Poly(acrylic acid) coating induced 2-line ferrihydrite nanoparticle transport in saturated porous media
- 251 Downloads
Iron oxide and iron nanoparticles (NPs) have been used effectively for environmental remediation, but are limited in their applications by strong retention in groundwater-saturated porous media. For example, delivery of NPs to large groundwater reservoirs would require large numbers of injection wells. To address this problem, we have explored polymer coatings as a surface engineering strategy to enhance transport of oxide nanoparticles in porous media. We report here on our studies of 2-line ferrihydrite NPs and the influence of poly (acrylic acid) (PAA) polymer coatings on the colloidal stability and transport in natural sand-packed column tests simulating flow in groundwater-saturated porous media. Measurements were also made of zeta potential, hydrodynamic diameter, and polymer adsorption and desorption properties. The coated NPs have a diameter range of 30–500 nm. We found that NP transport was improved by PAA coating and that the transport properties could be tuned by adjusting the polymer concentration. Our results demonstrate that a high stability of oxide particles and improved transport can be achieved in groundwater-saturated porous media by introducing negatively charged polyelectrolytes and optimizing polymer concentrations.
KeywordsPolymer coating Iron oxide nanoparticles Ferrihydrite Stability Transport Adsorption Groundwater
- Chen S (2007) Polymer-coated iron oxide nanoparticles for medical imaging. PhD thesis, Massachusetts Institute of TechnologyGoogle Scholar
- Cornell RM, Schwertmann U (2003) The Iron oxides: structure, properties, reactions, occurrences and uses, 2nd ed. Wiley-VCH, New yorkGoogle Scholar
- Hunter RJ (1981) Zeta potential in colloid science: principles and applications. Academic Press, New York, pp 20–85Google Scholar
- Orwoll RA, Yong CS (1999) Polymer Data Handbook. Oxford University Press, Newyork, pp 252–253Google Scholar