Colloid Deposition Kinetics with Surface-Active Agents: Evidence for Discrete Surface Charge Effects
✍ Scribed by Gary M. Litton; Terese M. Olson
- Publisher
- Elsevier Science
- Year
- 1994
- Tongue
- English
- Weight
- 230 KB
- Volume
- 165
- Category
- Article
- ISSN
- 0021-9797
No coin nor oath required. For personal study only.
✦ Synopsis
Carboxyl polystyrene latex microspheres ( (245 \mathrm{~nm}) diameter), synthesized willout surfactants (Interfacial Dynamics Corp., Portland, OR), were used for deposition rate experiments in beds of ultrapure granular quartz sand (Unimin, New Canaan, CT). The latex particles and quartz grains were 245 (\mathrm{nm}) and approximately (250 \mu \mathrm{m}) in diameter, respectively. Sizing, cleaning, surface characterization, and experimental procedures were described previously ((12,13)). Phosphate and SDS solutions were equilibrated with surfaces for (2 \mathrm{~h}) prior to electrophoretic mobility and particle rate measurements. Zeta potentials of the latex and quartz were insensitive to equilibration times varying from (30 \mathrm{~min}) to 7 days.
Analytical-grade reagents and deionized water (Milli-Q water, (18 \mathrm{M} \Omega \mathrm{cm}), Millipore, Inc.) were used to prepare primary solutions. Sodium dodecyl sulfate ((99 %), Sigma Chemical Co.) was used without further purification. Critical micelle concentrations (CMC) of the SDS without (\mathrm{NaCl}) and in the presence of (0.3 \mathrm{M} \mathrm{NaCl}\left(6 \times 10^{-4}\right.) and (8 \times 10^{-3} \mathrm{M}), respectively) were consistent with other reported values (14-16). Solutions were buffered at pH 7 with (\mathrm{NaHCO}{3}) equilibrated in air, or (10^{-4} M) phosphate (mixtures of (\mathrm{NaH}{2} \mathrm{PO}{4}) and (\mathrm{Na}{2} \mathrm{HPO}_{4}) ) solutions; (\mathrm{pH} 10) solutions were obtained with (\mathrm{NaOH}). The ionic strength was adjusted with (\mathrm{NaCl}).