Details

Autor(en) / Beteiligte

• Georgi, Anett
• Schierz, Ariette
• Mackenzie, Katrin
• Kopinke, Frank-Dieter

Titel

Colloidal activated carbon for in-situ groundwater remediation — Transport characteristics and adsorption of organic compounds in water-saturated sediment columns

Ist Teil von

• Journal of contaminant hydrology, 2015-08, Vol.179, p.76-88

Ort / Verlag

Netherlands: Elsevier B.V

Erscheinungsjahr

2015

Link zum Volltext

Quelle

Elsevier ScienceDirect Journals

Beschreibungen/Notizen

• Colloidal activated carbon can be considered as a versatile adsorbent and carrier material for in-situ groundwater remediation. In analogy to other nanoremediation approaches, activated carbon colloids (ACC) can be injected into the subsurface as aqueous suspensions. Deposition of ACC on the sediment creates a sorption barrier against further spreading of hydrophobic pollutants. This study deals with the optimization of ACC and their suspensions with a focus on suspension stability, ACC mobility in saturated porous media and sorption efficiency towards organic contaminants. ACC with an appropriate particle size range (d50=0.8μm) were obtained from a commercial powdered activated carbon product by means of wet-grinding. Among the various methods tested for stabilization of ACC suspensions, addition of humic acid (HA) and carboxymethyl cellulose (CMC) showed the best results. Due to electrosteric stabilization by adsorption of CMC, suspensions remained stable even at high ACC concentrations (11gL−1) and conditions typical of very hard water (5mM divalent cations). Furthermore, CMC-stabilized ACC showed high mobility in a water-saturated sandy sediment column (filter coefficient λ=0.2m−1). Such mobility is a pre-requisite for in-situ installation of sorption or reaction barriers by simple injection-well or direct-push application of ACC suspensions. Column experiments with organic model compounds proved the efficacy of ACC deposits on sediment for contaminant adsorption and retardation under flow-through conditions. [Display omitted] •Activated carbon colloids (ACC) with optimized particle size obtained by wet milling•Stable ACC suspensions at high solid concentrations obtained with CMC as stabilizer•ACC stabilized with humic acid or CMC shows excellent mobility in sediment columns.•ACC deposited on sediment fully available for adsorption of hydrophobic organic contaminants