Published on the Web 2/16/2009.
Surface functionalized mesoporous silicas as adsorbents for aromatic contaminants in aqueous solution†
Article first published online: 9 DEC 2009
Copyright © 2009 SETAC
Environmental Toxicology and Chemistry
Volume 28, Issue 7, pages 1400–1408, July 2009
How to Cite
Zhu, D., Zhang, H., Tao, Q., Xu, Z. and Zheng, S. (2009), Surface functionalized mesoporous silicas as adsorbents for aromatic contaminants in aqueous solution. Environmental Toxicology and Chemistry, 28: 1400–1408. doi: 10.1897/08-579.1
- Issue published online: 9 DEC 2009
- Article first published online: 9 DEC 2009
- Manuscript Accepted: 13 JAN 2009
- Manuscript Received: 12 NOV 2008
- Mesoporous silica;
- Surface functional group
A hexagonal mesoporous silica (HMS) and its postfunctionalized counterparts with propyl (P-HMS) and aminopropyl (AMP-HMS) were prepared and characterized by elemental analysis, N2 adsorption, powder x-ray diffraction, Fourier-transform infrared, and surface charge measurements. Batch experiments were further performed to systematically investigate adsorption properties of these materials toward two nonpolar aromatic compounds (pyrene and pentachlorobenzene) and three phenolic compounds (2,4-dichlorophenol, pentachlorophenol, and 4-methyl-2,6-dinitrophenol) in aqueous solutions. The adsorption isotherms were well described by the Freundlich model and varied in adsorption linearity. For HMS and P-HMS, the adsorption of pyrene and pentachlorobenzene was much stronger than that of pentachlorophenol at pH slightly greater than 6. Alternatively, for AMP-HMS, pentachlorophenol and 4-methyl-2,6-dinitrophenol showed comparable or stronger adsorption affinity than the other target compounds did, suggesting that a major role is played by electrostatic interactions of the two phenols. Furthermore, adsorption decreased with increasing pH for all adsorbate-adsorbent combinations except that of pentachlorophenol and 4-methyl-2,6-dinitrophenol on AMP-HMS, which showed bell-shaped curves with the maximum adsorption at pH close to the pKa. The advantages of reversible adsorption and fast adsorption/desorption kinetics (<15 min), as compared to commercial microporous activated carbons, make AMP-HMS a promising candidate to remove selected phenolic compounds in water treatment.