In this research, multilayer nano thin films fabricated using poly (allyl amine hydrochloride) (PAH), TiO 2 and poly (styrene sulphonate sodium salt) (PSS), on silica template by Layer-by-Layer (L-b-L) technique and its potential application for the photo degradation of textile and oil refinery wastewater under solar irradiation has been reported. TiO 2 nanoparticles of size less than 5 nm were synthesized using modified sol–gel method and the characterization of the particles are performed using Dynamic Light Scattering (DLS), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Fourier Transform Infra-red Spectroscopy (FTIR). The L-b-L assembly was carried out at pH 2.5 and the development of the thin layers was investigated using UV/Vis spectrophotometer at an absorbance of 230 nm. The morphological characterization of the fabricated film was analyzed using Atomic Force Microscopy (AFM). A comparative study has been carried out using textile and oil refinery effluents for the photo degradation of TiO 2/PSS/PAH thin films and suspension form of TiO 2 by varying the process parameters such as number of bilayers, polymer concentration and solar irradiation time. The TiO 2/Polyelectrolyte multilayer thin films performed extremely well in the reduction of Chemical Oxygen Demand (COD) and Total Organic Carbon (TOC) to the standards. The five-bilayer film considerably reduced the TOC and COD to 85% and 87%, respectively. In TiO 2 suspension form, a reduction in TOC and COD was observed to be 70% and 73.5%, respectively. This study illustrates that immobilized nanoparticles could effectively remove pollutants from wastewater and the process seems to be attractive in the environmental applications.
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