污染土壤残油的臭氧氧化研究

本研究探讨了臭氧氧化对石油污染土壤生物修复后难降解的残油的去除效应。臭氧投加剂量约20mg03／g土时，臭氧氧化效率最高，达0．3mg总油／mgO3，且土壤石油烃降解茵数量仅下降一个数量级。臭氧作用下残油四组分中芳香烃降解率最高，其次为饱和烃，胶质和沥青质含量升高。臭氧对残油各分子量组分均有降解作用，氧化后残油分子量略有下降。GC-MS结果表明臭氧对各类物质氧化的容易顺序为多环芳烃〉甾烷〉藿烷〉烷基环己烷〉正烷烃；臭氧未改变生物标志物参数；氧化后C8～C22脂肪酸，C15～C22正烷烃和C17--C28烷基环己烷含量增加，并出现了C12-C25脂肪醛，臭氧氧化后残油生物可利用性得到提高，生物降解速率是未氧化对照的2倍。

Removal of residual oil in contaminated soil by ozonation

Residual oil after bioremediation in crude oil contaminated soil could be hardly biodegraded.In this study, column experiments were carried out to evaluate the effects of ozonation of residual oil. Maximum of removal efficiency（0.3mg oil/mg O3）was reached when ozone dosage was about 20 mg/g soil.Under this condition,population of petroleum degrading bacteria was reduced only by 1 order of magnitude.Among the four fractions of oil,aromatics showed highest removal,followed by saturates,and resins and asphaltenesincreased after ozonation.Ozonation was able to remove residual oil with all range of molecular weight, resulting in a slight decrease of average molecular weight of residual oil.GC--MS results indicated that ozone removal rate of different types of contaminants showed following sequence： polycyclic aromatic hydrocarbons（PAHs）~steranes〉 hopanes〉alkyl cyclohexanes〉n--alkanes.Ozonation did not change biomarker parameters.Increase of C~~C22n--alkanes,C17--C20 alkyl cyclohexanes and C8--C22carboxylic acids and production of C11-C25aldehydes were observed after ozonation. Removal rate for biodegradation of ozonated residual oil was twice of the control,indicating that bioavailability of residual oil was improved by ozonation.