Heterogeneous photocatalytic degradation of 3-nitroacetophenone in TiO2 aqueous suspension

The photocatalytic mineralization of 3-nitroacetophenone (3-NAP) by TiO2-P25 in water suspension has been investigated as a function of pH. The reaction of 3-NAP disappearance follows first-order kinetics whatever the pH, however the order kinetic of photomineralization depends on the acidic condition. At pH 3.8, we have a pseudo-first-order kinetic, whereas at higher pH the mineralization rate follows a reaction rate of zero-order. The determination of the pathway for the photomineralization of 3-NAP is not easy, because of the presence of two substituants (NO2 and COCH3) on the aromatic ring and especially of the very small concentration of by-products in solution. However we have observed the formation of hydroxylated 3-NAP by GC-MS.