The photocatalytic degradation expe

The photocatalytic degradation experiment was carried out in
a column glass reactor. Three 1 W-LED lights with a radiant
wavelength of 450e475 nm (light-emitting diode, Shenzhen
Lanbaoli Photo-electricity Technology Co., Ltd., China) were
used as the visible light source, and the photon flux determined
by a UV e An Ultraviolet Meter (Photoelectric Instrument
Factory of Beijing Normal University, China) was about
2  103 mW/cm2 at 420 nm and 0 mW/cm2 at 365 nm.
The lights were placed tightly against the reactor, and were
spaced 120 from each other, a cutoff filter was placed
between the light and reactor to insure there is no light below
400 nm, as shown in Fig. 1. The column glass container of
2.5 cm i.d. and 10 cm height was placed concentrically inside
the box, and filled with 20 mL solution. The reaction was
performed in an open system in which the top surface of the
photoreactor was open to the atmosphere. Prior to photoreaction,
the solution containing photocatalyst and phenol was
magnetically stirred in darkness for 30 min to establish
adsorptionedesorption equilibrium.Prior to the experiment, the PFT/TiO2 suspension and
Cr(VI) ion concentration in all batch experiments were maintained
at 1 g/L and 15 mg/L, respectively. The pH value of
reaction solution was prepared at pH 3.0 with the addition of
0.05 mol/L HNO3 or NaOH. And visible-light-induced photocatalytic
reduction of the metal ion Cr(VI) was carried out in
air atmosphere.