Visualization of NAPLs in multiphase systems in porous media is important for determining contaminant transport in the environment. In this study, magnetic resonance imaging (MRI) was used to confirm the recent observations of mobilisation of a light non aqueous phase liquid (LNAPL) trapped in wet sand under natural drying conditions of the wet porous medium. Visualization of LNAPL (motor oil) and water mobility during the drying of wet glass beads (0.5 mm) in a cylindrical glass column (15 mm ID, 45 mm long) was obtained using spin echo-based NMR microimaging performed at 500 MHz, corresponding to a field of ca. 11.75 T. Sagittal and axial images of LNAPL and water in the porous medium were obtained at a spatial resolution of 59 μm/pixel at different time intervals. A rise of 15–20 mm was observed in the presence of evaporation of water as compared to a 2–3 mm rise in the absence of evaporation in a time span of about 1400 min. The spatio-temporal MRI scans of the water and LNAPL in the glass column reveals that LNAPL rise occurs when the water evaporation front reaches the LNAPL layer. This implied that the enhanced LNAPL rise was strongly linked to the process of water evaporation. A linear correlation of the MRI signal intensities of LNAPL and water with reference to different saturation levels of LNAPL and water in the porous media was obtained. This calibration information was used to quantify the saturation levels of the LNAPL and water during the drying process. These findings show the application of non-invasive techniques such as MRI in quantifying and understanding the mechanism of fate and transport of LNAPLs in porous media, towards effective environmental quality assessment.

多孔介质中多相系统中NAPL的可视化对于确定环境中的污染物传输非常重要。在这项研究中，磁共振成像（MRI）用于确认在湿多孔介质的自然干燥条件下，捕获在湿沙中的轻质非水相液体（LNAPL）流动的最新观察结果。使用在500 MHz下进行的基于旋转回波的NMR显微成像，可以在圆柱形玻璃柱（15 mm内径，45 mm长）中干燥湿玻璃珠（0.5 mm）的过程中观察LNAPL（发动机油）和水的迁移率到一个领域。11.75 T.在不同时间间隔以59μm/像素的空间分辨率获得了多孔介质中LNAPL和水的矢状和轴向图像。在大约1400分钟的时间内，存在水蒸发的情况下观察到上升了15–20 mm，而没有蒸发的情况下观察到上升了2–3 mm。玻璃柱中水和LNAPL的时空MRI扫描显示，当水蒸发前沿到达LNAPL层时，LNAPL升高。这表明，LNAPL的增加与水蒸发过程密切相关。获得了LNAPL和水的MRI信号强度相对于多孔介质中LNAPL和水的不同饱和度的线性相关性。该校准信息用于定量干燥过程中LNAPL和水的饱和度。