Effect of Grafted Copolymer Composition on Iron Oxide Nanoparticle Stability and Transport in Porous Media at High Salinity

Abstract

The transport of engineered nanoparticles in porous media is of interest in numerous applications including electromagnetic imaging of subsurface reservoirs, enhanced oil recovery, and CO 2 sequestration. A series of poly(2-acrylamido-2methyl-1-propanesulfonic acid-co-acrylic acid) (poly(AMPS-co-AA)) random copolymers were grafted onto iron oxide (IO) nanoparticles (NPs) to provide colloidal stability in American Petroleum Institute (API) standard brine (8 wt/wt % NaCl and 2 wt/wt %CaCl 2 , anhydrous basis). A combinatorial approach, which employed grafting poly(AMPS-co-AA) with wide ranges of compositions onto platform amine-functionalized IO NPs via a 1-ethyl-3-(3-(dimethylamino)propyl)carbondiimidecarbondiimide (EDC) catalyzed amidation, was used to screen a large number of polymeric coatings. The ratio of AMPS/AA was varied from 1:1 to 20:1 to balance the requirements of particle stabilization, low adsorption/retention (provided by 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS)), and permanent attachment of stabilizer (provided by acrylic acid (AA)). The resulting nanoparticles remained stable in aqueous suspension despite the extremely high salinity conditions and exhibited low adsorption on silica microspheres. Greater than 91% of applied IO-NP mass was transported through columns packed quartz sand, and the mobility of IO NP increased by ca. 6% when the AMPS to AA ratio was increased from 1:1 to 3:1, consistent with batch adsorption data. In both static batch reactor and dynamic column tests, the observed attachment of IO NPs was attributed to divalent cation (Ca 2+ ) mediated bridging and hydrophobic interactions. Collectively, the rapid, high throughput combinatorial approach of grafting and screening (via batch adsorption) provides for the development of high mobility NPs for delivery in various porous media under high salinity conditions.

Viscosity and stability of ultra-high internal phase CO2-in-water foams stabilized with surfactants and nanoparticles with or without polyelectrolytes

“…35,40 The adsorption of anionic particles to a negatively charged oil-water interface increases with increasing salinity by reducing electrostatic repulsion, both for equilibrium and kinetic reasons. 35,40 However, too much salt may screen the charge to the extent that lack of repulsion results in aggregation of particles, [41][42][43][44][45] thereby breaking the foam. 46 Despite the efforts to facilitate the adsorption of particles to C/W interfaces, C/W foams stabilized with particles alone have had a maximum viscosity of ~ 16 cP up to  = 0.9.…”

Control of magnetite primary particle size in aqueous dispersions of nanoclusters for high magnetic susceptibilities

“…Recently, long term colloidal stability of IO and other NPs was reported even over a wide pH range in high salinity, high temperature brines typically encountered in oil reservoirs [10][11][12][13][14][15][16] . For example polymers containing 2-acrylamido-2-methylpropane sulfonic acid (AMPS), which bind weakly to Ca 2+ , remain extended after coated on ~100 nm IO nanoclusters in American Petroleum Institute brine (API brine, 8% w/w NaCl + 2% w/w CaCl 2 , anhydrous basis) and provide efficient steric and electrostatic stabilization [16][17][18][19][20] . A key step for the crosswell EM imaging technology is to enhance the magnetic susceptibility of the IO cores in the form of an aqueous colloidal dispersion.…”

Experimental study of viscosity properties of emulsion system with SiO 2 nanoparticles.

“…Today we know a large number of nanoparticle types and the methods tor apply them to create the modified systems with new physicochemical properties [10][11][12][13][14][15][16][17].…”