where k is the rate constant which controls process (first order and
pseudo-first order reaction rate constant), A is the Arrhenius
constant, T is the solution temperature in K, Ea is activation energy
(kJ/mol) and R is the ideal gas constant (0.0083 kJ/mol K).
The results of the thermodynamic calculations are shown in
Table 4. Results show that DH values (Table 4) are negative. So the
process was maybe exothermic. This result also supported that the
first and pseudo-first order rate of UV/H2O2 reaction, primarily
decreased by increasing temperature (Fig. 7). According to the
results, we can not say certain expressions, also, the reaction
pathway involved in the dye degradation is complex, with many
unknown reactions occurring.