Research

An ultrasound assisted method for synthesis of magnetic Fe3O4/ɑ-MnO2 nanocomposite has been investigated. The synthesized Fe3O4/ɑ-MnO2 nanocomposite was characterized by X-ray Diffraction, UV-Vis spectroscopy, Scanning Electron Microscopy, Transmission Electron Microscopy and Energy Dispersive X-ray analysis. The photocatalytic property of the nanocomposite was tested by analyzing degradation of crystal violet in the presence of solar and UV-Vis irradiation. The optimum conditions for the photocatalytic process were determined. Fe3O4/ɑ-MnO2 nanocomposite photocatalyst was easily recovered through magnetic separation. The reusability of the catalyst was also explored. The results demonstrated ~100% photocatalytic degradation of crystal violet dye under solar irradiation and UV-visible irradiation within 70 min and 50 min respectively at pH 9. The experimental data fitted well with Lagergren’s first order reaction.

Lead (Pb) ions are a major concern to the environment and human health as they are contemplated cumulative poisons. In this study, facile synthesis of magnetic iron oxide–tea waste nanocomposite is reported for adsorptive removal of lead ions from aqueous solutions and easy magnetic separation of the adsorbent afterwards. About 95% Pb(II) ion removal is achieved with the magnetic tea waste within 10 min. A coefficient of regression R 2 ≃ 0.99 and adsorption density of 18.83 mg g−1 was found when Pb(II) ions were removed from aqueous solution using magnetic tea waste. The removal of Pb(II) ions follows the pseudo-second-order rate kinetics. External mass transfer principally regulates the rate-limiting phenomena of adsorption of Pb(II) ions on iron oxide–tea waste surface. The results strongly imply that magnetic tea waste has promising potential as an economic and excellent adsorbent for the removal of Pb(II) from water. 

The nano-particles of hematite (alpha-Fe2O3) has so many different properties like magnetism, hydrophilic, non-toxic, high chemical stability, chemical and biological compatibility and high potential in applications of environmental remediation. In this paper, we report the simple, promising, improved synthesis of hematite/alginate nanocomposites and characterized by XRD, SEM, FTIR and UV–visible. Hematite/alginate (AG) beads of diameter 2–3 mm were prepared and used for adsorption/removal of organic dyes like methylene blue. The removal of the 25 ppm MB dye was obtained ~100% within 40 min at pH 9 using 1 g/L hematite/AG beads nanocomposite at room temperature.