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 nan...

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Bibliographic Details
Published in:Environmental science & technology 2009-07, Vol.43 (13), p.4954-4959
Main Authors: Joo, Sung Hee, Al-Abed, Souhail R, Luxton, Todd
Format: Article
Language:English
Subjects:
Aluminum - chemistry
Applied sciences
Carboxymethylcellulose Sodium - analysis
Cellulose
Chemical compounds
Colloids - chemistry
Environmental Monitoring - methods
Environmental Processes
Exact sciences and technology
Iron - chemistry
Minerals - chemistry
Nanoparticles
Nanoparticles - chemistry
Nanotechnology - methods
Pollution
Porosity
Sand & gravel
Silica
Silicon Dioxide - chemistry
Titanium - chemistry
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Summary: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.
ISSN:0013-936X
1520-5851
DOI:10.1021/es900329d