Preparation of a filter bed coupled with Mn-TiO2/ZnO nanocomposite for the treatment of micro-pollutants in municipal wastewater

Technical advancement is urgently required for the degradation of micro-pollutants in municipal wastewater. The present study aimed to describe the preparation of a filter-bed Mn-TiO2/ZnO nanocomposite and degradation of micro-pollutants in real-time municipal wastewater obtained from Kesare wastewater treatment plant in Mysore district, India. Activated carbon and sand were used for the preparation of the filter bed, and activated carbon was prepared using agricultural wastes (coconut shells). Meanwhile, the visible light-responsive Mn-TiO2/ZnO composite was prepared using the mild sol-gel technique. The composites were characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, and photocatalytic techniques. High crystallinity, considerable shift in the band gap energy, and adequate photocatalytic activity under the visible light range were observed. In addition, the filter bed coupled with the Mn-TiO2/ZnO nanocomposite functioned efficiently in the degradation of the common pollutants under LED irradiation as the driving source of energy.