNNT films were observed, out of our expectation,BNNTs with thin tube wall and small average diameter have not been achieved, and this could be mainly ascribed to the aggregation of the nanoparticle catalyst, resulting in greater catalyst particles during the process of BNNT growth. This result will provide a promising approach to obtain the desired shape of BNNTs and produce branched junctions of BNNTs.