期刊
SCIENCE OF THE TOTAL ENVIRONMENT
卷 718, 期 -, 页码 -出版社
ELSEVIER
DOI: 10.1016/j.scitotenv.2020.137427
关键词
Carboxymettyl cellulose; Mobility; Nanoscale zero-valent iron; Stability; Sulfidation; Transport
资金
- National Natural Science Foundation of China [41877357, 51908500]
- National Key Research and Development Programof China [2018YFC1802002]
- Key R&D Program of Zhejiang Province [2020C03083]
- Natural Science Foundation of Zhejiang Province [LR16E080003]
Sulfidation can enhance the reactivity and longevity of nanoscale zero-valent iron (nZVI), but little is known about its effect on the fate and transport of nZVI in saturated porous media. This work compared the stability and mobility of carboxymethyl cellulose (CMC) stabilized nZVI (CMC-nZVI) and sullidated nZVI (CMC-S-nZVI) particles in saturated porous media. After sulfidation, the hydrodynamic size of CMC-S-nZVI was 100-150 nm larger than CMC-nZVI due to enhanced adsorption of CMC onto the S-nZVI surface, which was facilitated by the bidentate bridging interaction between CMC and the FeSx phase on S-nZVI. Of note is that they had a similar core size and zeta potential. In comparison to CMC-nZVI, CMC-S-nZVI exhibited less physical settling (0-5% vs. 5-73%) and chemical dissolution (2-10% vs. 3-27%) within 55 min under the same ionic conditions (Na+, K+ < 200 mM; Al3+ < 0.75 mM). Column breakthrough experiments showed that both CMC-S-nZVI and CMCnZVI had relatively high mobility in saturated porous media. However, CMC-S-nZVI exhibited greater breakthrough (C/C-0 =0.57-1.0) and corresponding greater mass recovery rates than the corresponding CMC-nZVI (C/C-0 = 0.44-1.0) under most of the experimental conditions (e.g., different ion type and concentration, flow rate, and input concentration). The fitted colloid filtration theory model was in good agreement with experiments. This work suggests that in addition to the significant reactivity and longevity improvements demonstrated in other studies, CMC-S-nZVI is also more mobile than CMC-nZVI suggesting that CMC-S-nZVI has many of the characteristics favorable for field application. (C) Elsevier B.V. All rights reserved.
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