Degradation of chlorophenol by photocatalysts with various transition metals

In this research, the photocatalytic degradation of 4-chlorophenol (4-CP) in TiO₂ aqueous suspension was studied. TiO₂ photocatalysts were prepared by sol-gel method. The dominant anatase-structure on TiO₂ particles was observed after calcining the TiO₂ gel at 500 °C for 1 hr. Photocatalysts with various transition metals (Fe, Cu, Nd, Pd and Pt) loading were tested to evaluate the effect of transition metal impurities on photodegradation. The photocatalytic degradation in most cases follows first-order kinetics. The maximum photodegradation efficiency was obtained with TiO₂ dosage of 0.4 g/L, retention time of 1 min and air flow rate of 2,500 cc/min. The photodegradation efficiency with Pt-TiO₂ or Pd-TiO₂ is higher than pure TiO₂ powder. The optimal content value of Pt and Pd is 2 wt%. However, the photodegradation efficiency with Fe(1.0 wt%)-TiO₂ and Cu(1.0 wt%)-TiO₂ is lower than pure TiO₂ powder. This paper was prepared at the 2004 Korea/Japan/Taiwan Chemical Engineering Conference held at Busan, Korea between November 3 and 4, 2004.