Spectroscopic Study of Nitroaromatic-Smectite Sorption Mechanisms
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- 作者：Cliff T. Johnston ; Maurilio Fernandes de Oliveira ; Brian J. Teppen ; Guangyao Sheng ; and Stephen A. Boyd
- 刊名：Environmental Science & Technology
- 出版年：2001
- 出版时间：December 15, 2001
- 年：2001
- 卷：35
- 期：24
- 页码：4767 - 4772
- 全文大小：122K
- 年卷期：v.35,no.24(December 15, 2001)
- ISSN：1520-5851
文摘
Sorption mechanisms of 1,3- and 1,4-dinitrobenzene,1,3,5-trinitrobenzene (TNB), dinitro-o-creasol, and 6-sec-butyl-2,4-dinitrophenol (DINOSEB) on smectite wereinvestigated using FTIR spectroscopy and HPLC methods.A quantitative method was developed that establisheda direct link between the HPLC and the FTIR data. Freundlichsorption values ranged from 47 (L g-1) for 1,3,5-TNB to3.7 for DINOSEB and showed that the extent of nitroaromaticcompounds (NAC) sorption was strongly dependent onthe number and position of the nitro substituents as wellas other substituents and steric effects. The amount of 1,3,5-TNB sorbed to smectite was strongly influenced by thenature of the exchangeable cation. Furthermore, theexchangeable cation significantly influenced the positionsand relative intensities of the vibrational modes of the-NO2 groups. The strongest perturbations were observedfor cations with lower enthalpies of hydration (e.g., K+) andincluded a red shift of the 
asym(NO) band, a concomitantblue shift of the sym(NO) band. These changes wereaccompanied by a 2-fold increase in the relative intensityof the asym(NO) band relative to the intensity of the sym(NO) band. Molecular quantum mechanics calculations wereused to rationalize frequency shifts in terms of nitroaromaticinteractions with interlayer cations. Results indicatethat the sorption of NACs to smectite surfaces is controlledlargely by the hydration characteristics of the exchangeablecation, which regulates both cation-nitroaromaticcomplexation and swelling of the smectite.
asym(NO) band, a concomitantblue shift of the sym(NO) band. These changes wereaccompanied by a 2-fold increase in the relative intensityof the asym(NO) band relative to the intensity of the sym(NO) band. Molecular quantum mechanics calculations wereused to rationalize frequency shifts in terms of nitroaromaticinteractions with interlayer cations. Results indicatethat the sorption of NACs to smectite surfaces is controlledlargely by the hydration characteristics of the exchangeablecation, which regulates both cation-nitroaromaticcomplexation and swelling of the smectite.