the calculated kP values are listed in Table 5. The MB
removal rates of the four composites are greatly enhanced
by comparison with the TiO2 samples, especially in the
case of composite S/M, which removed 98% of the MB
from the solution in only 2 min of UV illumination. Under
the same conditions, samples ST-01 and P25 removed only
5 and 24% of the MB respectively. The kP values of the
composites can be fitted by three straight lines in a
log(C(t)/C0) versus t plot. These lines can be interpreted as
reflecting an adsorption- dominated (kP1) stage, a mixture
of adsorption and photodecomposition effects (kP2) and a
photodecomposition-dominated (kP3) stage.