CAJ | 학술논문

选择四氯乙烯(PCE)作为典型重非水相液体(DNAPLs)污染物,进行 PCE 在二维砂箱中的运移及修复实验,采用一种改进光透法探讨DNAPL在含不同透镜体非均质含水层中的运移和饱和度分布特性.在此基础上,考察非离子表面活性剂(吐温80)对DNAPL的原位冲洗修复效果.结果表明,在模拟天然地下水流条件下,当 PCE 运移到达各透镜体时,PCE 均未进入透镜体而是在其上方聚集形成污染池,然后逐渐侧向扩散,即使在较粗透镜体(20/30目和40/60目石英砂按1：1质量比例混合)上也无法进入.吐温80对 PCE 的修复效果显著,冲洗58h后,94.2%的PCE被去除.表面活性剂的引入能够减小PCE和水的界面张力,界面张力的减小量可达38.8dyn/cm,相应各透镜体上覆界面处的毛细压力水头值会有不同程度的减小,在较粗透镜体上的PCE可以穿透透镜体并继续向下运移.透镜体的毛细截留作用会限制修复后期的修复效率,修复75,3520min的修复效率分别为0.63,0.05g/g,其中较粗透镜体上截留的PCE相对其他较细透镜体容易移出.
선택사록을희(PCE)작위전형중비수상액체(DNAPLs)오염물,진행 PCE 재이유사상중적운이급수복실험,채용일충개진광투법탐토DNAPL재함불동투경체비균질함수층중적운이화포화도분포특성.재차기출상,고찰비리자표면활성제(토온80)대DNAPL적원위충세수복효과.결과표명,재모의천연지하수류조건하,당 PCE 운이도체각투경체시,PCE 균미진입투경체이시재기상방취집형성오염지,연후축점측향확산,즉사재교조투경체(20/30목화40/60목석영사안1：1질량비례혼합)상야무법진입.토온80대 PCE 적수복효과현저,충세58h후,94.2%적PCE피거제.표면활성제적인입능구감소PCE화수적계면장력,계면장력적감소량가체38.8dyn/cm,상응각투경체상복계면처적모세압력수두치회유불동정도적감소,재교조투경체상적PCE가이천투투경체병계속향하운이.투경체적모세절류작용회한제수복후기적수복효솔,수복75,3520min적수복효솔분별위0.63,0.05g/g,기중교조투경체상절류적PCE상대기타교세투경체용역이출.
Tetrachloroethylene (PCE) was selected as the representative DNAPL to carry out the migration experiments in a two-dimensional (2-D) sandbox, and a modified light transmission visualization method was used to study the migration and saturation distribution characteristics in heterogeneous aquifer containing different lenses, based on which, the recovery effect of DNAPL by situ flushing with a non-ionic surfactant (Tween 80) was investigated. The results showed that, when reaching the low permeability lenses, PCE did not migrate downward but pooled on the surfaces then migrated sideways on the surface of the coarser lens which was packed with a 1:1mixture of 20/30 mesh accusand and 40/60 mesh accusand in homogeneous saturated porous media under natural water flow velocity condition. The recovery effect of PCE made by Tween 80 was prominent, 94.2%of PCE was removed after 58 hours of flushing. The introduction of surfactant could decrease the interfacial tension (IFT) between PCE and water, and reduce the capillary pressure value on the surface of the lenses to varying degrees. Decrease of interfacial tension between PCE and water could reach 38.8dyn/cm. PCE on the surface of coarser lens could penetrate the lens and migrated downward during the surfactant flush. The remediation efficiency was restrained by the capillary intercept in the late stage of the recovery, and the remediation efficiency at 75min and 3520min were 0.63g/g and 0.05g/g respectively. The PCE entrapment on coarser lens could be removed more easily than that on finer lenses.