Khodadoust A P, Bagchi R, Suidan M T, Brenner R C, Sellers N G
Department of Civil and Environmental Engineering, University of Cincinnati, Cincinnati, OH 45221-0071, USA.
J Hazard Mater. 2000 Dec 30;80(1-3):159-74. doi: 10.1016/s0304-3894(00)00286-7.
Removal of PAHs from highly contaminated soil found at a manufactured gas site was evaluated using solvent washing with mixed solvents. The following solvents were considered as water miscible co-solvents in mixed solvents: ethanol, 2-propanol, acetone, and 1-pentanol. In batch solvent extraction of soil, ethanol and 2-propanol were selected as primary components of mixed solvents in addition to 1-pentanol. Using ternary solutions containing either ethanol or 2-propanol with a volume fraction of 1-pentanol ranging from 5 to 25% and a water volume fraction ranging from 5 to 30%, ethanol was more effective than 2-propanol in extracting PAHs from soil. A solvent mixture of 5% 1-pentanol, 10% water and 85% ethanol was selected as the extraction solvent. Using a 1g:4ml soil:solvent extraction ratio, extraction kinetics showed that from 65 to 90% of the extractable PAHs were removed within an hour of contact between soil and solvent. Using this 1g:4ml extraction ratio, PAHs were removed in a three-stage cross-current solvent washing process where the same batch of soil was extracted with clean solvent for 1h in each stage. PAH removals in three-stage cross-current solvent washing were comparable to PAH removals obtained with Soxhlet extraction.
采用混合溶剂进行溶剂洗涤，对在人造煤气厂发现的高污染土壤中的多环芳烃去除情况进行了评估。以下溶剂被视为混合溶剂中与水混溶的共溶剂：乙醇、2-丙醇、丙酮和1-戊醇。在土壤的间歇式溶剂萃取中，除了1-戊醇外，还选择乙醇和2-丙醇作为混合溶剂的主要成分。使用含有乙醇或2-丙醇的三元溶液，其中1-戊醇的体积分数为5%至25%，水的体积分数为5%至30%，乙醇在从土壤中萃取多环芳烃方面比2-丙醇更有效。选择了一种由5% 1-戊醇、10%水和85%乙醇组成的溶剂混合物作为萃取溶剂。使用1g:4ml的土壤:溶剂萃取比例，萃取动力学表明，在土壤与溶剂接触一小时内，65%至90%的可萃取多环芳烃被去除。使用这种1g:4ml的萃取比例，在三级错流溶剂洗涤过程中去除多环芳烃，在每个阶段用干净溶剂对同一批土壤萃取1小时。三级错流溶剂洗涤中的多环芳烃去除率与索氏萃取法获得的多环芳烃去除率相当。
