Energy & Fuels, Vol.27, No.4, 1772-1778, 2013
Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry Characterization of Tunable Carbohydrate-Based Materials for Sorption of Oil Sands Naphthenic Acids
The potential for sorption and possible degradation of components in oil sands processed water (OSPW) by the use of synthetically engineered co-polymers is receiving growing attention. Recent research has highlighted the sorption of total oil sands naphthenic acid fraction components (NAFCs) by beta-cyclodextrin (beta-CD) co-polymers. The incorporation of beta-CD within co-polymer frameworks represents a novel modular approach with significant potential for controlled tuning of the textural mesoporosity of the sorbents. Herein, we report the Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) characterization of aqueous samples containing oil sands NAFCs following sorption with a range of cyclodextrin-based co-polymers. The materials investigated were beta-CD cross-linked with three different types of diisocyanates, namely, (i) 4,4'-dicyclohexylmethane diisocyanate, (ii) 4,4'-diphenylmethane diisocyanate, and (iii) 1,4-phenylene diisocyanate. Variable sorption of NAFCs was observed according to the cross linking density of the co polymer framework and the nature of the cross-linker unit. Furthermore, the sorption of the NAFCs by the co-polymers was not affected by other parameters, such as metal ions, salinity, and non-oil sands acid fractions present in OSPW. The observation of molecular selective sorption in co-polymer materials containing beta-CD represents an important contribution toward the development of sorbent materials for the controlled removal of oil sands acids in aquatic environments. The FT-ICR MS measurements also contribute further to the understanding of the thermodynamic sorption mechanism of such materials.