Production of Carbon Nanofibers from Hibiscus Sabdariffa and Typha Latifolia for Photoreduction of Hexavalent Chromium Under Natural Sunlight

Abstract

Because of their low cost, chemical stability, and environmental friendliness, carbon nanofibers (CNFs) have a high potential for removing pollutants from water. CNFs with a large specific surface area are thought to be good candidates for pollutant removal. In this study, we demonstrate the direct thermal pyrolysis production of HS-CNFs and TL-CNFs from plant-based biomass obtained from Ambadi (Hibiscus Sabdariffa) and Cattail (Typha Latifolia). The biomass underwent thermal pyrolysis in a horizontal tube furnace at 900 °C for a duration of 2 hours. By utilizing a chemical activation method, the surface area of the synthesized CNFs was increased, resulting in graphitization. The surface area of CNFs derived from plant biomasses was measured to be 48.69 m2/g and 96.78 m2/g, respectively, for HS-CNFs and TL-CNFs. Owing to their high surface area and graphitic nature, the resulting CNFs were effectively employed to photoreduction of toxic Cr(VI) into less toxic Cr(III) in the presence of sunlight, using formic acid as a hole scavenger. The photoreduction of toxic Cr(VI) to less toxic Cr(III) took 60 minutes and 50 minutes, respectively, using biomass-derived HS-CNFs and TL-CNFs.

Keywords: Plant-based biomass, Hibiscus sabdariffa, Typha latifolia, metallic carbon nanofibers, photocatalyst, Cr(VI) reduction.