title: Effect of seepage velocity on the attachment efficiency of TiO2 nanoparticles in porous media.
abstract: Previously identified relationships between the attachment efficiency (α) and seepage velocity (US) of nanoparticles (NPs) were tested under simulated subsurface transport conditions, where the value of US is typically much less than the US on which they are based. This found an increase in the α value of TiO2 NPs with respect to US, which contradicts previous reports suggesting a constant value or decrease. By comparing the adhesion energy of the TiO2 NPs to sand and the hydrodynamic energy required to detach them, the increase of α with respect to US is found to be due to the difference in the magnitude of US considered; with 6.1E-05 to 1.3E-03ms(-1) used in previous studies, whereas the current study uses a value in the range from 2.4E-06 to 4.9E-04ms(-1). Only one of the previous models predicting α showed a similar increase of α with US, which was the result of it employing low velocities to examine the effects of organic matter. The current findings therefore suggest that previously determined relationships between α and US need to be further developed to incorporate more variables before they can be effectively used to describe or predict the subsurface transport of TiO2 NPs.
authors: Center for Water Resource Cycle, Green City Technology Institute, Korea Institute of Science and Technology, Seoul 136-791, Republic of Korea;(2).
authors: Changwoo
authors: C
authors: Kim
authors: Center for Water Resource Cycle, Green City Technology Institute, Korea Institute of Science and Technology, Seoul 136-791, Republic of Korea;(2); Energy Environment Policy and Technology, Greenschool, Korea University-KIST, Seoul 136-701, Korea. Electronic address: seunglee@kist.re.kr.
authors: Seunghak
authors: S
authors: Lee
mesh_terms: D006812:Humic Substances / Q000032:analysis; D007700:Kinetics; D053758:Nanoparticles / Q000737:chemistry*; D016062:Porosity; D012822:Silicon Dioxide / Q000737:chemistry; D014025:Titanium / Q000737:chemistry*
chemical_list: D006812:Humic Substances; C009495:titanium dioxide; D012822:Silicon Dioxide; D014025:Titanium
keywords: Attachment efficiency; Nanoparticle transport; Seepage velocity; Titanium dioxide nanoparticle