Quantifying the influence of humic acid adsorption on colloidal microsphere deposition onto iron-oxide-coated sand

Modeling colloid deposition on a protein layer adsorbed to iron-oxide-coated sand

“…For the BTC of double microsphere pulse experiment (DPE PC), the higher inflection point developed on the second microsphere pulse BTC (Supplement Figure S3) indicates that fewer number of deposition sites remained due to site coverage by microspheres deposited through the first pulse. Kretzschmar et al (1995) and Yang et al (2010) also observed this type of behaviour in multiple pulse column experiments.…”

“…Materials: With the exception of the organic matter (protein), all materials and apparatus employed in column experiments were the same as those employed by Yang et al (2010).…”

“…Microsphere suspension was prepared and dispersed ultrasonically in the same way as described in Yang et al (2010) (See Supplement).…”

Organic matter induced mobilization of polymer-coated silver nanoparticles from water-saturated sand

“…It seems that the coating detachment process was completed in a relative short period (5 min) since no further significant reduction in size occurred. The significantly higher final particle size than the AgNP core (40 nm) implied that not all PVP coatings were detached, otherwise the hydrodynamic size shall comply with the TEM measured size (Yang et al, 2010). Since PVP binds on AgNP in three different ways (via N, O, or both N and O) with different binding strengths (Mdluli et al, 2011), it is possible that not all but only the weak PVP-AgNP bonds were broken by the adsorbed organic molecule.…”

“…The ironoxide coating is expected to have double effect on AgNP deposition. First, it made the medium surface positive (Yang et al, 2010) and thus attractive to the negative AgNP core by EDL interaction. On the other hand, it reduced the PVP sorption sites, since PVP could not adsorb on the hydrophobic iron oxide coating (Torn et al, 2003;Li and Logan, 2004) but attach to the uncoated silica surface by forming a hydrogen bond between the oxygen atoms in PVP and the surface silanols (functional groups with the connectivity Si-O-H) in the uncoated silica (Cooper et al, 2013).…”