Polishing performance of a magnetic nanoparticle-based nanoabrasive for superfinish optical surfaces.

Superfine optical components are necessary for advanced engineering applications such as x-ray optics, high-power lasers, lithography, synchrotron optics, laser-based sensors, etc. Fabrication of such superfine surfaces is one of the major challenges for optical and semiconductor industries. This research focuses on the development of a magnetic nanoparticle-based nanoabrasive for superfine optical polishing. The superparamagnetic iron oxide nanoparticle (SPION)-based nanoabrasive is synthesized via a hydrothermal route by employing cost-effective precursors. Detailed characterizations of the prepared nanoabrasive are presented. Transmission electron microscopy results confirm the irregular cubic and spherical shaped morphology of the SPION nanoabrasive along with particle size distribution varying from 10-60 nm, enabling the homogenous cutting effect of the aqueous slurry for polishing. Furthermore, the high surface area and pore size are determined by Brunauer-Emmet-Teller analysis and found to be 30.98m2/g and 6.13 nm, respectively, providing homogenous distribution of the nanoabrasive on the surface of a BK7 substrate for material removal. Application of the developed SPION abrasive is demonstrated for superfinish optical polishing on a BK7 optical disc. The experimental polishing results show superfine surface finishing with an average roughness value of 3.5 Å. The superparamagnetic property of the developed nanoabrasive is confirmed by alternative gradient magnetometry, and it helps in recovering the used nanoabrasive after polishing. Moreover, the polishing performance of the SPION nanoabrasives is compared with a cerium nanoabrasive, which is also synthesized in this study.

Development of highly efficient magnetically recyclable Cu2+/Cu0 nano-photocatalyst and its enhanced catalytic performance for the degradation of organic contaminations.

This work reports the successful functionalization of l-proline on the surface of superparamagnetic iron oxide nanoparticles (SPION) synthesized via a simple, cost-effective hydrothermal method. Moreover, the chemical attachment of Cu2+/Cu0 nanoparticles on the surface of SPION@l-proline was done by an in-situ deposition method. The developed nano-photocatalyst was characterized in detail by XRD, FT-IR, XPS, FE-SEM, TEM, EDX, BET, TGA, and VSM. XRD of SPION@l-proline-Cu reveals peaks of both SPION and copper nanoparticles which confirms the formation of nanophotocatalyst. TGA demonstrates a major weight loss between 250 and 310 °C due to l-proline which ensures the successful immobilization of SPION on the surface of l-proline. The band energy at 932 eV suggests a complete reduction of Cu2+ ion to Cu0 metal on the surface of SPION@l-proline nanocomposite as confirmed by the XPS technique. Under UV light irradiation, the photocatalytic reduction performance of the developed Cu2+ metal ion-based and Cu0 nanoparticle-based magnetic nano-photocatalysts was demonstrated and compared for the first time for the photocatalytic reduction of 4-NP, 4-NA, NB, MO, MB, and CR. The results show that Cu0-based magnetic nanophotocatalyst has slightly enhanced catalytic activity. Furthermore, solar-driven photocatalytic degradation of CR azo dye by synthesized nano-photocatalyst was also investigated, with a 95 % degradation efficiency in just 40 min. The developed magnetic nano-photocatalyst can easily be separated by using an external magnet due to the superparamagnetic nature of core material (SPION) at room temperature as confirmed from VSM and can be reused for multiple cycles without losing considerable catalytic activity. Because of its high photocatalytic efficiency, cost-effectiveness, good magnetic separation performance, non-toxicity, and strong thermal and chemical stabilities, Cu2+/Cu0-based magnetic nano-photocatalyst has potential application in wastewater treatment.

Bioinspired Nanocomposites: Applications in Disease Diagnosis and Treatment.

Recent advancement in the field of synthesis and application of nanomaterials provided holistic approach for both diagnosis as well as treatment of diseases. Briefly, three-dimensional scaffold and geometry of bioinspired nanocarriers modulate bulk properties of loaded drug at molecular/ atomic structures in a way to conjointly modulate pathological as well as altered metabolic states of diseases, in very predictable and desired manners at a specific site of the target. While, from the pharmacotechnical point of views, the bioinspired nanotechnology processes carriers either favor to enhance the solubility of poorly aqueous soluble drugs or enable well-controlled sustained release profiles, to reduce the frequency of drug regimen. Consequently, from biopharmaceutical point of view, these composite materials, not only minimize first pass metabolism but also significantly enhance in-vivo biodistribution, permeability, bio-adhesion and diffusivity. In lieu of the above arguments, the nano-processed materials exhibit an important role for diagnosis and treatments. In the diagnostic center, recent emergences and advancement in the tools and techniques to diagnose the unrevealed diseases with the help of instruments such as, computed tomography, magnetic resonance imaging etc; heavily depend upon nanotechnology-based materials. In this paper, a brief introduction and recent application of different types of nanomaterials in the field of tissue engineering, cancer treatment, ocular therapy, orthopedics, and wound healing as well as drug delivery system are thoroughly discussed.

Magnetically Recyclable Fe3O4@His@Cu Nanocatalyst for Degradation of Azo Dyes.

Fe3O4@His@Cu magnetic recyclable nanocatalyst (MRCs) was synthesized by reflux method using L-histidine as linker. The composition, structure and magnetic property of the product were characterized by X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), Fourier Transform infrared spectroscopy (FT-IR) and vibrating sample magnetometry (VSM). Powder XRD, FT-IR and EDAX results confirmed that the as-synthesized products has Fe3O4 with spinel structure and Cu nanoparticles with moderate crystallinity without any other impurities. The surface of the Fe3O4@His nanocomposite was covered by tiny Cu nanoparticles. We examine the catalytic activity of Fe3O4@His@Cu MRCs for the degradation of two azo dyes, methyl orange (MO) and methylene blue (MB) as well as their mixture. The reusability of the nanocatalyst was good and sustained even after 3 cycles. Therefore this innovated Fe3O4@His@Cu MRCs has a potential to be used for purification of waste water.