Environmental Engineering Program, Department of Civil Engineering, Auburn University, Auburn, AL 36849, USA.
Nanotechnology. 2012 Jul 27;23(29):294007. doi: 10.1088/0957-4484/23/29/294007. Epub 2012 Jun 28.
Mercury (Hg) is one of the most pervasive and bio-accumulative metals in the environment. Yet, effective in situ remediation technologies have been lacking. This study investigated the effectiveness of a class of soil-deliverable FeS nanoparticles for in situ immobilization of Hg in two field-contaminated soils from a New Jersey site and one sediment from an Alabama site. The nanoparticles were prepared using sodium carboxymethyl cellulose (CMC) as a stabilizer. Transmission electron microscopy measurements revealed a particle size of 34.3 ± 8.3 nm (standard deviation), whereas dynamic light scattering gave a hydrodynamic diameter of 222.5 ± 3.2 nm. Batch tests showed that at an FeS-to-Hg molar ratio of 28:1-118:1, the nanoparticles reduced water-leachable Hg by 79%-96% and the TCLP (toxicity characteristic leaching procedure) based leachability by 26%-96%. Column breakthrough tests indicated that the nanoparticles were deliverable in the sediment/soil columns under moderate injection pressure. However, once the external pressure was removed, the delivered nanoparticles remained virtually mobile under typical groundwater flow conditions. When the Hg-contaminated soil and sediment were treated with 52-95 pore volumes of a 500 mg l(-1) FeS nanoparticle suspension, water-leachable Hg was reduced by 90%-93% and TCLP-leachable Hg was reduced by 65%-91%. The results warrant further field demonstration of this promising in situ remediation technology.
汞（Hg）是环境中最普遍和生物累积性最强的金属之一。然而，有效的原位修复技术一直缺乏。本研究调查了一类可用于土壤的 FeS 纳米颗粒在原位固定 Hg 方面的有效性，这些纳米颗粒用于来自新泽西州的两个现场污染土壤和来自阿拉巴马州的一个沉积物。纳米颗粒是使用羧甲基纤维素钠（CMC）作为稳定剂制备的。透射电子显微镜测量显示粒径为 34.3 ± 8.3nm（标准差），而动态光散射给出的水动力直径为 222.5 ± 3.2nm。批处理测试表明，在 FeS 与 Hg 的摩尔比为 28:1-118:1 时，纳米颗粒将水可提取的 Hg 减少了 79%-96%，并将 TCLP（毒性特征浸出程序）基础浸出率降低了 26%-96%。柱穿透测试表明，在中等注入压力下，纳米颗粒可在沉积物/土壤柱中输送。然而，一旦外部压力被移除，在典型的地下水流动条件下，输送的纳米颗粒几乎是可移动的。当用 500mg/L 的 52-95 个孔隙体积的 FeS 纳米颗粒悬浮液处理 Hg 污染的土壤和沉积物时，水可提取的 Hg 减少了 90%-93%，TCLP 可提取的 Hg 减少了 65%-91%。结果证明了这种有前途的原位修复技术在进一步的现场示范中的合理性。
