Synthesis and Application of Fe-Doped TiO₂ Nanoparticles for Photodegradation of 2,4-D from Aqueous Solution

2,4-Dichlorophenoxyacetic (2,4-D) is a toxic herbicide used to control weeds in agricultural sector. However, its residuals in soil and water are harmful for human and aquatic life. Therefore, the aim of this study was to evaluate the photocatalytic degradation of 2,4-D from aqueous solution using the Fe-doped TiO₂ nanoparticles in the presence of UV and sunlight irradiation. The nanoparticles were synthesized via a mild hydrothermal process. The characteristics of the synthesized nanoparticles were determined using powder X-ray diffraction, Fourier transform infrared and scanning electron microscopy techniques. The effects of different parameters, including pH, nanoparticle dosage, initial 2,4-D concentration and dopant percentage on the degradation of 2,4-D, were investigated. The results demonstrated that the successfully doped nanoparticles had likely pseudo-spherical morphology. The optimum conditions for photocatalytic degradation of 2,4-D obtained at pH 7, nanoparticle dosage = 0.4 g/l, initial 2,4-D concentration = 10 mg/l, dopant percentage = 1.5% and contact time = 120 min. Under the optimal conditions, the photocatalytic degradation efficiencies of 2,4-D under UV and sunlight irradiation were 65 and 72%, respectively. In addition, the findings showed that 2,4-D degradation efficiency increased with increasing dosage of nanoparticles, while it decreased with increasing initial concentration of 2,4-D and initial pH. Therefore, the Fe-doped TiO₂ nanoparticles could be used for the photodegradation of 2,4-D, and it is recommended for the degradation of other organic pollutants from aqueous media especially in tropical areas where a free energy source, i.e., sunlight, is available.