Hibiscus sabdariffa extract modified magnetic polymer nanocomposite for azo dyes removal from aqueous samples

Abstract In the present investigation, an environmental-friendly, inexpensive and efficient protocol for the synthesis of membrane nanocomposite of Polyvinyl alcohol (PVA)/Hibiscus sabdariffa L. extract containing magnetic nanoparticles (Fe3O4@SiO2@Hs@PVA) reported for the first time and characterized by Fourier-transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), X-ray diffraction (XRD), Thermal gravimetric analysis (TGA), Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). This magnetic nanocomposite was applied as a novel heterogeneous iron- Fenton like nanocatalyst for the successful removal of two azo dyes; methylene blue (MB) and methyl orange (MO) from aqueous solution. The effects of different variables such as nanocatalyst dosage, H2O2 volume, temperature and contact time on the decolorization efficiency was investigated via Draper-Lin small composite design (SCD) and optimized by response surface methodology (RSM). Under the optimized conditions, the decolorization percentages of methyl orange and methyl red using as-prepared magnetic nanocomposite were obtained to be >99%. Reusability experiments has been performed for 9 consecutive runs showing its incredible physicochemical stability. The obtained results showed that the Fe3O4@SiO2@Hs@PVA nanocomposite could be employed as a magnetically separable and cost-effective nanocatalyst for the degradation of the target azo dyes in environmental water samples.