Krajangpan Sita, Bermudez Juan J Elorza, Bezbaruah Achintya N, Chisholm Bret J, Khan Eakalak
Department of Civil Engineering, North Dakota State University, Fargo, ND 58105, USA.
Water Sci Technol. 2008;58(11):2215-22. doi: 10.2166/wst.2008.925.
Zero-valent iron nanoparticles (nZVI) were successfully entrapped in calcium alginate beads. The potential use of this technique in environmental remediation using nitrate as a model contaminant was investigated. Kinetics of nitrate degradation using bare nZVI (approximately 35 nm dia) and entrapped nZVI were compared. Calcium alginate beads show promise as the entrapment medium for nZVI for possible use in permeable reactive barriers for groundwater remediation. Based on scanning electron microscopy images it can be inferred that the alginate gel cluster acts as a bridge that binds the nZVI particles together. Kinetic experiments with 100, 60, and 20 mg NO3--N L(-1) indicate that 50-73% nitrate-N removal was achieved with entrapped nZVI as compared to 55-73% with bare nZVI over a 2 h period. The controls ran simultaneously show little or no NO3--N removal. Statistical analysis indicates that there was no significant difference between the reaction rates of bare and entrapped nZVI. The authors have shown for the first time that nZVI can be effectively entrapped in Ca-alginate beads and no significant decrease in the reactivity of nZVI toward the model contaminant (nitrate here) was observed after the entrapment.
零价铁纳米颗粒（nZVI）成功包裹于海藻酸钙珠粒中。研究了该技术在以硝酸盐作为模型污染物的环境修复中的潜在应用。比较了使用裸露的nZVI（直径约35 nm）和包裹的nZVI降解硝酸盐的动力学。海藻酸钙珠粒有望作为nZVI的包裹介质，可能用于地下水修复的可渗透反应屏障。基于扫描电子显微镜图像可以推断，海藻酸凝胶簇起到了将nZVI颗粒结合在一起的桥梁作用。对100、60和20 mg NO3--N L(-1)进行的动力学实验表明，在2小时内，包裹的nZVI实现了50 - 73%的硝酸盐 - N去除，而裸露的nZVI为55 - 73%。同时进行的对照实验显示几乎没有或没有NO3--N去除。统计分析表明，裸露的和包裹的nZVI的反应速率之间没有显著差异。作者首次表明，nZVI可以有效地包裹在海藻酸钙珠粒中，并且包裹后未观察到nZVI对模型污染物（此处为硝酸盐）的反应活性有显著降低。
