查找使用阿拉丁产品的科研文献

New insights on consolidation behavior of Fe2O3 in the Fe3O4-CaO-MgO-SiO2 system for fluxed pellet production: Phase transformations and morphology evolution

Shurong Shi,Lihua Gao,Junhong Zhang,Zhijun He

A systematic study of the preparation and metallurgical properties of magnesia flux pellets was used to elucidate the mechanism for oxidation and consolidation occurring during oxidative roasting. The compressive strength of the finished pellets was 3545 N/P. With sufficient basicity and MgO contents, magnetite (Fe) x [Fe] 2 O 4 and maghemite γ-Fe 2 O 3 with spinel-type crystal structures combined with MgO/CaO to form nonstoichiometric Mg x Fe 1-x Fe 2 O 4 (0 < x < 1) and Ca y Fe 1-y Fe 2 O 4 (0 < y < 1). With higher basicity and MgO contents, the participation of CaO/MgO was the driving force for gradient conversion from olivine Fe 2 SiO 4 to olivine Mg x Ca 2-x SiO 4 . The CaO/MgO combined with magnetite (Fe) x [Fe] 2 O 4 and maghemite γ-Fe 2 O 3 to form stable (Ca, Mg) x Fe 1-x Fe 2 O 4 , CaFe 2 O 4 and CaFe 3 O 5 , thereby inhibiting recrystallization of the pellets and resulting in poorer metallurgical properties of the magnesia flux pellets.

Catalytic ozonation of 2, 2′-methylenebis (4-methyl-6-tert-butylphenol) over nano-Fe3O4@cow dung ash composites: Optimization, toxicity, and degradation mechanisms

Cui Ma,Shengyong Jia,Pengfei Yuan,Zhengguang He

Composite magnetic oxide at cow dung ash, nano-Fe 3 O 4 @cow dung ash (nano-Fe 3 O 4 @CDA), was used as catalytic material for the degradation of 2, 2′-methylenebis (4-methyl-6-tert-butylphenol) (AO 2246) in real biologically pretreated landfill leachate . The Fe 3 O 4 @CDA composite exhibited catalytic ozonation activity and allowed material separation and magnetic recovery. The effects of several operating parameters including O 3 concentration, catalyst dosage, temperature and scavengers were evaluated in parallel. Over 70% of AO 2246 were removed by the nano-Fe 3 O 4 @CDA/O 3 system under optimum conditions within 120min reaction time. The EPR, GC–MS and free-radical quenching experiments expatiated the mechanism of this degradation process. It was confirmed that the AO 2246 was degraded efficiently in this catalytic micro-ozonation process, Additionally, GC–MS analysis state clearly that the 3,5-bis(1,1-dimethylethyl)phenol, 4-(1,5-dihydroxy-2,6,6-trimethylcyclohex-2-enyl)but-3-en-2-one, ethanone, 1-(1,4-dimethyl-3-cyclohexen-1-yl)-, 5-tert-butyl-6-3, 5-diene-2-one, 2-hydroxyhexanoic acid, 2-propenoic acid 1,1-dimethylethyl ester, butanoic acid, 2-methyl-, methyl ester and propanoic acid, 2, 2-dimethyl- were the dominant oxidation products (OPs) during the degradation of the AO 2246. The EPR results showed that the catalytic ozonation over Fe 3 O 4 @CDA led to produce more hydroxyl radicals , which were in favor of AO 2246 degradation. The toxicity evolution was also performed through a QSAR analysis calculated by the ECOSAR program which further demonstrated the different responses toward the AO 2246 and its OPs.

Biogenic synthesis of ferrous(III) oxide and Fe3O4/SiO2 using Chlorella sp. and its adsorption properties of water contaminated with copper(II) ions

Shireen Ibrahim Hamadamin,Sewgil Saaduldeen Anwer,Parween Mohsin Abdulkareem,Kwestan Hassan Sdiq

Magnetic Solid-Phase Extraction Based on Fe3O4/g-C3N4 Nanocomposite for the Determination of Polychlorinated Biphenyls and Polychlorinated Diphenyl Ethers in Environmental Waters

Ji Dongliang,Zhang Meixing,Geng Xinxiang,Zha Zhenxing,Li Ying,Yang Jing,Cui Shihai

The graphitic carbon nitride (g-C3N4) and the Fe3O4/g-C3N4 magnetic materials were synthesized in this paper. The structures of the materials were confirmed by a series of analysis. The Fe3O4/g-C3N4 was then used as a sorbent to adsorb polychlorinated diphenyl ethers and polychlorinated biphenyls. Different extraction conditions were examined, including adsorbent amount, salinity, pH of the sample matrix, adsorption time, reaction temperature, elution solvent and preconcentration factor. The maximum recoveries were obtained by employing methanol to desorb pollutants on 40.0 mg Fe3O4/g-C3N4 in 120.0 mL environmental water with a salinity of 5% (w/v) at a pH of 7 at 25 °C within 10 min. Using the optimized parameters, the detection limits of the method are between 0.01 and 0.04 μ · L−1 with a satisfying linear relationship. The adsorbent can be recycled at least 10 times with no significant reduction in the extraction efficiency.

Fabrication of Fe3O4 quantum dots modified BiOCl/BiVO4 p-n heterojunction to enhance photocatalytic activity for removing broad-spectrum antibiotics under visible light

Runren Jiang,Donghai Wu,Guanghua Lu,Zhenhua Yan,Jianchao Liu,Ranran Zhou,Matthew Nkoom

Herein, Fe 3 O 4 quantum dots modified BiOCl/BiVO 4 p-n heterojunction was successfully synthesized by a facile strategy. Multiple techniques were carried out to characterize the as-prepared samples. Results show that the photocatalysts possess regular crystal structure and consisted of BiOCl/BiVO 4 nanosheet structure with Fe 3 O 4 QDs on its surface. Particularly, 20% Fe 3 O 4 QDs@BiOCl/BiVO 4 p-n heterojunction shows universal outstanding photocatalytic activity for removing four different broad-spectrum antibiotics under visible light. Meanwhile, the mineralization degree and degradation pathways of antibiotic were further studied by 3D-EEMs and LC-MS/MS. The improved photocatalytic performance for degradation of broad-spectrum antibiotics mainly attributes to the effective charge carrier mobility, large specific surface areas, and strong visible light absorption. The photocatalytic reaction mechanism was also revealed by the electron spin resonance (ESR) technique and the active species trapping experiments. The photocatalyst stays stable crystal structures after four reaction cycles and it can be easily separated from the solution by an external magnetic field both demonstrate that the Fe 3 O 4 QDs@BiOCl/BiVO 4 p-n heterojunction has unlimited potential for practical usage. This work is expected to be widely applicable to the removal of broad-spectrum antibiotics.

An Ultrasensitive Electrochemical Immunosensor for HIV p24 Based on Fe3O4@SiO2 Nanomagnetic Probes and Nanogold Colloid-Labeled Enzyme–Antibody Copolymer as Signal Tag

Ning Gan,Xiaowen Du,Yuting Cao,Futao Hu,Tianhua Li,Qianli Jiang

An ultrasensitive portable electrochemical immunosensor for human immunodeficiency virus p24 (HIV p24) antigen detection has been developed, whereby the detection sensitivity was 1000 times higher than that of the ELISA method. Firstly, a novel HRP enzyme–antibody copolymer (EV-p24 Ab2) was synthesized through an EnVision regent (EV, a dextrin amine skeleton anchoring more than 100 molecules of HRP and 15 molecules of anti IgG), then incubated in the secondary antibody of p24. Secondly, the copolymer was immobilized on the gold nanocolloids (AuNPs) to fabricate a novel signal tag (AuNPs/EV-p24 Ab2). Subsequently, a sandwich-type immunoreaction would take place between the capture probe (silicon dioxide-coated magnetic Fe3O4nanoparticles (MNPs) labeled with the primary p24 antibody (MNPs-p24 Ab1)), p24 (different concentrations) and the signal tag [AuNPs/EV-p24 Ab2)] to form the immunocomplex. Finally, the immunocomplex was absorbed on the surface of screen printed carbon electrode (SPCE) by a magnet and immersed in the o-hydroxyl phenol (HQ) and H2O2. The large amounts of HRP on the signal tag can catalyze the oxidation of HQ by H2O2, which can induce an amplified reductive current. Moreover, the capture probe could improve the accumulation ability of p24 and facilitate its separation from the substrate through the magnet. Under optimal conditions, the proposed immunoassay exhibited good sensitivity to p24 within a certain concentration range from 0.001 to 10.00 ng/mL, with a detection limit of 0.5 pg/mL (S/N = 3). The proposed method can be used for real-time and early detection of HIV-infected people.

A yolk–shell Fe3O4@void@carbon nanochain as shuttle effect suppressive and volume-change accommodating sulfur host for long-life lithium–sulfur batteries

Ting Zhou,Zihan Shen,Yong Wu,Tianli Han,Mengfei Zhu,Xue Qiao,Yajun Zhu,Huigang Zhang,Jinyun Liu

A lithium–sulfur (Li–S) battery is considered a promising next-generation secondary battery owing to its high theoretical capacity and energy density. However, the volume change and poor conductivity of sulfur, and the shuttle effect, restrict its practical applications. Herein, we develop a yolk–shell Fe3O4@S@C nanochain as the Li–S battery cathode in which sulfur is encapsulated between the Fe3O4 core and the carbon shell. After cycling 500 times at 0.2C, the Fe3O4@S@C nanochains exhibit a stable capacity of 625 mA h g−1 and a coulombic efficiency exceeding 99.8%. When measuring at temperatures of −5 and 45 °C, the capacities remain stable, and a well-reversible rate performance under repeated testing for three rounds is also achieved. Furthermore, density functional theory (DFT) calculations show large adsorption energies of Fe3O4 towards polysulfides, indicating the capability of suppressing the shuttle effect during long-term charge and discharge.

Core-shell magnetic molecularly imprinted polymers based on Fe3O4@SiO2–C = C carrier for selective adsorption and rapid detection of ibuprofen in environment

Junxia Chai,Hongbo Mo,Chuan Wang,Fengjie He,Jufen Huang,Li Ran,Weigang Fan,Yuepeng Fan,Fan Lu

This study developed Fe3O4@SiO2–C = C-based magnetic molecularly imprinted polymers for selective ibuprofen removal and detection. The optimized synthesis using an ibuprofen (IBP)/(3-aminopropyl)triethoxysilane (APTES)/tetraethyl orthosilicate (TEOS) molar ratio of 1:6:18 achieved a high adsorption capacity of 68.18 mg·g−1 and an imprinting factor of 2.17. The adsorption process followed pseudo-second-order kinetics and the Freundlich isotherm model, indicating multilayer binding behavior. The material demonstrated excellent reusability with only 2.8% capacity loss after five cycles and good reproducibility with a relative standard deviation of 4.48%. In magnetic solid-phase extraction applications, the recovery rate reached 81.61% to 96.40% for real water samples with a detection limit of 0.09 μg·mL−1. The polymers showed selective recognition of ibuprofen over structural analogs due to synergistic π-π interactions and hydrogen bonding, thus offering an efficient strategy for remediating pharmaceutical pollutants in water.

Bioinspired silk fibroin/poly-acrylic acid high-performance hydrogel sensors with micro-architecture prepared by rapid polymerization via TA-Fe3O4@MXene catalytic system

Daen Qin,Chengyu Liu,Kaili Song,Seeram Ramakrishna

Hydrogels are ideal for flexible sensors due to their outstanding advantages such as softness, biocompatibility, and unique flexibility. However, the radical polymerization process of hydrogels is usually associated with intensive input of energy. In this study, tannic acid and Fe 3 O 4 nanoparticles were integrated on conductive MXene nanosheets as catalysts to rapidly polymerize to prepare super-stretchable and highly-sensitive Silk Fibroin/Poly-acrylic acid hydrogel sensors. The synergistic effect of TA and Fe 3 O 4 nanoparticles can maintain the dynamic redox cycling between Fe 2+ /Fe 3+ , to enhance the ability of ammonium persulfate to generate free radicals and rapidly forming hydrogel within 5 min. Inspired by the surface morphology of lotus leaves, a biomimetic strategy was employed to construct micro-protrusion structures on the hydrogel surface in order to enhance its sensitivity. The developed sensor showed excellent tensile strain (946 %) and high tensile strength (195 kPa), high sensitivity (GF = 4.05) and stable cycling ability (>100 cycles). The hydrogel sensor demonstrated high linearity (0.99 within the strain range of 150 %–600 %), low detection limit (1 % for strain and 150 Pa for pressure). Moreover, the hydrogel sensor can accurately detect various physiological signals emitted by the human body, making it highly promising for applications as wearable sensors in personalized healthcare.

A novel strategy for ultrasensitive detection and effective inactivation of Staphylococcus aureus based on Fe3O4-QCS-PEI-Cu-aptamer and ladder-branch HCR

Ren Dongxia,Wang Lin,Wei Hua,Mu Shijie,Yang Longfei

Bacterial infection is one of the leading causes of human death globally and is considered to be an urgent public health challenge. It is important to accurately and rapidly detect and kill pathogenic microorganisms. Therefore, a multifunctional platform for sensitive detection and efficient elimination of pathogenic bacteria should be developed to reduce the threat of bacteria. In this study, an integrated strategy based on Fe 3 O 4 -quaternary ammonium chitosan-polyetherimide-Cu-aptamer (Fe 3 O 4 -QCS-PEI-Cu-aptamer) and ladder-branch hybridization chain reaction (HCR) was proposed for the detection and inactivation of Staphylococcus aureus ( S. aureus ). The aptamer-complementary chain (aptamer-CP) conjugated to the surface of Fe 3 O 4 -QCS-PEI-Cu induces CP release in the presence of S. aureus , further initiating the ladder-branch HCR reaction and achieving signal amplification. Under optimal conditions, the developed sensor demonstrated a limit of detection (LOD) of 3 CFU/mL for S. aureus and exhibited high selectivity against several other pathogenic bacteria. Moreover, the Fe 3 O 4 -QCS-PEI-Cu-aptasensor showed potent antibacterial properties under near infrared (NIR) irradiation, achieving an antimicrobial efficiency of 99.946%. This strategy synergistically combined the high-sensitivity molecular detection with the antibacterial activity of novel nanomaterials activated by near infrared light, providing a new insight into the prevention of bacterial infections. Graphical

Intercalation Effect of Attapulgite in g-C3N4 Modified with Fe3O4 Quantum Dots To Enhance Photocatalytic Activity for Removing 2-Mercaptobenzothiazole under Visible Light

Zhi Zhu,Yang Yu,Hongjun Dong,Zhi Liu,Chunxiang Li,Pengwei Huo,Yongsheng Yan

A novel magnetic intercalation Fe3O4-QDs@g-C3N4/ATP photocatalyst was first prepared by a combined eutectic method with deposition technology; it shows superior degradation efficiency for removing 2-mercaptobenzothiazole (MBT) under visible light. The improved photocatalytic performance is mainly attributed to the intercalation effect of attapulgite (ATP) in g-C3N4 together with the quantum effect of Fe3O4 quantum dots (QDs) and the better conductivity between ATP and g-C3N4 resulting in the enhanced separation efficiency of photogenerated electron–hole pairs in the light absorption range. Moreover, insight into this mechanism indicates that the holes and superoxide radicals are the major active species in the MBT removal procedure. This work provides an efficient and promising approach to construct new high-performance g-C3N4-based photocatalytic materials for wastewater treatment.

Multi-walled carbon nanotubes modified with iron oxide and manganese dioxide (MWCNTs-Fe3O4−MnO2) as a novel adsorbent for the determination of BPA

Xiaojing Guo,Yejing Huang,Wanxiang Yu,Xiao Yu,Xiufen Han,Haiyun Zhai

Multi-walled carbon nanotubes modified with iron oxide and manganese dioxide (MWCNTs-Fe 3 O 4 −MnO 2 ) was synthesized by using iron oxide (magnetic agent) and manganese dioxide (surface enhancer agent) to further approach in a magnetic solid-phase extraction (MSPE) coupled with high performance liquid chromatography (HPLC) method for the determination of bisphenol A (BPA) in plastic bottled drink samples. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray (EDX), Fourier-transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM), and BET surface area measurement (BET) were used to characterized the materials. MWCNTs-Fe 3 O 4 MnO 2 are more effective for BPA adsorption than other materials which compared in this study. The binding performances of sorbent were evaluated by static and kinetic adsorption experiments. The data were well fitted to the Langmuir isotherm model and pseudo-second-order model, which the maximum adsorption capacity ( q max ) and the contact time of initial concentrations to achieve equilibrium were found to be 132.9 mg g −1 and 150 min, respectively. After adsorption, MWCNTs-Fe 3 O 4 −MnO 2 can be conveniently and quickly separated from the media by an external magnetic field, and adsorption-desorption capacity can remain at least 6 times of usage. Several parameters affecting the extraction efficiency were investigated. Under optimal conditions, the sorbent was successfully applied to MSPE followed by HPLC determination of BPA in real sample. The limit of detection (LOD) and limit of quantification (LOQ) values of MSPE-HPLC was 0.092 ng mL −1 and 0.167 ng mL −1 , respectively. Spiked recoveries ranged from 94.9 to 103.4% for four real samples, with relative standard deviations of less than 6.7%. It was concluded that the synthesized MWCNTs-Fe 3 O 4 −MnO 2 could be used as an efficient adsorbent for the determination of BPA in different plastic bottled drink samples.