Tio2/SiO2/Fe3O4 magnetic nanoparticles synthesis and application in methyl orange UV photocatalytic removal

Three main parameters affecting TiO₂/SiO₂/Fe₃O₄ nanoparticles activity in photocatalytic degradation of methyl orange were investigated using response surface methodology (SRM). Precipitation method and sol-gel technique were used to prepare SiO₂/Fe₃O₄ electromagnetic composite support and TiO₂/SiO₂/Fe₃O₄ photocatalytically active nanoparticles. The specific surface area, pore volume, and average pore size of the synthesized nanoparticles were respectively equal to 56 m²/g, 0.12 cm³/g and 9.4 nm. The point of zero charge (PZC) of the catalyst was measured to be 5.9. The maximum and minimum photocatalytic degradation of methyl orange using the synthesized nanoparticles were 100% and 30%, respectively. A linear model was fitted to the obtained results with R²_adjusted equal to 0.87. The results of analysis of variance (ANOVA) revealed that catalyst concentration, reaction media pH and aeration rate were significantly affected the photocatalytic activity. Optimization was performed considering photocatalytic activity as the main objective functions. In order to maximize photocatalytic activity, catalyst loading, reaction media pH and aeration rate were respectively adjusted to 2,000 ppm, 3 and 2.5 L/min, which resulted in total methyl orange removal. Considering promising photocatalytic activity of TiO₂/SiO₂/Fe₃O₄ along with core-sell nanocomposite separation performance led us to propose this photocatalyst as an alternative solution for treating waste waters.

Glutathione detection in human serum using gold nanoparticle decorated, monodisperse porous silica microspheres in the magnetic form

A nanozyme for glutathione (GSH) detection in a broad concentration range was synthesized. GSH is usually detected up to an upper limit of 100 μM using current noble metal nanozymes due to the sharp decrease in the colorimetric response with the increasing GSH concentration. Strong inhibition of colorimetric reactions by GSH adsorbed onto noble metal based nanozymes in the form of non-porous, nanoscale particulate materials dispersed in an aqueous medium is the reason for the sharp decrease in the colorimetric response. In the present study, a new magnetic nanozyme synthesized by immobilization of Au nanoparticles (Au NPs) on magnetic, monodisperse porous silica microspheres (>5 μm) obtained by a "staged-shape templating sol-gel protocol" exhibited peroxidase-like activity up to a GSH concentration of 5000 μM. A more controlled linear decrease in the peroxidase-like activity with a lower slope with respect to that of similar nanozymes was observed with the increasing GSH concentration. The proposed design allowed the GSH detection in a broader concentration range depending on the adsorption of GSH onto the Au NPs immobilized on magnetic, monodisperse porous silica microspheres. A calibration plot allowing the detection of GSH in a broad concentration range up to 3300 μM was obtained using the magnetic nanozyme. The GSH concentration was also determined in human serum by elevating the upper detection range and adjusting the sensitivity of detection via controlling the nanozyme concentration.

Quaternary ammonium functionalized Fe3O4 & P(GMA-AA-DVB) magnetic Janus particles as highly efficient catalysts for phase transfer reactions

Magnetic Janus quaternary ammonium phase transfer catalysts possess excellent catalytic efficiency and are easy to recycle.

Amino-Fe3O4 Microspheres Directed Synthesis of a Series of Polyaniline Hierarchical Nanostructures with Different Wettability

We demonstrated polyaniline (PANI) dimensional transformation by adding trace amino-Fe3O4 microspheres to aniline polymerization. Different PANI nanostructures (i.e., flowers, tentacles, and nanofibers) could be produced by controlling the nucleation position and number on the surface of Fe3O4 microspheres, where hydrogen bonding were spontaneously formed between amino groups of Fe3O4 microspheres and aniline molecules. By additionally introducing an external magnetic field, PANI towers were obtained. These PANI nanostructures displayed distinctly different surface wettability in the range from hydrophobicity to hydrophilicity, which was ascribed to the synergistic effect of their dimension, hierarchy, and size. Therefore, the dimension and property of PANI nanostructures can be largely rationalized and predicted by adjusting the PANI nucleation and growth. Using PANI as a model system, the strategies presented here provide insight into the general scheme of dimension and structure control for other conducting polymers.

Well-Defined Peapod-like Magnetic Nanoparticles and Their Controlled Modification for Effective Imaging Guided Gene Therapy

Due to their unique properties, one-dimensional (1D) magnetic nanostructures are of great significance for biorelated applications. A facile and straightforward strategy to fabricate 1D magnetic structure with special shapes is highly desirable. In this work, well-defined peapod-like 1D magnetic nanoparticles (Fe3O4@SiO2, p-FS) are readily synthesized by a facile method without assistance of any templates, magnetic string or magnetic field. There are few reports on 1D gene carriers based on Fe3O4 nanoparticles. BUCT-PGEA (ethanolamine-functionalized poly(glycidyl methacrylate) is subsequently grafted from the surface of p-FS nanoparticles by atom transfer radical polymerization to construct highly efficient gene vectors (p-FS-PGEA) for effective biomedical applications. Peapod-like p-FS nanoparticles were proven to largely improve gene transfection performance compared with ordinary spherical Fe3O4@SiO2 nanoparticles (s-FS). External magnetic field was also utilized to further enhance the transfection efficiency. Moreover, the as-prepared p-FS-PGEA gene carriers could combine the magnetic characteristics of p-FS to well achieve noninvasive magnetic resonance imaging (MRI). We show here novel and multifunctional magnetic nanostructures fabricated for biomedical applications that realized efficient gene delivery and real-time imaging at the same time.

Ultrasmall superparamagnetic Ni nanoparticles embedded in polyaniline as a lightweight and thin microwave absorber

In this work, we have reported the preparation and lightweight and thin microwave absorbent application of ultrasmall Ni nanoparticles embedded in polyaniline (PANI).

Preparation of polyaniline (PANI)-coated Fe3O4 microsphere chains and PANI chain-like hollow spheres without using surfactants

Polyaniline (PANI)-coated Fe₃O₄ microspheres chains and PANI chain-like hollow spheres are successfully prepared without using surfactants.