TiO2光催化降解胸腺嘧啶的动力学和机理

摘要

The advanced oxidation processes were examined toward the degradation of thymine (C5H6N2O2), a type of nucleic acid from the pyrimidine family. As observed, the photodegradation of thymine over TiO2 photocatalyst was rapid and significant in aqueous solution under UV irradiation. Different parameters were studied, including the adsorption of thymine onto TiO2 photocatalyst, the kinetics of degradation, and the effect of pH on the photocatalytic properties of thymine degradation. Addi‐tionally, the mineralization of the products obtained upon thymine photodegradation was studied. The disappearance and mineralization rates of thymine during the photocatalytic process were also compared and discussed. The mineralization of nitrogen was also investigated, and the identifica‐tion of the intermediate products was established. Finally, electronic density calculations were used to propose possible chemical pathways for the photodegradation of thymine over TiO2 photocata‐lyst under UV irradiation.%考察了用于降解来自嘧啶家族的一种核酸—胸腺嘧啶(C5H6N2O2)的高级氧化过程。结果发现，在光催化剂TiO2作用下，胸腺嘧啶的光降解进行得很快，且在紫外光照射和水溶液中时更为明显。研究了胸腺嘧啶在TiO2催化剂上的吸附、降解动力学、以及pH值对光催化降解胸腺嘧啶性能的影响。另外，考察了胸腺嘧啶降解产物的矿化；比较和讨论了在光催化过程中胸腺嘧啶的消失和矿化速率。同时还研究了氮的矿化，确立了中间产物的识别方法。最后，采用电子密度计算提出了在紫外光照射下TiO2催化剂上胸腺嘧啶降解的可能化学途径。