Photocatalytic Degradation of 2,4-Dinitrophenol Using TiO₂ in Aqueous Solution

A new method was developed to synthesize uniform anatase TiO₂ nanocrystals by the hydrolysis of titanium tetraisopropoxide in nitric acid–isopropyl alcohol aqueous solutions at 353 K. The samples were characterized by XRD, TEM, FE-SEM, and specific surface area determination. In this work, the photocatalytic degradation of 2,4-dinitrophenol in the presence of TiO₂ using ultraviolet (UV) light source was investigated in a batch reactor. The effects of various factors, namely TiO₂, pH, temperature and concentration, on the degradation performance of 2,4-DNP were studied. The photocatalytic degradation of 2,4-DNP follows the pseudo-first-order kinetics. In acidic or alkaline conditions, the photocatalytic degradation efficiency of 2,4-DNP was greater than that in neutral conditions. Thermodynamic studies have also been carried out and values of standard free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°) were calculated.