Photocatalytic degradation of phenol and polycyclic aromatic hydrocarbons in water by novel acid soluble collagen-polyvinylpyrrolidone polymer embedded in Nitrogen-TiO₂

The photocatalytic degradation of phenol, naphthalene, fluoranthene, phenanthrene, pyrene, benz[a]anthracene, and anthracene was investigated using a novel nitrogen-doped TiO₂/acid-soluble collagen-polyvinyl pyrrolidone nanocomposite (N-TiO₂/ASC-PVP). Characterization through X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) revealed that the nanocomposite consists of spheroidal particles smaller than those of undoped TiO₂. X-ray photoelectron spectroscopy (XPS) confirmed the incorporation of nitrogen within the TiO₂ lattice, appearing as both substitutional nitrogen (O–Ti–N) and interstitial nitrogen (Ti–O–N). The degradation process followed apparent first-order kinetics, with the N-TiO₂/ASC-PVP calcined at 200°C and 400°C demonstrating high photocatalytic degradation efficiencies. The nanocomposite achieved a remarkable 98.6% degradation of the targeted compounds within 120 minutes at a concentration of 10 mg/L. The enhanced photocatalytic activity under visible light can be attributed to several factors: the smaller crystal size, increased surface hydroxyl groups, improved visible light absorption, and a reduced band gap energy. This N-TiO₂/ASC-PVP photocatalyst shows significant potential for applications in materials science and nanotechnology, supporting advancements in environmental and energy-related fields.