Fig. 6 illustrates the 3DEEM fluorescence spectra in the first
240 min of UV irradiation at a pH of 9.0. There are humic-like,
fulvic-like and protein-like fluorophores in the solution at 0 min.
After 60 min of irradiation, the intensities of the fulvic-like and
protein-like fluorophores remain nearly constant while the humiclike
fluorophore disappears. However, with further irradiation, the
intensities of the fulvic-like and protein-like fluorophores decrease
gradually.