Photocatalytic degradation of the herbicide terbuthylazine: Preparation, characterization and photoactivity of the immobilized thin layer of TiO2/chitosan

• Preparation of an immobilized photocatalyst for highly contaminated wastewater.
• Cost effective and environmentally friendly materials used for preparation.
• Negligible loss of TiO2 during degradation reactions after treatment.
• Small reduction in specific surface of TiO2 with enhanced adsorption due to chitosan.
• Efficient degradation of a triazine herbicide terbuthylazine to cyanuric acid.

The aim of this study was to immobilize a photocatalytic TiO2 layer on a suitable support material for potential use in a variety of photoreactor designs. The immobilized TiO2/chitosan thin film was used for the photocatalytic treatment of a triazine herbicide, terbuthylazine as representative agrochemical pollutant in the wastewater. The method of preparation was based on the use of a chitosan as binder and glass fiber woven roving material as a support. The employed method was found to be very simple, low cost and quite effective. Several methods of the photocatalyst characterization, such as FE-SEM/EDX, AAS, ICP-MS, TOC and nitrogen adsorption/desorption at 77 K were employed to correlate structural and morphological properties of immobilized TiO2–chitosan/glass fiber woven roving and its photocatalytic properties under UV irradiation. Reaction was performed in a self-constructed batch mode and annular type of the photoreactor. Comparison of thermal, photolytic and photocatalytical degradation of treated terbuthylazine at different reaction conditions was performed in order to get more insight into the photocatalytic performance and reaction mechanism. It was observed that there is no decay in photocatalytic efficiency over a long period of reaction time using for the photocatalytic degradation of terbuthylazine.