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Nano-composites comprised of magnetite nanoparticles in a pectin matrix were prepared by the co-precipitation method. Both sodium hydroxide and ammonium hydroxide were used as precipitating agents and the effects of stoichiometric ratios of iron salts to polymer concentration on particle properties were investigated. The precipitates obtained with NH 4 OH were sponge-like. The XRD pattern revealed magnetite as the only iron oxide phase present when NH 4 OH was used as precipitating base whilst nanoparticles precipitated using NaOH showed the presence of additional peaks. The nanocomposites obtained were further characterized using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray powder diffraction (XRD), and zeta-potential. FT-IR confirmed the COO-Fe linkage. Zeta-potential analysis showed a potential change from positive in pure magnetite to negative in polymer coated magnetite depending on the oxide-polymer ratio. SEM and TEM showed fairly evenly distributed nanosize pores.

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The presence of heavy metals released from industrial activities into water streams is an ever-growing challenge to ensuring a safe and clean aquatic environment. Detection and determination of the levels of these heavy metals in wastewater is an important step before any measures can be taken. In this study we report on a fluorescent sensing probe based on a naphthyl azo dye modified dibenzo-18-crown-6-ether (DB18C6) for the detection and determination of mercury (II) ions in water. The probe showed high sensitivity and selectivity towards the mercury (II) ion among various alkali, alkaline earth, and transition metal ions. The mercury (II) ion quenched the fluorescence of the probe. Stern-Volmer quenching constants (K sv ) were found to be highest for Hg 2+ ion at 1.18 x 10 5 M -1 compared to 3.85 x 10 4 M -1 for copper (II) ion. The stoichiometry of the sensormetal ion interaction was found to be 1:1 for both metal ions using Job plots. The detection limit for Hg 2+ was 1.25 x 10 -8 M. The dye modified crown ether was then used to detect mercury in a water sample from a coalfired power plant and to determine the amount of mercury in the water sample.

Bacterial infections are serious complications associated with wounds. Wounds can become chronic due to bacterial infections. In this research, lyophilized wound dressings were prepared from poloxamer, pluronic, mastic gum, and gum acacia. The wound dressings were loaded with metal‐based nanoparticles and carbon‐based materials. They exhibited effective antibacterial activity, water‐soluble, biodegradable with the capability to absorb large amounts of wound exudates. The bandages were analyzed using Fourier transform infrared spectroscopy, scanning electron microscopy/energy‐dispersive X‐ray spectroscopy, thermogravimetric analysis, and transmission electron microscopy followed by porosity and water uptake. TEM confirmed the successful incorporation of the metal‐based NPs and carbon‐based materials into the wound dressings. The TGA confirmed that the wound dressings are thermally stable. The wound dressings were also characterized by a high uptake of water to form a gel which was soluble in water indicating their useful application for wounds with large wound exudate, sensitive and damaged skin. The unique properties of the wound dressings indicate that they are potential materials for the treatment of chronic wounds in patients with sensitive skin. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48728.