title: Mobility enhancement of nanoscale zero-valent iron in carbonate porous media through co-injection of polyelectrolytes.
abstract: The mobility of nanoscale zero-valent iron (nZVI), which is used for in situ groundwater remediation, is affected by chemical and physical heterogeneities within aquifers. Carbonate minerals in porous aquifers and the presence of divalent cations reduce nZVI mobility. This study assesses the potential for enhancing the mobility of polyacrylic acid coated nZVI (PAA-nZVI) in such aquifers through the co-injection of polyelectrolytes (natural organic matter, humic acid, carboxymethyl cellulose, and lignin sulfonate). When applied at the same concentration, all of the polyelectrolytes produced similar enhancement of PAA-nZVI mobility in carbonate porous media. This increase in mobility was a result of increased repulsion between PAA-nZVI and the carbonate matrix. Lignin sulfonate, an environmentally friendly and inexpensive agent, was identified as the most suitable polyelectrolyte for field applications. The greatest increase in PAA-nZVI mobility was achieved with co-injection of lignin sulfonate at concentrations ≥50 mg L(-1); at these concentrations the maximum PAA-nZVI travel distance in carbonate porous media was twice of that in the absence of lignin sulfonate.
authors.affiliation: Department of Environmental Geosciences, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria.
authors.forename: Susanne
authors.initials: S
authors.lastname: Laumann
authors.affiliation: Department of Environmental Geosciences, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria.
authors.forename: Vesna
authors.initials: V
authors.lastname: Micić
authors.affiliation: Department of Environmental Geosciences, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria. Electronic address: thilo.hofmann@univie.ac.at.
authors.forename: Thilo
authors.initials: T
authors.lastname: Hofmann
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D001965:Bromides / Q000032:analysis; D002118:Calcium / Q000032:analysis; D002254:Carbonates / Q000737:chemistry*; D004573:Electrolytes / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007267:Injections; D007501:Iron / Q000737:chemistry*; D008031:Lignin / Q000302:isolation & purification; D053768:Metal Nanoparticles / Q000737:chemistry*; D008962:Models, Theoretical; D010316:Particle Size; D016062:Porosity; D011791:Quartz / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D055672:Static Electricity
chemical_list: D000180:Acrylic Resins; D001965:Bromides; D002254:Carbonates; D004573:Electrolytes; D011791:Quartz; C006903:carbopol 940; D012822:Silicon Dioxide; D008031:Lignin; D007501:Iron; D002118:Calcium
keywords: CMC; Carbonate; Lignin sulfonate; NOM; Nanoparticle transport; Nanoscale zero-valent iron; PAA-nZVI; Polyelectrolyte; Porous media; carboxymethyl cellulose; nZVI; nanoscale zero-valent iron; natural organic matter; polyacrylic acid coated nZVI