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Factors controlling transport of graphene oxide nanoparticles in saturated sand columns
Author(s) -
Qi Zhichong,
Zhang Lunliang,
Wang Fang,
Hou Lei,
Chen Wei
Publication year - 2014
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.2525
Subject(s) - dlvo theory , ionic strength , graphene , chemistry , humic acid , nanoparticle , chemical engineering , deposition (geology) , ionic bonding , steric effects , oxide , geology , sediment , colloid , ion , organic chemistry , paleontology , fertilizer , aqueous solution , engineering
The authors conducted column experiments and a modeling study to understand the effects of several environmental factors on the aggregation and transport of graphene oxide nanoparticles (GONPs) in saturated quartz sand. The GONPs were negatively charged and stable under the test conditions (0–50 mM NaCl; pH 4.8–9.0), and the Derjaguin–Landau–Verwey–Overbeek (DLVO) calculation indicated that deposition of GONPs was under unfavorable attachment conditions. The GONPs exhibited high mobility even at an ionic strength of 25 mM NaCl. The transport of GONPs was insensitive to the changes of pH (from 5.1 to 9.0), but the presence of 10 mg/L Suwannee River humic acid (SRHA) considerably enhanced transport at high ionic strength (35 mM NaCl), likely via enhanced steric repulsion and significantly inhibited stacking of GO flakes. Varying flow velocity also enhanced transport at high ionic strength. In general, GONPs exhibit greater mobility compared with other carbon nanoparticles because the aggregation and transport of GONPs are more resilient to changes in solution chemistry and hydrodynamic forces that favor aggregation and deposition of nanoparticles. A 2‐site transport model incorporating both the blocking‐affected attachment process and straining effects can effectively model the transport of GONPs. The high mobility of GONPs should be given full consideration in assessing their environmental risks. Environ Toxicol Chem 2014;33:998–1004 . © 2014 SETAC