Adsorption of BSA on carbon-coated Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> microspheres activated with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride

Carbon-coated Fe₃O₄ (Fe₃O₄/C) microspheres activated with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC) were prepared, characterized and applied to adsorb bovine serum albumin (BSA). The prepared magnetic microspheres had spherical core-shell structure with a uniform and continuous carbon coating coupled with activation by EDC, and possessed superparamagnetic characteristics. The experimental results showed that the adsorption amount of BSA on the EDC-activated Fe₃O₄/C (Fe₃O₄/C-EDC) microspheres was higher than that on the Fe₃O₄/C microspheres. The maximum adsorption of BSA on Fe₃O₄/C-EDC microspheres occurred at pH 4.7, which was the isoelectric point of BSA. At low concentrations (below 1.0 M), salt had no noticeable effect on BSA adsorption. The BSA adsorption of Fe₃O₄/C-EDC microspheres had a better fit to the Langmuir model than the Freundlich isotherm and Temkin isotherm model, and the kinetic data were well described by the pseudo-second-order model. The adsorption equilibrium could be reached within 20 min. High desorption efficiency (97.6%) of BSA from Fe₃O₄/C-EDC microspheres was obtained with 0.5 M Na₂HPO₄ (pH 9.4) as the desorbent.     

Effects of CFB Ash on the Adsorption Mechanism of Polycarboxylate Superplasticiser

The effects of circulating fluid bed(CFB) ash on the adsorption performance of polycarboxylate superplasticiser and the mechanism of this influence on the dispersive property of the polycarboxylate superplasticiser were investigated by determing the cement paste fluidity, total organic carbon adsorption, infrared spectroscopic analyses and ζ potential test. The experimental results show that the addition of an inorganic salt into the mixture to change the content of SO_4~(2-)and Fe_2 O_3 can improve the adaptability between the CFB ash and polycarboxylate superplasticiser. Adsorption may occur between the polycarboxylate superplasiciser and Fe_2 O_3, SO_4~(2-)or other components in CFB ash, leading to a significant reduction in paste fluidity. As the content of Na_2 SO_4 in CFB ash reaches 3% or Fe_2 O_3 reaches 9%, the paste loses its liquidity. The organic carbon content in the liquor decreases with an increase in Na2_ SO_4 or Fe_2 O_3 content. Adding some Ba(NO_3)_2 and Na_2 S to the liquor can recover the organic carbon content to a certain extent, and the absolute value of ζ potential will increase. The addition of Ba(-NO_3)_2 or Na_2 S reduces the adsorption property of Na_2 SO_4 or Fe_2 O_3 in CFB ash on the polycarboxylate superplasticiser.     

Characteristics of magnetic Fe3O4 nanoparticles encapsulated with human serum albumin

Magnetic nanoparticles （Fe304） were prepared by chemical precipitation method using Fe^2＋ and Fe^3＋ salts with sodium hydroxide in the nitrogen atmosphere. Fe3O4 nanoparticles were coated with human serum albumin（HSA） for magnetic resonance imaging as contrast agent. Characteristics of magnetic particles coated or uncoated were carried out using scanning electron microscopy and X-ray diffraction. Zeta potentials, package effects and distributions of colloid particles were measured to confirm the attachment of HSA on magnetic particles. Effects of Fe3O4 nanoparticles coated with HSA on magnetic resonance imaging were investigated with rats. The experimental results show that the adsorption of HSA on magnetic particles is very favorable to dispersing of magnetic Fe3O4 particles, while the sizes of Fe3O4 particles coated are related to the molar ratio of Fe3O4 to HSA. The diameters of the majority of particles coated are less than 100 nm. Fe3O4 nanoparticle coated with HSA has a good biocompatibility and low toxicity. This new contrast agent has some effects on the nuclear magnetic resonance imaging of liver and the lowest dosage is 20μmol/kg for the demands of diagnosis.     

Characteristics of activated carbon prepared from Chinese fir sawdust by zinc chloride activation under vacuum condition

The preparation of activated carbon from Chinese fir sawdust by zinc chloride activation under both nitrogen atmosphere and vacuum conditions was carried out in a self-manufactured vacuum pyrolysis reactor. The effects of the system pressure and the activation condition (nitrogen or vacuum) on pore development were investigated. The results show that both high quality activated carbon and high added-value bio-oil can be obtained simultaneously via vacuum chemical activation. The characteristics of the activated carbons produced under vacuum conditions are better than those prepared under nitrogen atmosphere. The performance parameters of the activated carbon obtained under vacuum conditions are as follows: the pore size distribution is mainly microporous, the Brunauer-Emmett-Teller (BET) surface area is 1 070.59 m²/g, the microporous volume is 0.502 4 cm³/g, the average pore size is 2.085 nm, and the iodine adsorption value and the methylene blue adsorption value are 1 142.92 and 131.34 mg/g, respectively. The activated carbon from vacuum chemical activation has developed micropores, and the N₂ adsorption equilibrium constant of the corresponding activated carbon gradually increases with the decrease of reaction system pressure.     

Synthesis and characterization of biomimetic Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>/coke magnetic nanoparticles composite material

A composite material (Fe₃O₄/Coke) using coke supported Fe₃O₄ magnetic nanoparticles was successfully prepared via an in-situ chemical oxidation precipitation method and characterized by SEM, XRD, Raman, and FTIR. The results showed that the Fe₃O₄ nanoparticles existed steadily on the surface of coke, with better dispersing and smaller particle size. The catalytic ability of Fe₃O₄/Coke were investigatied by degrading p-nitrophenol (P-NP). The results showed that the apparent rate constant for the P-NP at 1.0 g·L^?1 catalyst, 30 mmol·L^?1 H₂O₂, pH=3.0, 30 °C and the best ratio of Coke/Fe₃O₄ 0.6, was evaluated to be 0.027 min^–1, the removal rate of COD_Cr was 75.47%, and the dissolubility of Fe was 2.42 mg·L^–1. Compared with pure Fe₃O₄, the catalytic ability of Fe₃O₄/Coke in the presence of H₂O₂ was greatly enhanced. And Fe₃O₄/Coke was a green and environmental catalyst with high catalytic activity, showing a good chemical stability and reusability.     

Crystallization kinetics of amorphous Nd3.6 Pr5.4 Fe83Co3B5 and preparation of α-Fe/Nd2Fe14B nanocomposite magnets by controlled melt-solidification technique

The crystallization kinetics of amorphous Nd3. 6 Pr5.4 Fe83 Co3 B5 and the preparation of α-Fe/Nd2 Fe14 B nanocomposite magnets by controlled melt-solidification of Nd3.6Pr5.4Fe83Co3B5 was investigated by employing DTA, XRD, and TEM. The results show that a metastable intermediate phase Nd8Fe27B24 prior to α-Fe and Nd2 Fe14 B phases is crystallized as the amorphous Nd3.6 Pr5.4 Fe83 Co3 B5 is heated to 1 223 K. The crystallization activation energy of α-Fe and Nd8 Fe27324 phases is larger at the beginning stage of crystallization, and then it decreases with crystallized fraction x for the former and has little change when x is below 70% for the latter, which essentially results in an α-Fe/Nd2 Fe14 B microstructure with a relatively coarse grain size about 20-60 nm and a non-uniform distribution of grain size in the annealed alloy. The a-Fe/Nd2 Fe14 B nanocomposite magnets with a small average grain size about 14 nm and a quite uniform grain size distribution were prepared by controlled melt-solidification of nealing the amorphous Nd3. 6 Pr5. 4 Fe83 Co3 B5 precursor alloy.     

Catalytic hydrolysis of carbonyl sulfide over modified coal-based activated carbons by loading metal

A novel type of metal oxide/activated carbon catalyst was prepared by sol-gel method for the hydrolysis of carbonyl sulfide (COS). The influences of the calcination temperature, additive content (2.5%–10.0% Fe₂O₃, mass fraction) and the basic density of the activation process were thoroughly investigated. The surface of catalysts was characterized by Boehm titration. The products were characterized by scanning electron microscopy (SEM), X-ray diffractometry (XRD) and X-ray photoelectron spectroscopy (XPS). The results show that catalysts with 2.5%–5.0% Fe₂O₃ after calcining at 500 °C have superior activity. The conversion rate of COS increases with increasing the relative density of basic capacity loaded onto activated carbon(AC), and the activity follows the order: KOH>Na₂CO₃>NaHCO₃. Boehm titration data clearly show that the total acidity increases (from 0.06 to 0.48 mmol/g) and the basic groups decrease (from 0.78 to 0.56 mmol/g) after COS hydrolysis and H₂S adsorption. The XPS results show that the product of H₂S may be absorbed by the interaction with metal compounds and O₂ to form sulfate (171.28 eV) and element sulfur (164.44 eV), which lead to catalysts poisoning.     

Preparation and characterization of superparamagnetic Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>/CNTs nanocomposites dual-drug carrier

Fe₃O₄/carbon nanotubes (Fe₃O₄/CNTs) nanocomposites were prepared by polylol high-temperature decomposition of the precursor ferric chloride and CNTs in liquid triethylene glycol. After surface modification with hexanediamine, folate was covalently linked to the amine group of magnetic Fe₃O₄/CNTs nanocomposites. The products were characterized by Fourier-transform infrared spectroscopy, transmission electron microscopy, and vibrating sample magnetometry. Then Fe₃O₄/CNTs were used as a dual-drug carrier to co-delivery of the hydrophilic drug epirubicin hydrochloride and hydrophobic drug paclitaxel. The results indicated that the Fe₃O₄/CNTs had a favorable release property for epirubicin and paclitaxel, and thus had potential application in tumor-targeted combination chemotherapy.     

Preparation and properties of carbon fiber chiral materials

The chiral materials were prepared by using the carbon fiber helices as chiral inclusions, and the composite of Fe3O4 and polyaniline as matrix. The electromagnetic properties, including the rotation angles, the axial ratios and the complex chirality parameters, were measured by using a circular waveguide method in the 8.5-11.0 GHz frequency range. The dependence of these electromagnetic properties on the frequency and the concentration of the Fe3O4 in the composite matrix were analyzed. The results show that an appropriate concentration of Fe3O4 in the matrix is useful in improving the electromagnetic properties of the chiral material.     

污泥基催化剂强化臭氧深度处理煤制气废水中试性能

为解决煤制气废水生化处理后出水仍含有大量有毒和难降解污染物,对环境产生严重污染的问题,以污水污泥为原料制备污泥基活性炭,采用浸渍法将其负载过渡金属锰和铁的氧化物(主要为Mn_3O_4和Fe_3O_4,负载量分别为15.52%和7.45%),制备比表面积分别为327.5和339.1 m~2/g的臭氧催化剂.中试实验结果表明,催化剂的使用显著提高臭氧氧化废水污染物的效能,处理后出水COD、TOC、总酚和氨氮质量浓度分别为41~43,19~20,0.6~0.9和4.3~4.5 mg/L,均达到城镇污水处理厂污染物排放一级A标准;在最佳的臭氧投加量18 g/h条件下,催化剂的使用将臭氧利用率提高40%,达1.24 mg/mg(以COD计),显著降低工艺运行成本;相比新鲜的催化剂,连续50次的催化臭氧氧化运行,COD去除率仅下降5.2%.催化剂具有良好的稳定性,制备成本仅为5 000元/t.制备的臭氧催化剂具有性能高效稳定、经济节约和可持续发展的技术优势,适用于强化臭氧深度处理煤制气废水.     

Modification of Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> magnetic nanoparticles by L-dopa or dopamine as an enzyme support

Fe3O4 magnetic nanoparticles were prepared by co-precipitation of Fe^2＋ and Fe^3＋ in an ammonia solution, and its size was about 36 nm measured by an atomic force microscope. Fe3O4 magnetic nanoparticles were modified by L-dopa or dopamine using sonication method. The analysis of FTIR clearly indicated the formation of Fe-O-C bond. Direct immobilization of trypsin （EC： 3.4.21.4） on Fe3O4 magnetic nanoparticles with L-dopa and dopamine spacer was investigated using glutaraldehyde as a coupling agent. No significant changes in the size and magnetic property of the three kinds of magnetic nanoparticles linked with or without trypsin were observed. The existence of the spacer molecule on magnetic nanoparticles could greatly improve the activity and the storage stability of bound trypsin through increasing the flexibility of enzyme and changing the microenvironment on nanoparticles surface compared to the naked magnetic nanoparticles.     

Acid/base treatment of monolithic activated carbon for coating silver with tunable morphology

Silver coatings on the exterior surface of monolithic activated carbon (MAC) with different morphology were prepared by directly immersing MAC into [Ag(NH₃)₂]NO₃ solution. Acid and base treatments were employed to modify the surface oxygenic groups of MAC, respectively. The MACs’ Brunauer-Emmett-Teller (BET) surface area, surface groups, and silver coating morphology were characterized by N₂ adsorption, elemental analysis (EA), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM), respectively. The coating morphology was found to be closely related to the surface area and surface functional groups of MAC. For a raw MAC which contained a variety of oxygenic groups, HNO₃ treatment enhanced the relative amount of highly oxidized groups such as carboxyl and carbonates, which disfavored the deposition of silver particles. By contrast, NaOH treatment significantly improved the amount of carbonyl groups, which in turn improved the deposition amount of silver. Importantly, lamella silver was produced on raw MAC while NaOH treatment resulted in granular particles because of the capping effect of carbonyl groups. At appropriate [Ag(NH₃)₂]NO₃ concentrations, silver nanoparticles smaller than 100 nm were homogeneously dispersed on NaOH-treated MAC. The successful tuning of the size and morphology of silver coatings on MAC is promising for novel applications in air purification and for antibacterial or aesthetic purposes.     

Fabrication of Fe2O3@polypyrrole nanotubes and the catalytic properties under the ultrasound

Fe₂O₃@polypyrrole nanotubes (Fe₂O₃@PPy nanotubes) have been successfully prepared by in-situ polymerization of the pyrrole on the surface of Fe₂O₃ nanotubes (Fe₂O₃-NTs), via using L-Lysine as modified surfactant. Hollow PPy nanotubes were also produced by dissolution of the Fe₂O₃ core from the core/shell composite nanotubes with 1 mol·L^?1 HCl. Scanning electron microscopy(SEM), transmission electron microscope (TEM), selective-area electron diffraction (SAED), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy(FT-IR) confirmed the formation of Fe₂O₃-NTs and Fe₂O₃@PPy core/shell nanotubes. Its catalytic properties were investigated under the ultrasound. The results of UV-vis spectroscopy (UV) demonstrated Rhodamine B (RhB) can be efficiently degraded by Fe₂O₃ @PPy nanotubes.     

Synthesis of sodium beta alumina films by heat treatment of sodium aluminum oxides

Sodium beta alumina(Na-β-alumina) films were synthesized by heat treatment of NaAl_6O_(9.5)and γ-NaA1O_2 films at temperatures of 1 373-1 573 K.Single-phase γ-NaA1O_2 and NaAl_6O_(9.5) films were prepared by laser chemical vapor deposition at the deposition temperatures of 976 and 1 100 K,respectively.Subsequent heat treatment of the films resulted in the formation of Na-β-alumina with α-Al_2O_3 at temperatures above 1 373 K for NaAl_6O_(9.5) and 1 473 K for γ-NaA1O_2.On heat treatment at temperatures of 1 473-1 573 K,the faceted morphology with terraces of the as-deposited(110)-oriented γ-NaAlO_2 films transformed to a porous morphology with platelet grains comprising Na-β-alumina and α-Al_2O_3.On heat treatment at temperatures of1 373-1 473 K,the pyramidal,faceted grains of as-deposited NaAl_6O_(9.5) films transformed to planer,shapeanisotropic morphology in the film of mixed Na-β-alumina and α-Al_2O_3.A dense morphology was observed in both the as-deposited and heat-treated NaAl_6O_(9.5) films.     

An efficient chemical reduction-induced assembly of Fe3O4@graphene fiber for wire-shaped supercapacitors with ultrahigh volumetric energy density

Benefiting from high flexibility and weavability, the wire-shaped supercapacitors (SCs) arouse tremendous interests for the applications in wearable/portable electronics. Graphene fiber (GF) is considered as a promising linear electrode for wire-shaped SCs. However, the bottleneck is how to develop the GF-based linear electrode with facile fabrication process while well-maintaining satisfactory electrochemical performance. Herein, a novel Fe₃O₄@GF composite linear electrode is proposed via a chemical reduction-induced assembly approach, in which the GO and Fe₃O₄ nanoparticles (NPs) realize the efficient self-assembly owing to the electrostatic and van der Waals interactions, as well as the sufficient reduction of GO during the preparation process. The resultant fiber-shaped architecture shows boosted charge-transfer kinetics, high flexibility and structural integrity. Such Fe₃O₄@GF linear electrode exhibits excellent electrochemical behaviors including a large volumetric specific capacitance (∼250.75 F cm⁻³), remarkable rate capability and favorable electrochemical kinetics in aqueous electrolyte, superior than previously reported GF-based linear electrodes. For real application, a high-performance wire-shaped SC with excellent flexibility and weavability is fabricated based on such Fe₃O₄@GF linear electrode and gel electrolyte, demonstrating ultrahigh volumetric energy density (18.8 mWh cm⁻³), power density (4000 mW cm⁻³) and strong durability (∼93.5% retention after 10000 cycles). Prospectively, the fabricated wire-shaped SC can maintain reliable electrochemical behaviors in various deformation states, showing its potentials in future portable and wearable devices.

     

Fluorescence detection for H<Subscript>2</Subscript>PO<Subscript>4</Subscript><Superscript>-</Superscript> based on carbon dots/Fe<Superscript>3+</Superscript> composite

A novel fluorescent probe for H₂PO₄ ^- was designed and fabricated based on the carbon dots/Fe³⁺ composite. The carbon dots were synthesized by an established one-pot hydrothermal method and characterized by transmission electron microscope, X-ray diffractometer, UV-Vis absorption spectrometer and fluorescence spectrophotometer. The carbon dots/Fe³⁺ composite was obtained by aqueous mixing of carbon dots and FeCl₃, and its fluorescence property was characterized by fluorescence spectrophotometer. The fluorescence of carbon dots was quenched by aqueous Fe³⁺ cations, resulting in the low fluorescence intensity of the carbon dots/Fe³⁺ composite. On the other hand, H₂PO₄ ^- reduced the concentration of Fe³⁺ by chemical reaction and enhanced the fluorescence of the carbon dots/Fe³⁺ composite. The Stern-Volmer equation was introduced to describe the relation between the relative fluorescence intensity of the carbon dots/Fe³⁺ composite and the concentration of H₂PO₄ ^-, and a fine linearity (R ²=0.997) was found in the range of H₂PO₄ ^- concentration of 0.4-12 mM.     

Gap-plasmon of Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>@Ag core-shell nanostructures for highly enhanced fluorescence detection of Rhodamine B

A novel gap-plasmon of Fe₃O₄@Ag core-shell nanoparticles for surface enhanced fluorescence detection of Rhodamine B (RB) was developed. Fe₃O₄@Ag core-shell nanostructures with Ag shell and Fe₃O₄ core were synthetized by self-assembled method with the assistance of 3-mercaptopropyl trimethoxy silane (MPTS). To study the RB fluorescence enhanced by gap-plasmon, the fluorescence properties of RB on the substrates with different nanogap densities were systematically investigated, and the results showed that the fluorescence intensity of RB on Fe₃O₄@Ag core-shell NPs substrate was much stronger than that on bare glass substrate, and the fluorescence intensity was further improved by using multilayer Fe₃O₄@Ag core-shell NPs substrate which had higher nanogap density. Different from the mechanism that is based on the maximum overlap of the surface plasmon resonance (SPR) band and emission band, the mechanism of the fluorescence enhancement in our work is based on the localized surface plasmon (LSP) and the gap plasmon near-field coupling with the Fe₃O₄@Ag core-shell NPs. Besides, the detection limit obtained was as low as 1×10^-7 mol/L, and the Fe₃O₄@Ag core-shell NPs substrate had high selectivity for RB fluorophores. It was demonstrated that the Fe₃O₄@Ag core-shell NPs substrate had activity, good stability, and selectivity for fluorescence detection of RB. And the detection of RB by the surface plasmon enhanced fluorescence was more convenient and rapid than the traditional detection methods in previous works.     

Self-cleaning glass coated with Fe^3＋ -TiO2 thin film

The self-cleaning glass coated with Fe^3 -TiO2 photocatalytic thin film was prepared by sol-gel process from the system Ti(OC4H9),-NH(C2H4OH)2-C2H5OH-H2O containing FeCl3. The microstructure and properties of the film were studied using differential thermal analysis-thermogravimetry(DTA-TG), X-ray diffration (XRD) and scanning electron microscope(SEM). The transmittance of the self-cleaning glass was measured by using UV-Vis spectrometer. The effects of content of Fe^3 and the thickness of Fe^3 -TiO2 thin film on the photocatalytic ac-tivity were examined. The results show that the photocatalytic thin films are mainly composed of Fe3O4 and TiO2 particles within 10-100 nm. The appropriate amount of Fe^3 is effective for improving the photocatalytic activities of TiO2. The best photocatalytic activity is obtained when the molar ratio of Fe^3 to TiO2 is 0. 005 and the glass is coated with 9 layers.     

Assessment of pH-responsive nanoparticles performance on laboratory column flotation cell applying a real ore feed

Nanoparticles(NPs) can promote the column flotation process in mining industry. Nanoparticles' effects on column flotation process(copper recovery, grade and flotation rate constant) are assessed in Sarcheshmeh Copper Complex, Iran, through response surface methodology(RSM) optimization technique. The c-Al_2O_3, a-Fe_2O_3, SiO_2, and TiO_2 nanoparticles are selected for these experiments. A flotation rate constant is chosen as a response to assess the effect of nanoparticles on flotation in its kinetic sense.The process p H and nanoparticle dosage are selected as the influential parameters. Results obtained from RSM indicated that the maximum percentage of Cu recovery and grade is obtained at p H of 12 and nanoparticle dosage of 6 kg/t, through a-Fe_2O_3 and c-Al_2O_3 nanoparticles, respectively. Applying nanoparticles in particular c-Al_2O_3 and a-Fe_2O_3 increases the Cu recovery by 8–10% together with the grade by 3–6% in a significant manner. It is revealed that nanoparticles could effectively be applied in enhancing the flotation performance.     

Preparation of LiFePO4 for lithium ion battery using Fe2P2O7 as precursor

In order to obtain a new precursor for LiFePO4, Fe2P2O7 with high purity was prepared through solid phase reaction at 650 ℃ using starting materials of FeC2O4 and NH4H2PO4 in an argon atmosphere. Using the as-prepared Fe2P2O7, Li2CO3 and glucose as raw materials, pure LiFePO4 and LiFePO4/C composite materials were respectively synthesized by solid state reaction at 700 ℃ in an argon atmosphere. X-ray diffractometry and scanning electron microscopy（SEM） were employed to characterize the as-prepared Fe2P2O7, LiFePO4 and LiFePO4/C. The as-prepared Fe2P2O7 crystallizes in the Cl space group and belongs to β-Fe2P2O7 for crystal phase. The particle size distribution of Fe2P2O7 observed by SEM is 0.4-3.0 μm. During the Li^＋ ion chemical intercalation, radical P2O7^4- is disrupted into two PO4^3- ions in the presence of O^2-, thus providing a feasible technique to dispose this poor dissolvable pyrophosphate. LiFePO4/C composite exhibits initial charge and discharge capacities of 154 and 132 mA·h/g, respectively.