Novel guar gum/Al2O3 nanocomposite as an effective photocatalyst for the degradation of malachite green dye.

Abstract Guar gum/Al 2 O 3 (GG/AO) nanocomposite was prepared using simple and cost effective sol–gel method. This nanocomposite was characterized by several analytical techniques viz. scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermal analysis (TGA/DTA), Fourier transform infrared spectroscopy (FTIR) and ultraviolet-visible spectroscopy (UV–vis). The FTIR analysis confirmed that GG/AO composite material was formed. TEM images inferred the particle size in the range between 20 and 45 nm. GG/AO nanocomposite exhibited good photocatalytic performance for malachite green (MG) dye (dye initial concentration 1.5 × 10 −5  M) degradation from aqueous phase. The adsorption followed by photocatalysis and coupled adsorption/photocatalysis reaction achieved about 80% and 90% degradation of MG dye under solar irradiation. Antibacterial test showed the excellent activity of GG/AO nanocomposite against Staphylococcus aureus .