In order to determine the kinetics of photodegradation

In order to determine the kinetics of photodegradation, the relationship between ln (C0/Ct ) and irradiation time was plotted (as inset in Figure 11a). It was found that the degradation reaction of RC under the catalyst is basically obeys to the first order reaction kinetics. The values of the rate constant can be obtained from the slope of the ln(C0/Ct) = k.t, The rate constant is k = 0,07567 min-1. The slow kinetics of dyes degradation after certain time limit is due to: (i) difficulty in converting the N-atoms of dye into oxidized nitrogen compounds, (ii) the slow reaction of short chain aliphatics with •OH radicals and (iii) the short lifetime of photocatalyst because of deactivation of active sites by deposition of degradation products