Effect of bacteria on the transport and deposition of multi-walled carbon nanotubes in saturated porous media. (June 2016)

• Record Type: Journal Article
• Authors: Han, Peng; Zhou, Dan; Tong, Meiping; Kim, Hyunjung
• Is Part Of: Environmental pollution. Volume 213(2016)
• Page Start: 895
• Page End: 903
• Publication Date: 2016-06
• Subjects: MWCNTs -- Bacteria -- Enhanced transport -- Deposition -- Porous media; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2016.03.058
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: The influence of bacteria on the transport and deposition behaviors of carbon nanotubes (CNTs) in quartz sand was examined in both NaCl (5 and 25 mM ionic strength) and CaCl2 (0.3 and 1.2 mM ionic strength) solutions at unadjusted pH (5.6–5.8) by direct comparison of both breakthrough curves and retained profiles in both the presence and absence of bacteria. Two types of widely utilized CNTs, i.e., carboxyl- and hydroxyl-functionalized multi-walled carbon nanotubes (MWCNT-COOH and MWCNT-OH, respectively), were employed as model CNTs and Escherichia coli was utilized as the model bacterium. The results showed that, for both types of MWCNTs under all examined conditions, the breakthrough curves were higher in the presence of bacteria, while the retained profiles were lower, indicating that the co-presence of bacteria in suspension increased the transport and decreased the deposition of MWCNTs in porous media, regardless of ionic strength or ion valence. Complementary characterizations and extra column tests demonstrated that competition by bacteria for deposition sites on the quartz sand surfaces was a major (and possibly the sole) contributor to the enhanced MWCNTs transport in porous media. Graphical abstract: Highlights: Bacteria increased MWCNTs transport in NaCl and CaCl2 solutions in quartz sand. Bacteria similarly affected MWCNTs transport regardless of surface functionalization. Competition for adsorption sites by bacteria led to the increased MWCNTs transport. Abstract : The presence of bacteria in suspension increased the transport and decreased the deposition of MWCNTs in porous media under all examined solution conditions.