title: Effect of bacteria on the transport and deposition of multi-walled carbon nanotubes in saturated porous media.
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.
authors.affiliation: School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, 518055, China; Key Laboratory of Water and Sediment Sciences, Ministry of Education, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Han
authors.affiliation: School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, 518055, China; Key Laboratory of Water and Sediment Sciences, Ministry of Education, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Zhou
authors.affiliation: School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, 518055, China; Key Laboratory of Water and Sediment Sciences, Ministry of Education, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China. Electronic address: tongmeiping@pku.edu.cn.
authors.forename: Meiping
authors.initials: M
authors.lastname: Tong
authors.affiliation: Department of Mineral Resources and Energy Engineering, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju-si, Jeollabuk-do, 561-756, Republic of Korea. Electronic address: kshjkim@jbnu.ac.kr.
authors.forename: Hyunjung
authors.initials: H
authors.lastname: Kim
mesh_terms: D002122:Calcium Chloride / Q000737:chemistry*; D004926:Escherichia coli / Q000502:physiology*; D019015:Geologic Sediments; D037742:Nanotubes, Carbon / Q000737:chemistry*; D009994:Osmolar Concentration; D016062:Porosity; D011791:Quartz; D012822:Silicon Dioxide; D012965:Sodium Chloride / Q000737:chemistry*; D012996:Solutions; D013535:Suspensions
chemical_list: D037742:Nanotubes, Carbon; D012996:Solutions; D013535:Suspensions; D011791:Quartz; D012965:Sodium Chloride; D012822:Silicon Dioxide; D002122:Calcium Chloride
keywords: Bacteria; Deposition; Enhanced transport; MWCNTs; Porous media