Remediation of azo-dyes based toxicity by agro-waste cotton boll peels mediated palladium nanoparticles

The present study reports an environmental benign route for the synthesis of palladium nanoparticles (Pd NPs) using agro-waste empty cotton boll peels aqueous extract for the first time. Surface Plasmon Resonance (SPR) band in absorption spectrum of Pd NPs at 275 nm confirmed the formation of Pd NPs by using UV–Vis spectroscopy. Crystalline nature of Pd NPs was confirmed by powder XRD analysis. Size and morphology was studied by transmission electron microscopy (TEM). The cotton peels extract acted as a source of phytochemicals which primarily reduced Pd⁺² to Pd⁰ nanoparticles (Pd NPs) and imparted stability of Pd NPs by surface capping. The characteristic functional groups of phytochemicals in extract and capped Pd NPs surfaces were identified by FT-IR analysis. Catalytic activity of the synthesised Pd NPs was checked against reduction of hazardous azo-dyes such as Congo red, Methyl orange, Sunset yellow and Tartrazine with NaBH₄ as electron donors. Pd NPs catalysed reduction of all azo-dyes by NaBH₄ in aqueous medium was monitored by UV–visible spectroscopy where Pd NPs mediated transfer of electrons from NaBH₄ to azo-dyes as carrier. The synthesized Pd NPs acted as a good catalyst and could be a promising material in degrading toxic azo-dyes from industrial effluents and wastewater.