紫外辐射强度对土壤中PAHs催化降解的影响

Effect of UV Radiant Intensity on Photocatalytic Degradation of PAHs on Soil Surface

以土壤为介质,菲(Phe)、芘(Pyr)和苯并[a]芘(BaP)为目标污染物,研究了纳米TiO_2和Fe_2O_3为催化剂下,紫外辐射强度对光催化降解多环芳烃及动力学参数的影响。结果表明,随着辐射强度的增加,光催化降解PAHs的速率常数增加,半衰期缩短。当辐射强度从527μW·cm-2增加到1071μW·cm-2,纳米TiO2催化下,BaP光催化降解速率常数从0.0053h-1增加到0.0078h-1,Pyr降解速率常数从0.0017h-1增加到0.0037h-1,Phe降解速率常数从0.0039h-1增加到0.0060h-1;Fe2O3催化下,BaP光催化降解速率常数从0.0049h-1增加到0.0069h-1,Pyr降解速率常数从0.0016h-1增加到0.0036h-1,Phe降解速率常数从0.0038h-1增加到0.0053h-1。随辐射强度的增加,Pyr的光催化降解的速率常数和半衰期变化最大。

This paper studied the photocatalytic degradation of phenanthrene （Phe）, pyrene （Pyr） and benzo[a]pyrene （BaP） in soil as target contaminants and its dynamics using nano-TiO2 or Fe2O3 as catalyst under different UV radiant intensities. The results show that the photo- catalytic degradation rates of the three PAHs （polycyclic aromatic hydrocarbons） increase with the increase of UV irradiation intensity, but the half-life of photocatalytic degradation is decreased. As UV radiant intensity increases from 527 to 1 071 μW·cm^-2 using nano-TiO2 as catalyst, the photocatalytic degradation rate of BaP increases from 0.005 3 h^-1 to 0.007 8 h^-1, Pyr increases from 0.001 7 h^-1 to 0.003 7 h^-1, and Phe increases from 0.003 9 h^-1 to 0.006 0 h^-1, while, using Fe2O3 as catalyst, the photoeatalytic degradation rates of BaP, Pyr and Phe increase from 0.004 9 h^-1 to 0.006 9 h^-1, from 0.001 6 h^-1 to 0.003 6 h^-1, and from 0.003 8 h^-1 to 0.005 3 h^-1 respectively. Of the three contaminates, the photocatalytic degradation rate and half-life of photocatalytic degradation of Pyr vary most greatly with the increase of radiant intensity.