Li Hui, Zhao Yong-sheng, Han Zhan-tao, Hong Mei
Institute of Hydrogeology & Environmental Geology, CAGS, Shijiazhuang 050061, China.
Key Laboratory of Groundwater Resources and Environment, Ministry of Education, Jilin University, Changchun 130021, China E-mail:
Water Sci Technol. 2015;72(9):1463-71. doi: 10.2166/wst.2015.308.
The growing use of nanoscale zero-valent iron (NZVI) in the remediation of contaminated groundwater raises concerns regarding its transport in aquifers. Laboratory-scale sand-packed column experiments were conducted with bare and sucrose-modified NZVI (SM-NZVI) to improve our understanding of the transport of the nanoparticles in saturated porous media, as well as the role of media size, suspension injection rate and concentration on the nanoparticle behavior. As the main indicative parameters, the normalized effluent concentration was measured and the deposition rate coefficient (k) was calculated for different simulated conditions. Overall, compared to the high retention of bare NZVI in the saturated silica column, SM-NZVI suspension could travel through the coarse sand column easily. However, the transport of SM-NZVI particles was not very satisfactory in a smaller size granular matrix especially in fine silica sand. Furthermore, the value of k regularly decreased with the increasing injection rate of suspension but increased with suspension concentration, which could reflect the role of these factors in the SM-NZVI travel process. The calculation of k-value at the tests condition adequately described the experimental results from the point of deposition dynamics, which meant the assumption of first-order deposition kinetics for the transport of NZVI particles was reasonable and feasible.
纳米零价铁（NZVI）在受污染地下水修复中的应用日益广泛，这引发了人们对其在含水层中运移的担忧。开展了实验室规模的填砂柱实验，使用裸露的和蔗糖改性的NZVI（SM-NZVI），以增进我们对纳米颗粒在饱和多孔介质中运移的理解，以及介质粒径、悬浮液注入速率和浓度对纳米颗粒行为的作用。作为主要指示参数，测量了归一化流出物浓度，并针对不同模拟条件计算了沉积速率系数（k）。总体而言，与裸露的NZVI在饱和硅胶柱中的高保留率相比，SM-NZVI悬浮液能够轻松穿过粗砂柱。然而，SM-NZVI颗粒在较小尺寸的颗粒基质中，尤其是在细硅胶砂中的运移情况并不十分理想。此外，k值随悬浮液注入速率的增加而有规律地降低，但随悬浮液浓度的增加而升高，这可以反映这些因素在SM-NZVI运移过程中的作用。在测试条件下k值的计算从沉积动力学角度充分描述了实验结果，这意味着NZVI颗粒运移的一级沉积动力学假设是合理可行的。
