The effect of pH on NB photocatalytic degradation was evaluated over the range 4–10, into solution with 2.52 104 M pollutant content, at optimum photocatalyst dose (0.5 wt.% Fe–
TiO2 = 250 mg/L) for irradiation time between 60–240 min. The NB degradation efficiencies and rate constants for several initial pH conditions are presented in Table 3.