Synthesis and characterization of Cu@Cu2O core shell nanoparticles prepared in seaweed Kappaphycus alvarezii media

This study reports a synthesis of Cu@Cu2O core shell nanoparticles (NPs) in Kappaphycus alvarezii (K. alvarezii) media via a chemical reduction method. The nanoparticles were synthesis in an aqueous solution in presence of K. alvarezii as stabilizer and CuSO4.5H2O precursor. The synthesis proceeded with addition of NaOH as pH moderator, ascorbic acid as antioxidant and hydrazinium hydroxide as the reducing agent. The resulting nanoparticles characterized by using UV–vis spectrum, X-ray diffraction, Transmission electron microscopy, Fourier transform infrared (FT-IR) and atomic force absorption (AFM). The UV-visible spectra indicate to peaks at 590 nm and 390 which confirmed the formation of Cu@Cu2O-NPs. The XRD used in analysis of the crystal structure of nanoparticles. The morphology and structure of the K. alvarezii/Cu@Cu2O-NPs were investigated by TEM and AFM. The average size of Cu@Cu2O-NPs obtained were around 53nm that confirmed by using X-ray diffraction, TEM and AFM. The Fourier transform infrared FT-IR)spectrum suggested the complexation present between K. alvarezii and Cu@Cu2O-NPs

Effect of seaweed Kappaphycus alvarezii in the synthesis of Cu@Cu2O core–shell nanoparticles prepared by chemical reduction method

This study aims is to investigate the influence of different concentrations of Kappaphycus alvarezii (K. alvarezii) for the synthesis of Cu@Cu2O core–shell nanoparticles (NPs) in aqueous solution. The core–shell NPs were prepared by a chemical reduction method using K. alvarezii, CuSO4·5H2O, NaOH, ascorbic acid, hydrazinium hydroxide, as stabilizer, copper precursor, pH moderator, antioxidant and reducing agent under 120°C temperature, respectively. Formation of Cu@Cu2O-NPs was determined by UV–Vis spectroscopy where surface plasmon absorption maxima can be observed at 390-590 nm. The synthesized core–shell NPs were also characterized by X-ray diffraction. Moreover, the morphology and structure of the K. alvarezii/Cu@Cu2O-NPs were investigated by TEM, FESEM and EDXRF. The Fourier transform infrared spectrum suggested the complexation present between K. alvarezii and Cu@Cu2O-NPs. The study clearly showed that using various amounts of K. alvarezii leads to produce different ratios and sizes of Cu@Cu2O NPs. The size of the Cu@Cu2O-NPs decreased as the amount of K. alvarezii was increased. The ratio of Cu@Cu2O increases with the increasing concentration of K. alvarezii until 0.2 wt%

Preparation and characterization of core-shell copper nanoparticles stabilized by kappa carragenan and sodium alginate

Among metal nanoparticles, copper nanoparticles (Cu-NPs) have recently attracted increased attention because of their low cost (in contrast to Au and Ag) and their usable properties. Rate of resistance of microorganisms to antibiotics is alarming. Pathogenic bacteria are becoming much resistant to antibiotics. Copper nanoparticles synthesis particularly in bio-based stabilizers can act as antimicrobial agents, which in turn could resist pathogenic microorganisms. In this work, synthesis and characterization of Cu-NPs and Cu@Cu2O core shell nanoparticles (CSNPs) were carried out in the presence of two different marine polymers as stabilizers Kappaphycus alvarezii (K. alvarezii) and sodium alginate (SA) by two varied methods;chemical reduction and gamma irradiation. The aim of this research is to synthesize, characterize and test the antimicrobial activity of Cu and Cu2O nanoparticles. The Cu@Cu2O-CSNPs were synthesized by using chemical reduction method in K. alvarezii media. Also Cu-NPs and Cu@Cu2O -CSNPs were prepared in sodium alginate by using same method. The synthesis carried out using aqueous medium in presence of hydrazinium hydroxide as reducing agent, CuSO4.5H2O as copper precursor and sodium hydroxide as pH moderator. The effects of the concentration of K. alvarezii and sodium alginate as stabilizer were studied. Formation of nanoparticles was determined by UV–vis spectroscopy where surface plasmon absorption maxima can be observed at 390-600 nm from the UV–vis spectrum. The synthesized nanostructures were also characterized by X-ray diffraction (XRD). In addition; the morphology and structure of the nanoparticles were investigated by Transmission Electron Microscopy (TEM), emission scanning electron microscopy (FESEM) and Energy-dispersive X-ray spectroscopy (EDX). TEM results showed a gradual decrease of particle size from low concentration of K. alvarezii and sodium alginate to high concentration. The study clearly showed that using various amounts of K. alvarezii and sodium alginate led to produce Cu@Cu2O-CSNPs with different sizes and ratios of Cu:Cu2O. For the K. alvarezii/Cu@Cu2O-CSNPs, the Cu-NPs increased and the Cu2O decreased with increasing the concentration of K. alvarezii until 0.2 wt.% in the Cu@Cu2O-CSNPs. At the highest concentration of K. alvarezii, Cu decreased compare to Cu2O. Moreover for the Cu@Cu2O-CSNPs synthesized in sodium alginate with increasing the media concentration, the Cu increased and at the highest concentration of media (1.0 wt.%) only copper nanoparticles were produced. The size of the nanoparticles decreased as the amount of K. alvarezii and sodium alginate was increased. Moreover the K. alvarezii/Cu@Cu2O-CSNPs and SA/Cu-NPs were synthesized by using gamma irradiation method. The synthesis was done through γ-irradiation reduction of copper ions. The suspension was irradiated under γ-irradiation source 60Co with doses of 5, 20, 40, 80, 100 and 120 kGy at room temperature. The effect of irradiation dosage was investigated. The UV-Vis spectroscopy results obtained for samples indicated that only the samples which were irradiated by 80, 100 and 120 kGy showed surface plasmon resonance (SPR) peaks in the range of 350-600 nm. It was due to the formation of K. alvarezii/Cu@Cu2O-CSNPs and SA/Cu-NPs for these doses. TEM analysis indicated size and distribution of the nanoparticles varied in different doses of gamma irradiation. When the absorbed dose increased from 80 to 120 kGy the nanoparticle size decreased. Following synthesis of the nanoparticles, antibacterial analysis of the synthesized particles was investigated. Antimicrobial analysis conducted on the synthesized nanoparticles showed activity against all tested microorganisms

Size-controlled synthesis of Fe3O4 magnetic nanoparticles in the layers of montmorillonite

Iron oxide nanoparticles (Fe3O4-NPs) were synthesized using chemical coprecipitation method. Fe3O4-NPs are located in interlamellar space and external surfaces of montmorillonite (MMT) as a solid supported at room temperature. The size of magnetite nanoparticles could be controlled by varying the amount of NaOH as reducing agent in the medium. The interlamellar space changed from 1.24 nm to 2.85 nm and average diameter of Fe3O4 nanoparticles was from 12.88 nm to 8.24 nm. The synthesized nanoparticles were characterized using some instruments such as transmission electron microscopy, powder X-ray diffraction, energy dispersive X-ray spectroscopy, field emission scanning electron microscopy, vibrating sample magnetometer, and Fourier transform infrared spectroscopy