Fabrication and characterization of novel Fe⁰@Guar gum-crosslinked-soya lecithin nanocomposite hydrogel for photocatalytic degradation of methyl violet dye

Water pollution is the most threatening issue prevailing in our society these days. Methyl violet is released into the water resources through textile and paint industries. High dye concentration in water inhibits the photosynthesis process thus, affecting the aquatic life. In addition, it indirectly affects the human health also. So for photochemical exclusion of methyl violet from aqueous solution, we have designed zero valent iron @guar gum crosslinked soya lecithin nanocomposite hydrogel (Fe⁰@GG-cl-SY NCH), synthesized via ultrasonication method. Impregnation of zero valent iron (ZVI) onto the GG-cl-SY was characterized by various modern techniques such as FTIR, XRD, SEM, XPS, TEM and TGA. It was successfully utilized for the photodegradation of methyl violet from aqueous solution. Imprinting of ZVI onto GG-cl-SY and presence of H₂O₂ greatly enhanced the photodegradation of methyl violet. Neutral pH favoured the maximum methyl violet degradation. 81% degradation of methyl violet was observed within 120 min in the presence of H₂O₂ and Fe⁰@GG-cl-SY NCH. Scavenger study showed the reactive degradation species were the hydroxyl radicals which were further confirmed by ESR studies. LC-MS study showed the degradation of methyl violet into smaller fragments followed by complete mineralization.