Nanostructured magnetite coated by natural product extracts to remove heavy metal ions and inactivate bacteria

The plant- magnetite interactive nanoparticles were synthesized via wet chemistry (coprecipitation) method and natural product extracts under controlled reaction conditions with optimized fabrication parameters. The plant-magnetite interactive nanoparticles were found to be efficient in the remediation of pollutants from the wastewater. In this research study, Aloe vera plant extracts were employed for the surface modification of the magnetite nanoparticles. The diastereoisomers Aloin A and Aloin B, a major component in Aloe vera plant extract, were found to be the active coating material on the nanoparticles. The Aloin A and Aloin B mixture were able to effectively control particle growth and maintained the crystal structure of the nanoparticles. They prevented the aggregation of the nanoparticles through steric hindrance. The coating material, Aloin A and Aloin B mixture possess hydroxyl (-OH) functional groups which increased the adsorption efficiency of the nanoparticles. The synthesized plant-magnetite interactive nanoparticles were found to have a spinel structure with a spherical shape. The result obtained from the optical density readings showed that plant-magnetite nanoparticles were efficient in the remediation of a heterogeneous mixture of mercury (Hg2+) ions and Escherichia coli (E. coli). The inactivation of E. coli cells increased with the increasing concentration of Hg2+ions absorbed by the nanoparticles and prolonged time. Cell inactivation increased by 20 % from 5 to 100 parts-per-million (ppm) of Hg2+ ions adsorbed by the nanoparticles and this increase was steady over time. Besides, cell inactivation increased by 29 % with the use of Hg2+ adsorbed plant-magnetite interactive nanoparticles as opposed to bare plant magnetite interactive nanoparticles after 24 h. This shows that the toxicity of Hg2+ ions, which is as a result of its adsorption on the surface of the nanoparticles, increased the antibacterial efficiency of the nanoparticles