Influence of gravity on transport and retention of representative engineered nanoparticles in quartz sand

Fate of TiO2nanoparticles in the environment: a review on the transport and retention behavior in the soil compartment

“…Gravity is the most natural factor which can easily influence the transport and retention behavior of TiO 2 NPs or colloids in the soil compartment; hence, its effect on the behavior of NPs in the soil environment was monitored. 52,56 The observed data revealed that this effect is more pronounced when the NP size is larger (>2 μm) and/or they are dense in nature.…”

“…57 Also, the zeta potential values of the TiO 2 NPs and the porous medium (quartz) are positive and negative, respectively, at this pH, which indicates the favorable deposition condition between the two (NPs and quartz). 52…”

“…The column experiments were performed 52 in two different orientations relative to gravity, i.e., the up-flow orientation (negative gravity) and the down-flow orientation (positive gravity) as well as under different solution conditions of pH (5.0 and 7.0) and I.S. (0.1 mM NaCl and 10.0 mM NaCl solutions).…”

Nanoparticles Surface as a Spheroidal Defect in the Parent Material

“…No less mysterious gravity differs in that its manifestations are universal -gravitational forces do not show any selectivity at the acting on a material, regardless of its composition and electronic structure. [48,49] In contrast to this, the result of the action of a magnetic field on a material is highly dependent on its composition, structure, shape and other factors. Materials due to their behavior in an external magnetic field are roughly divided into two unequal groups: magnetic (their minority) and all the rest -"non-magnetic".…”

Co-transport of gold nanospheres with single-walled carbon nanotubes in saturated porous media

“…State-of-the-art ENM transport studies have systematically evaluated the effects of various material properties and background chemistries of a wide set of materials (Petosa et al 2012), e.g., fullerenes (nC 60 ), carbon nanotubes (CNTs), nano-scale zero-valent iron (nZVI), titanium dioxide (TiO 2 ), zinc oxide (ZnO), and silver nanoparticles (AgNPs). Theinfluence of solution chemistry [pH and Ionic Strength (Godinez and Darnault 2011), organic matter (Thio et al 2011)], ENM characteristics [size and size distribution (Phenrat et al 2009), concentration (Phenrat et al 2009), shape (Afrooz et al 2013b), surface charge (El Badawy et al 4 2013), synthesis method (Chowdhury et al 2012a), surface coating (Tripathi et al 2011), and magnetic properties (Hong et al 2009)], collector properties [grain size distribution (Mattison et al 2011) and flow conditions (Cai et al 2015)] on ENMs' mobility have also been reported. In addition to the aforementioned experimental investigations, efforts have been made to predict and validate ENM transport theoretically by employing clean-bed filtration theory (CFT) (He et al 2009).…”