Premium
Adsorption of tetracycline on single‐walled and multi‐walled carbon nanotubes as affected by aqueous solution chemistry
Author(s) -
Ji Liangliang,
Chen Wei,
Bi Jun,
Zheng Shourong,
Xu Zhaoyi,
Zhu Dongqiang,
Alvarez Pedro J.
Publication year - 2010
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.350
Subject(s) - adsorption , carbon nanotube , aqueous solution , graphite , chemistry , ionic strength , tetracycline , chemical engineering , humic acid , inorganic chemistry , mesoporous material , organic chemistry , catalysis , fertilizer , biochemistry , engineering , antibiotics
Carbon nanotubes have shown great potential as effective adsorbents for hydrophobic organic contaminants in water treatment. The present study investigated the influence of aqueous solution chemistry on the adsorption of tetracycline to carbon nanotubes. Specifically, the effects of ionic strength (NaCl and CaCl 2 ) and presence of Cu 2+ ion (7.5 mg/L) or dissolved soil or coal humic acids (50 mg/L) on adsorption of tetracycline to single‐walled carbon nanotubes (SWNT), multi‐walled carbon nanotubes (MWNT), and nonporous pure graphite as a model of the graphite surface were systematically estimated. The presence of humic acids suppressed tetracycline adsorption on graphite and MWNT prominently, with stronger effects observed on graphite, but only slightly affected tetracycline adsorption on SWNT. The relatively large humic acid components could not readily access the small interstitial spaces of SWNT and thus were less competitive with tetracycline adsorption. The presence of Cu 2+ ion increased tetracycline adsorption to both SWNT and MWNT through the mechanism of cation bridging, with much larger effects observed on MWNT. This was probably because when compared with the Cu 2+ ions complexed on the surface of SWNT, those on the surface of MWNT having larger mesoporous interstices were more accessible to the relatively bulky tetracycline molecule. Increasing the ionic strength from 10 mM to 100 mM decreased tetracycline adsorption on both SWNT and MWNT, which was attributed to electronic shielding of the negatively charged surface sites. These results show that aqueous solution chemistry is important to tetracycline adsorption on carbon nanotubes. Environ. Toxicol. Chem. 2010;29:2713–2719. © 2010 SETAC