Ternary system of TiO2 confined chitosan–polyaniline heterostructure photocatalyst for the degradation of anionic and cationic dyes
P. Sirajudheen, Resha Kasim Vellattu Chola, Sivakumar Vigneshwaran, Nabeena Chettithodi Poovathumkuzhi, Basheer Meethale Chelaveettil, Sankaran Meenakshi
Abstract
Herein, report the preparation of TiO2 tethered chitosan–polyaniline composite (TiO2 @CS–PANI) by heterogeneous chemical polymerisation technique. The crystallographic, morphological and optical properties of the fabricated TiO2 @CS–PANI composite was described with the aid of powder X-ray diffraction (PXRD), Fourier transform infra red (FTIR) spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), photoluminescence (PL) and thermogravimetry-differential scanning calorimetric (TGA-DSC) analysis. The diffuse reflectance spectra (DRS) evaluation confirmed that the TiO2 @CS–PANI band gap was reduced compared to that of TiO2 from 3.2 eV to 2.98 eV. The prepared photocatalyst was utilised for the degradation of toxic Methylene Blue (MB) and Methyl Orange (MO) dye molecules from water in visible light photocatalysis, and is studied in detail. The initial dye concentration of 30 mg/L and photocatalyst dosage of 100 mg were used to investigate the degradation capacity of the composite. The TiO2 @CS–PANI composite shows extreme degradation efficiency of 92.3% and 89.5% towards MB and MO dyes, respectively. The photocatalyst offers an improved reusability up to five successive cycles. The results established that the TiO2 @CS–PANI composite could be used as an effective photocatalyst to mineralise toxic dye molecules containing water/wastewater.