Toxic metal immobilization in contaminated sediment using bentonite- and kaolinite-supported nano zero-valent iron

• Published in: Journal of nanoparticle research : an interdisciplinary forum for nanoscale science and technology Vol. 16; no. 8; pp. 1 - 15
• Main Authors: Tomašević, D. D., Kozma, G., Kerkez, Dj. V., Dalmacija, B. D., Dalmacija, M. B., Bečelić-Tomin, M. R., Kukovecz, Á., Kónya, Z., Rončević, S.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.08.2014; Springer; Springer Nature B.V
• Subjects: Aquatic environment; Bentonite; Characterization and Evaluation of Materials; Chemistry and Materials Science; Condensed matter: structure, mechanical and thermal properties; Contaminated sediments; Diffusion coefficient; Diffusion in nanoscale solids; Diffusion in solids; Exact sciences and technology; Humic acids; Inorganic Chemistry; Kaolinite; Lasers; Leaching; Lead; Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties; Materials Science; Metals; Nanoparticles; Nanotechnology; Optical Devices; Optics; Photonics; Physical Chemistry; Physics; Research Paper; River basins; Sediment pollution; Speciation; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Transport properties of condensed matter (nonelectronic); Zinc; Mitigation method; Toxic metal; Leaching tests; Supported nano zero-valent iron; Stabilisation; Environmental effects; Immobilization; Iron; Nanostructures; Nanometer scale; Bentonite; Kaolinite; Humic acids; Diffusion coefficient; Diffusion
• ISSN: 1388-0764; 1572-896X
• DOI: 10.1007/s11051-014-2548-2

The objective of this study was to investigate the possibility of using supported nanoscale zero-valent iron with bentonite and kaolinite for immobilization of As, Pb and Zn in contaminated sediment from the Nadela river basin (Serbia). Assessment of the sediment quality based on the pseudo-total metal content (As, Pb and Zn) according to the corresponding Serbian standards shows its severe contamination, such that it requires disposal in special reservoirs and, if possible, remediation. A microwave-assisted sequential extraction procedure was employed to assess potential metal mobility and risk to the aquatic environment. According to these results, As showed lower risk to the environment than Pb and Zn, which both represent higher risk to the environment. The contaminated sediment, irrespective of the different speciation of the treated metals, was subjected to the same treatment. Semi-dynamic leaching test, based on leachability index and effective diffusion coefficients, was conducted for As-, Pb- and Zn-contaminated sediments in order to assess the long-term leaching behaviour. In order to simulate “worst case” leaching conditions, the test was modified using acetic and humic acid solution as leachants instead of deionized water. A diffusion-based model was used to elucidate the controlling leaching mechanisms; in the majority of samples, the controlling leaching mechanism appeared to be diffusion. Three different single-step leaching tests were applied to evaluate the extraction potential of examined metals. Generally, the test results indicated that the treated sediment is safe for disposal and could even be considered for “controlled utilization”.