模拟可见光下土壤表面石油的光化学降解研究

在模拟可见光照射下，分析了土壤中的初始含油量、土壤类型和土壤pH值对石油在土壤表面光降解过程的影响，并利用紫外-可见分光光度法(UV-Vis)、气相色谱-氢火焰离子化检测器(GC-FID)和傅立叶红外光谱(FTIR)等方法对石油在光降解过程中的演变规律进行研究.结果表明，石油在土壤表面上的光化学降解行为符合准一级反应动力学，实验测得石油的光解速率常数为0.002 6～0.017 2 h^-1，半衰期为40～267 h.GC-FID分析结果表明，在光降解50 h后，石油的饱和烃组分中高碳数的烷烃相对含量降低，低碳数的烷烃相对含量提高；芳香烃组分的大部分色谱峰有明显地降低或消失.红外光谱分析发现，光照60 h后土壤萃取液中可能产生了羰基类化合物，说明石油在光降解过程中逐渐发生氧化.

Photochemical Degradation of Petroleum on Soil Surfaces Under Simulated Visible Light

The factors influencing photochemical degradation of petroleum on soil surfaces under simulated visible light, such as the initial oil concentrations, soil types and pH, were investigated. The concentrations of petroleum in photolytic processes were analyzed by UV-Vis. GC-FID and FTIR were used for the characterization of petroleum hydrocarbons. Experimental results indicated that photochemical degradation of petroleum on soil surfaces followed pseudo first-order kinetics with the rate constant of 0.0026~0.0172 h-1and half-life of 40~267 h. GC-FID analysis showed that, after 50 h of irradiation, the content of saturated hydrocarbons with longer chain decreased, while the proportion of shorter chain ones increased slightly; in addition, most chromatogram peaks of aromatics weakened or disappeared. After 60 h of photolysis, the appearance of carbonyl compounds in FTIR spectra of the extract from soil demonstrated that petroleum was gradually oxidized in the photolytic process.