Influence of carboxymethyl cellulose for the transport of titanium dioxide nanoparticles in clean silica and mineral-coated sands.
The transport properties of titanium dioxide (anatase polymorph) nanoparticles encapsulated by carboxymethyl cellulose (CMC) were evaluated as a function of changes in the solute chemical properties in clean quartz, amorphous aluminum, and iron hydroxide-coated sands. While pristine anatase TiO2 nanoparticles (ANTNPs) were completely immobile, the presence of CMC significantly enhanced their mobility. The magnitude of the surface charge exhibited by the CMC-coated anatase TiO2 nanoparticles (CMC-ANTNPs) significantly exceeded that of the uncoated ANTNPs, thereby leading to a negative surface charge over the pH range investigated (2-10). The mobility of CMC-ANTNPs was retarded by the presence of amorphous Fe and Al hydroxide, Na+ (30 mM), and Ca2+ (30 mM). Removal of CMC-ANTNPs was more significant in the presence of either Ca2+ or Fe-hydroxide. More retardation and incomplete breakthrough of the CMC-ANTNPs was observed in the mineral-coated sands. This is possibly due to an order of magnitude increase in the surface area of mineral-coated sands compared with the clean quartz sand grains and the potential for chelation between CMC bound to ANTNPs and Fe and Al hydroxides. Chemical-colloidal interactions such as chemicomplexation and ligand exchange were the most important factor controlling mobility of CMC-ANTNPs in mineral-coated sands.
Joo
Sung Hee
SH
Pegasus Technical Services, Inc. 46 E. Hollister Street, Cincinnati, Ohio 45219, USA.
Al-Abed
Souhail R
SR
Luxton
Todd
T
D000535:Aluminum / Q000737:chemistry; D002266:Carboxymethylcellulose Sodium / Q000032:analysis*; D003102:Colloids / Q000737:chemistry; D004784:Environmental Monitoring / Q000379:methods*; D007501:Iron / Q000737:chemistry; D008903:Minerals / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D016062:Porosity; D012822:Silicon Dioxide / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry*
D003102:Colloids; D008903:Minerals; C009495:titanium dioxide; D012822:Silicon Dioxide; D000535:Aluminum; D014025:Titanium; D007501:Iron; D002266:Carboxymethylcellulose Sodium