Fe3+、Ce3+掺杂TiO2光催化降解气相二苯并呋喃

以气相二苯并呋喃为研究对象,考察了在TiO2、Ce3+/TiO2和Fe3+/TiO2 3种不同光催化剂作用下,反应物初始浓度、湿度、气体循环速率和光强等因素对间歇式光催化反应速率的影响,并建立了估算和测定二苯并呋喃光催化反应常数和Langmuir吸附常数的数学模型和方法.结果表明,Fe3+和Ce3+掺杂修饰TiO2光催化剂后,提高了对二苯并呋喃的光催化降解活性,其中Fe3+/TiO2光催化活性最高;随着二苯并呋喃初始浓度的增大,其光催化降解速率也随之增大;适量的水蒸气存在可以促进二苯并呋喃的降解,但当水蒸气过量后,反而阻碍二苯并呋喃光催化降解;随着气体循环速率加快和光强的增大,二苯并呋喃光催化降解初始速率也随之增大;TiO2、Ce3+/TiO2和Fe3+/TiO2光催化降解二苯并呋喃反应速率常数k分别为34.54×10-5、36.23×10-5和37.95×10-4mg.(min.m2)-1.

Photocatalytic Degradation of Gaseous Dibenzofuran by TiO2 Doped with Fe3+, Ce3+

The gaseous photocatalytic degradation of dibenzofuran, dioxins-like substance, was investigated by using TiO_2 , Ce~(3+) /TiO_2 and Fe~(3+)/TiO_2 as photocatalysts. The batch-type photocatalytic reaction experiments were conducted, and the effects of initial concentration of reactant, humidity, circulation flow rate and light intensity on the photocatalytic degradation of dibenzofuran were studied. And the models and methods for estimating photocatalytic reaction constants and Langmuir adsorption constants were proposed. Results showed that the photocatalytic activity of the TiO_2 photocatalyst was obviously improved after doping with Fe~(3+) and Ce~(3+) , and the photocatalytic activity of Fe~(3+) /TiO_2 was the best in three photocatalysts. The degradation rate of dibenzofuran increased with the increase of the initial concentration of gaseous dibenzofuran in the batch-type photocatalytic reaction system. The photocatalytic degradation of gaseous dibenzofuran was enhanced when proper quantities of water vapor existed. However, it would be inhibited if there was excessive water vapor. As the circulation flow rate and the light intensity increased, the photocatalytic degradation rate of gaseous dibenzofuran also increased. The photocatalytic reaction rate coefficients of dibenzofuran on the photocatalysts TiO_2, Ce~(3+)/TiO_2 and Fe~(3+)/TiO_2 were 34.54 × 10~(-5) , 36.23 × 10~(-5) and 37.95 × 10~(-4) mg · ( min · m~2 )~(-1) respectively.