Enhanced distribution of humic acid-modified nanoscale magnesia for in situ reactive zone removal of Cd from simulated groundwater
Enhanced distribution of humic acid-modified nanoscale magnesia for in situ reactive zone removal of Cd from simulated groundwater
复制标题
增强腐植酸改性纳米氧化镁的分布，用于原位反应区去除模拟地下水中的镉
DOI：
10.1016/j.envpol.2018.10.105
复制
发表时间：
2019
影响因子：
8.9
通讯作者：
Fu Heng
中科院分区：
文献类型：
--
作者：
Koju Neel Kamal;Song Xin;Lin Na;Xu Keke;Fu Heng
纳米颗粒在多孔介质中的有效注入和分布被认为是基于注射的原位修复的一个艰巨的技术障碍。提高纳米颗粒在含水层中的流动性的一种方法是使用表面改性剂。在这项研究中，纳米氧化镁（NMgO），一种创新的和有效的补救材料，从地下水中去除镉（Cd），改性与负电荷和生态友好的腐殖酸，以提高其在含水层中的流动性。设计、建造了一个二维反应器（60 × 50 × 10 cm），其中有2个注入威尔斯井和30个监测威尔斯井，并在实验室中进行了填砂以模拟饱和含水层。模拟含水层预污染镉模拟羽在地下水。评价了注入的未改性的NMgO和腐殖酸改性的NMgO浆料在反应器中的分布。基于视觉观察，腐殖酸改性的NMgO的影响半径（ROI）估计为约5 cm，而对于未改性的NMgO没有ROI是明显的，因为它们聚集在注入威尔斯的底部。在不同的时间间隔，在所有30个监测威尔斯中的Cd和镁（Mg）的浓度进行了监测，以评估镉的去除效果。穿透曲线分析表明，腐殖酸促进了NMgO在饱和多孔介质中的迁移。此外，在注入NMgO之前和之后的硅砂的扫描电子显微镜-能量色散X射线（SEM-EDX）表征的结果证实了在注入威尔斯的35 cm向下梯度处存在来自腐殖酸改性的NMgO的5.78%的Mg和来自未改性的NMgO的0.19%的Mg，这与从穿透曲线得出的结论一致。
Efficient injection and distribution of nanoparticles in porous media are considered a formidable technical hurdle for injection-basedin situremediation. One approach to enhance the mobility of nanoparticles in an aquifer is to use surface modifiers. In this study, nanoscale magnesia (NMgOs), an innovative and effective remedial material for cadmium (Cd) removal from groundwater, was modified with the negatively charged and eco-friendly humic acid to enhance its mobility in aquifers. A two-dimensional reactor (60 × 50 × 10 cm), with 2 injection wells and 30 monitoring wells was designed, constructed, and sand-packed in the laboratory to simulate a saturated aquifer. The simulated aquifer was pre-contaminated with Cd to simulate a plume in groundwater. The distribution of injected unmodified NMgOs and humic acid-modified NMgOs slurry were evaluated in the reactor. The radius of influence (ROI) of humic acid-modified NMgOs was estimated to be approximately 5 cm based on visual observation, while no ROI was apparent for the unmodified NMgOs because of their aggregation at the bottom of the injection wells. The concentrations of Cd and magnesium (Mg) were monitored in all 30 monitoring wells at different time intervals to evaluate the effectiveness of Cd removal. The breakthrough curve analysis revealed that humic acid enhances the transport of NMgOs in the saturated porous media. Furthermore, the results of scanning electron microscopy-energy dispersive x-ray (SEM–EDX) characterization of silica sand before and after injection of NMgOs verified the presence of 5.78% of Mg from humic acid-modified NMgOs and 0.19% from unmodified NMgOs at 35 cm downgradient of the injection wells, which are consistent with the conclusion drawn from the breakthrough curves.