where kobs is the apparent reaction rate constant, n is the order of
the reaction, t is the reaction time. Values of kobs were determined
from the slope of a graph which was a plot between eln (C/C0) and
reaction time, t. The value R2 for linear regressionwas calculated to
exhibit the tendency of the reaction pattern to be described as
pseudo-first order. From Fig. 5, results show that TCF catalyst canremove Cr(VI) from aqueous solution with a higher efficiency than
TiO2 powder. The photocatalytic reduction rate of Cr(VI) was
0.56 102 and 0.03 102 ppm-min for TCF and TiO2 powder,
respectively. Values of kobs from pseudo-first order equation were
0.74 102 and 0.03 102 min1 for TCF and TiO2 powder
respectively. This pattern suggests that the photocatalytic performance
can be enhanced by the impregnation of TiO2 into chitosan/
xylan hybrid matrix. The Cr(VI) photocatalytic activity of the TCF
was tremendously higher than that of the TiO2 powder. This
increasing of Cr(VI) removal performance may have been attributable
to the high adsorption ability of Cr(VI) on TCF surface where
plenty of TiO2 is promptly reacted with Cr(VI).