Synthesis and performance of a cathode catalyst derived from areca nut husk in microbial fuel cell.

The role of the cathode catalyst is crucial in a single chamber Microbial Fuel Cell (MFC) to overcome the energy barrier. The present work aims todevelop a metal-free cathode catalyst from anagro-waste, areca nut husk and to evaluate its performance in MFC. Activated carbon with amorphous graphitic structure was synthesised at a pyrolysis temperature of 500 °C from the areca nut husk. The surface area of activated carbon is 1261.6 m2/g with an average particle size of 35.23 µm. The electrochemical characterisation of the cathode in oxygen saturated atmosphere reveals, a loading rate of 5 mg/cm2 possesses an equivalent conductivity to that of Pt catalyst. An Open Circuit voltage of 864 mV with a power density of 590 mW/m2 and a current density of 1.03517 A/m2 at 611.8 Ω was obtained. These results make the novel metal free catalyst a potential alternative to metal-based catalysts.

Evaluation of the Toxic Effect of Bauhinia purpurea Mediated Synthesized Silver Nanoparticles against In-vitro and In-vivo Models.

Metal nanoparticles, such as gold nanoparticles, silver nanoparticles, etc., have many benefits and have been in use for a very long time. Nevertheless, a number of concerns have been raised about the environmental impact and the possibility of exposure to various living systems at the moment. Thus, in this study, silver nanoparticles were synthesized by using plant gum from Bauhinia purpurea and characterization was done using UV-Visible Spectroscopy, Scanning Electron Microscopy, X-ray Diffraction, etc. To determine the accumulation and toxic effects caused by the nanoparticles, Eudrilus eugeniae, Danio rerio, and their embryos were exposed to the synthesized silver nanoparticles and evaluated using microscopic observation, histology, and Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES).

Surface-Engineered Super-Paramagnetic Iron Oxide Nanoparticles For Chromium Removal.

BACKGROUND: Super-paramagnetic iron oxide nanoparticles (SPIONs) are widely used metal nanoparticles for various applications for its magnetic property and biocompatibility. In recent years, pollution of our environment especially with heavy metals in waterbodies has become a major threat and has left us very minimal sources of freshwater to drink. SPIONs or surface modified SPIONs can be used to remove these heavy metals. METHODS: SPIONs were synthesized by co-precipitation method and further coated with a biopolymer, chitosan. Chromium solution was treated with the synthesized SPIONs to study the efficiency of chromium removal by surface adsorption. Later, the adsorption was analysed by direct and indirect analysis methods using UV-VIS spectrophotometry and isotherm studies. RESULTS: Stable chitosan-coated SPIONs were synthesized and they adsorbed chromium better than the uncoated SPIONs, where it was adsorbing up to 100 ppm. Adsorption was found to be increasing with decrease in pH. CONCLUSION: The surface-modified SPIONs expressed cumulative adsorption action. Even after the adsorption studies, chitosan-coated SPIONs were possessing magnetic property. Thus, the surface-modified SPIONs can become an ideal nanotechnology tool to remove the chromium from groundwater.

Surfactant-mediated synthesis of polyhydroxybutyrate (PHB) nanoparticles for sustained drug delivery.

In this study, polyhydroxybutyrate (PHB) nanoparticles were synthesised following nanoprecipitation method having different solvents and surfactant (Tween 80) concentrations. In this study, PHB nanoparticles were encapsulated with curcumin and subjected for sustained curcumin delivery. Both the curcumin loaded and unloaded PHB nanoparticles were characterised using FTIR, SEM, and AFM. Sizes of the particles were found to be between 60 and 300 nm. The drug encapsulation efficiency and in vitro drug release of the nanoparticles were analysed. Antibacterial activity and anticancer activity were also evaluated. The LC50 values of most of the nanoparticles were found to be between 10 and 20 µg/100 µl, anticancer activity of curcumin loaded PHB nanoparticles were further confirmed by AO/PI staining and mitochondrial depolarisation assay.