Incorporation of urea and cobalt nanoparticles into electrospun biocompatible PVP seed coats leads to controlled release of ammonia.

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This study discusses about the biosorption of Cr(VI) ion from aqueous solution using ultrasonic assisted (UASP). The prepared UASP biosorbent was characterised by Fourier transform infrared spectroscopy, X-ray diffraction, Brunauer-Emmet-Teller, scanning electron spectroscopy and energy dispersive X-ray and thermogravimetric analyses. The optimum condition for the maximum removal of Cr(VI) ions for an initial concentration of 50 mg/l by UASP was measured as: adsorbent dose of 1 g/l, pH of 3.0, contact time of 30 min and temperature of 303 K. Adsorption isotherm, kinetics and thermodynamic parameters were calculated. Freundlich model provided the best results for the removal of Cr(VI) ions by UASP. The adsorption kinetics of Cr(VI) ions onto UASP showed that the pseudo-first-order model was well in line with the experimental data. In the thermodynamic study, the parameters like Gibb's free energy, enthalpy and entropy changes were evaluated. This result explains that the adsorption of Cr(VI) ions onto the UASP was exothermic and spontaneous in nature. Desorption of the biosorbent was done using different desorbing agents in which NaOH gave the best result. The prepared material showed higher affinity for the removal of Cr(VI) ions and this may be an alternative material to the existing commercial adsorbents.

The synthesis of metal nanoparticles (NPs) loaded on the ultrasonic-assisted Spirulina platensis (MNPs/UASP) was investigated using the green synthesis method. The S. platensis algal extract was taken as a reducing agent. The formations of metal NPs were characterised using UV-visible spectroscopy, Fourier transform infrared spectroscopy and scanning electron microscopy. The antimicrobial activity of different metal NPs demonstrated various inhibitory activities against one gram-positive bacteria (Staphylocicus aureus), four gram-negative bacteria (Klebsiella pneumonia, Proteus vulgaris, Pseudomonas aeruginosa and Escherichia coli) and one fungus (Aspergillus niger). Both CrNPs/UASP and ZnNPs/UASP show good antimicrobial activity when compared with other MNPs/UASP against microorganisms. This MNPs/UASP is effective in preventing and treating the microbial infection and water pollution in the environment.