Synthesis and Characterization of N and Fe-Doped TiO(2) Nanoparticles for 2,4-Dimethylaniline Mineralization

The present study aimed to evaluate the feasibility of developing low-cost N- and Fe-doped TiO(2) photocatalysts for investigating the mineralization of 2,4-dimethylaniline (2,4-DMA). With a single anatase phase, the photocatalysts showed high thermal stability with mass losses of less than 2%. The predominant oxidative state is Ti(4+), but there is presence of Ti(3+) associated with oxygen vacancies. In materials with N, doping was interstitial in the NH(3)/NH(4+) form and for doping with Fe, there was a presence of Fe-Ti bonds (indicating substitutional occupations). With an improved band gap energy from 3.16 eV to 2.82 eV the photoactivity of the photocatalysts was validated with an 18 W UVA lamp (340–415 nm) with a flux of 8.23 × 10(−6) Einstein s(−1). With a size of only 14.45 nm and a surface area of 84.73 m(2) g(−1), the photocatalyst doped with 0.0125% Fe mineralized 92% of the 2,4-DMA in just 180 min. While the 3% N photocatalyst with 12.27 nm had similar performance at only 360 min. Factors such as high surface area, mesoporous structure and improved E(bg), and absence of Fe peak in XPS analysis indicate that doping with 0.0125% Fe caused a modification in TiO(2) structure.