Oil Column Method for Magnetic Microspheres with Core-Shell Structure

2013 ◽  
Vol 743-744 ◽  
pp. 677-680
Author(s):  
Lian Qing Yu ◽  
Kai Tuo Dong ◽  
Qian Qian Zhi ◽  
Ming Jiang Cai
Keyword(s):  
Surface Area ◽  
Shell Structure ◽  
Magnetic Core ◽  
Magnetic Microspheres ◽  
Core Shell ◽  
Average Pore ◽  
Physical Strength ◽  
Catalyst Carrier ◽  
Shaping Time ◽  
Core Shell Structure

Spherical alumina catalysts have been widely used in fluidized bed and slurry-bed or catalyst carrier due to their excellent pore structure, large surface area, good physical strength and resistance to acids and stability. Magnetic microspheres of γ-Fe2O3 @ Al2O3 with core-shell structure were obtained by γ-Fe2O3 magnetic core coating with aluminum sol. After aging, drying and calcinations process, microspheres with certain hardness and magnetic properties can be obtained. During the preparation of core-shell structure microspheres, effect of both the content of aluminum sol, hexamethylenetetramine(HMT), magnetic core γ-Fe2O3 and process parameters of shaping time, aging temperature, calcination temperature on the properties of the spherical carrier was investigated. The optimum properties of microsphere carrier for hardness of 36.32 N/mm, specific surface area of 89.016 m2/g, pore volume of 0.874 cm3/g and average pore diameter 18.51 nm were synthesized, respectively.

Preparation, Characterization and Visible-Light Catalytic Activity of Core-Shell Structure NiFe2O4@TiO2 Ferrite Nanoparticles

2016 ◽  
Vol 680 ◽  
pp. 272-277
Author(s):  
Zhou Li Lu ◽  
Peng Zhao Gao ◽  
Rui Xue Ma ◽  
Yu Kun Sun ◽  
Dong Yun Li
Keyword(s):  
Catalytic Activity ◽  
Visible Light ◽  
Shell Structure ◽  
Shell Thickness ◽  
Spinel Ferrite ◽  
Sol Gel ◽  
Magnetic Core ◽  
Core Shell ◽  
Calcination Temperatures ◽  
Core Shell Structure

The core-shell structure NiFe2O4@TiO2 nanoparticles was successfully prepared using a sol-gel method, the influence of shell thickness and calcination temperatures on the composition, microstructure, magnetic properties and visible-light catalytic activity of the nanoparticles was studied by XRD, TEM, Uv–vis, vibrating sample magnetometer, etc. Results showed the main composition of core in NiFe2O4@TiO2 was spinel ferrite, and the shell was anatase TiO2, and theshell thickness increased significantly with the increase of TiO2 content, ranging from 10nm to 50nm. The Ms and Mr of nanoparticles decreased with the increase of TiO2 content, and no obvious reaction between the magnetic core and shell occurred; visible-light degradation percent of NiFe2O4@TiO2 nanoparticles increased along with the increase of TiO2 content, whereas the recovery rate of it decreased. Degradation percent and the recovery percent of NiFe2O4@TiO2-50 still reached 93.7% and 90.5%, even after 10 cycle times, respectively, possessing the excellent long-term stability.

scholarly journals A low-cost cementite (Fe3C) nanocrystal@N-doped graphitic carbon electrocatalyst for efficient oxygen reduction

2015 ◽  
Vol 17 (41) ◽  
pp. 27527-27533 ◽  
Author(s):  
Tianxing Wu ◽  
Haimin Zhang ◽  
Xian Zhang ◽  
Yunxia Zhang ◽  
Huijun Zhao ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Surface Area ◽  
Shell Structure ◽  
Low Cost ◽  
Reduction Reaction ◽  
Graphitic Carbon ◽  
Large Surface Area ◽  
Core Shell ◽  
Core Shell Structure

A core–shell structure Fe3C nanocrystal@N-doped graphitic carbon (Fe3C@NGC) nanocomposite was successfully fabricated, and used as an electrocatalyst with large surface area, exhibiting great potential for oxygen reduction reaction (ORR).

scholarly journals PEGylated Thermo-Sensitive Bionic Magnetic Core-Shell Structure Molecularly Imprinted Polymers Based on Halloysite Nanotubes for Specific Adsorption and Separation of Bovine Serum Albumin

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 536 ◽  
Author(s):  
Xiufang Li ◽  
Hui Liu ◽  
Zhiwei Deng ◽  
Wenqing Chen ◽  
Tianhao Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Bovine Serum Albumin ◽  
Adsorption Capacity ◽  
Molecularly Imprinted Polymers ◽  
Shell Structure ◽  
Magnetic Core ◽  
Core Shell ◽  
Molecularly Imprinted ◽  
Imprinted Polymers ◽  
Core Shell Structure

Novel PEGylated thermo-sensitive bionic magnetic core-shell structure molecularly imprinted polymers (PMMIPs) for the specific adsorption and separation of bovine serum albumin (BSA) were obtained via a surface-imprinting technique. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), fourier transform infrared spectrometry (FT-IR), thermal gravimetric analysis (TGA), and specific surface area (BET), were adopted to demonstrate that novel PMMIPs were successfully synthesized. Subsequently, the prepared PMMIPs were used as the extractor for BSA and were combined with magnetic solid-phase extraction. The concentrations of BSA were detected by UV-vis spectrophotometry at 278 nm. The maximum adsorption capacity of the PMMIPs was 258 mg g−1, which is much higher than that of non-imprinted polymer (PMNIPs). PMMIPs showed favorable selectivity for BSA against reference proteins, i.e., bovine hemoglobin, ovalbumin and lysozyme. PMMIPs were further used to recognize BSA in protein mixtures, milk, urine and sewage, these results revealed that approximately 96% of the ideal-state adsorption capacity of PMMIPs for BSA was achieved under complicated conditions. Regeneration and reusability studies demonstrated that adsorption capacity loss of the PMMIPs was not obvious after recycling for four times. Facile synthesis, excellent adsorption property and efficient selectivity for BSA trapping are features that highlight PMMIPs as an attractive candidate for biomacromolecular purification.

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