活性碳载体对TiO2光催化降解Cl2CHCOOH性能的影响

研究了活性碳(AC)载体对TiO₂光催化降解Cl₂CHCOOH性能的影响.结果表明,加入AC载体能提高TiO₂的光催化反应速度,而且AC加入方法及含量有明显影响.本文探讨了TiO₂光催化性能提高的原因.

THE EFFECT OF ACTIVE CARBON SUPPORT ON PHOTOCATALYTIC DEGRADATION OF DICHLOROACETIC ACID FOR TiO2

The photocatalytic degradation of dichloroacetic acid in the aqueous solution was studied using pure TiO 2 and TiO 2 supported on active carbon as photocatalysts. It was found that the photocatalytic reaction rate of TiO 2 was increased by the presence of active carbon support, but the TiO 2/AC prepared by adding active carbon during the formation of TiO 2 sol exhibited much higher photocatalytic activity than TiO 2+AC formed by mechanical mixture of TiO 2 particles and active carbon in the suspension. The apparent rate constants, K Cl - for Cl - production were 6.72×10 -3 ,3.72×10 -3 and 3.45×10 -3 min -1 for TiO 2/AC, TiO 2+AC and TiO 2 respectively. The photocatalytic activity of TiO 2/AC having various AC content was also compared. With AC mass fraction of 5%- 20% the K Cl - for TiO 2/AC was obviously larger than that for TiO 2, but the result was contrary to this for higher AC mass fraction(≥30%). The present results have clearly demonstrated that because as TiO 2 was supported on active carbon, the effective surface area of the photocatalysts and their adsorbability for organic molecules can be increased, providing high concentration environments of organic molecules around TiO 2 particles and resulting to the enhancement of photocatalytic activity of TiO 2.