Visible light photocatalytic activity of chitosan/poly(vinyl alcohol)/TiO 2 nanocomposite for dye removal: taguchi‐based optimization

This work describes the preparation of chitosan/poly (vinyl alcohol)/titanium dioxide (CS/PVA/TiO 2 ) nanocomposite for its use as a photocatalyst under visible light irradiation. The prepared nanocomposite was characterized by Fourier transform infrared (FT‐IR) spectroscopy, X‐ray diffraction (XRD) and scanning electron microscopy (SEM). The photocatalytic activity of CS/PVA/TiO 2 was evaluated by photocatalytic removal of acid red 14 (AR14) in aqueous solution as a model pollutant. A Taguchi orthogonal array experimental design with an L 16 matrix was employed to optimize the factors affecting the photocatalytic efficiency of CS/PVA/TiO 2 nanocomposite such as: pH, irradiation time, initial dye concentration, and nanocomposite dosage. The optimum conditions were found to be as follows: pH = 3; irradiation time = 120 min; initial dye concentration = 10 mg L −1 , and nanocomposite dosage = 400 mg L −1 . The pH was found to be the most effective factor for dye removal, followed by the nanocomposite dosage. The dye removal during visible‐CS/PVA/TiO 2 process under optimal conditions followed the pseudo‐first‐order reaction model with the rate constants of 0.0188 min −1 . The photocatalytic activity of CS/PVA/TiO 2 nanocomposite dropped very slightly in five consecutive reaction cycles. © 2016 American Institute of Chemical Engineers Environ Prog, 36: 66–72, 2017