Visible light photocatalytic activity of chitosan/poly(vinyl alcohol)/TiO₂ nanocomposite for dye removal: taguchi‐based optimization

Abstract

This work describes the preparation of chitosan/poly (vinyl alcohol)/titanium dioxide (CS/PVA/TiO2) 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/TiO2 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 L16 matrix was employed to optimize the factors affecting the photocatalytic efficiency of CS/PVA/TiO2 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/TiO2 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/TiO2 nanocomposite dropped very slightly in five consecutive reaction cycles. © 2016 American Institute of Chemical Engineers Environ Prog, 36: 66–72, 2017

Dye removal from wastewater by the cross‐linked blend nanofiber and homogenous surface diffusion modeling

“…Thus, it is necessary to remove dyes from aqueous phase using effective processes [1][2][3][4][5][6][7][8][9][10]. They can prevent the penetration of oxygen and light and reduce the photosynthetic activities in aquatic environments.…”

Review of the Advancements on Polymer/Metal Oxide Hybrid Nanocomposite‐Based Adsorption Assisted Photocatalytic Materials for Dye Removal

“…For example, the performance of chitosan/ polyvinyl alcohol/TiO 2 (CS/PVA/TiO 2 ) hybrid composite in sorption-photocatalytic degradation of acid red 14 (AR 14) is highly affected by the pH of the reaction media. [58] The AR 14 molecule is an acidic dye-containing two sulfonated (SO 3 À ) groups, while chitosan is a weak base containing amine groups (À NH 2 ). [59] In acidic media, pH below its pKa, chitosan molecule will be ionized into ammonium ion (À NH 3 + ).…”

“…[82,83] In addition, their porous structure and the presence of some functional groups also enhance surface adsorption, which makes the dye molecules easily accessible on the surface of the photocatalyst. [58,84,85] Thus, the photocatalytic dye degradation reaction by such polymer/metal oxide hybrid nanocomposite is solely sensitized by metal oxides. [86] The photocatalytic degradation of congo red by barium crosslinked alginate/carboxymethyl cellulose/TiO 2 , [63] methyl orange by Polyether sulfone/TiO 2 , [82] TiO 2 /chitosan, [86] and zein/ poly (propylene carbonate)/TiO 2 (zein/PPC/TiO 2 ), [87] malachite green by polymeric poly (dl-lactide-co-glycolide)-zinc oxide nanocomposite (PLGA-ZnO-N C ), [84] Methylene blue by ZnOpoly (methyl methacrylate) (ZnO-PMMA), [88] acid yellow and acid blue by zein/TiO 2 , [83] neutral red and crystal violet by polyacrylamide/calcium alginate/TiO 2 (PAM/CA/TiO 2 ), [85] acid red 14 (AR14) by chitosan/polyvinyl alcohol/TiO 2 (CS/PVA/ TiO 2 ), [58] Rhodamine B by chitosan/CdO/NiO, [29] methylene blue by poly(acryl nitrile)/ZnO(PAN/ZnO), [53] and acid black 1 by gelatin assisted TiO 2 /BiOI (g-TiO 2 /BiOI), [89] are among polymer/ metal oxide hybrid composites which prevent nanoparticle agglomeration, improve stability and recyclability of the catalyst and increase adsorption of dye molecules to the catalyst surface.…”