Atmospheric Pressure Photoionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry Characterization of Tunable Carbohydrate-Based Materials for Sorption of Oil Sands Naphthenic Acids

• Published in: Energy & fuels Vol. 28; no. 3; pp. 1611 - 1616
• Main Authors: Headley, John V, Peru, Kerry M, Mohamed, Mohamed H, Wilson, Lee, McMartin, Dena W, Mapolelo, Mmilili M, Lobodin, Vladislav V, Rodgers, Ryan P, Marshall, Alan G
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Washington, DC American Chemical Society 20.03.2014
• Subjects: Applied sciences; Atmospheric pressure; Copolymers; Crosslinking; Diisocyanates; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fuels; Naphthenic acids; Oil sands; Photoionization; Sorption; Characterization; Sorption; Fourier transformation; Photoionization; Naphthenic oil; Cyclotron resonance; Mass spectrometry; Tar sand
• ISSN: 0887-0624; 1520-5029
• DOI: 10.1021/ef401640n

Synthetically engineered copolymers are receiving growing attention for sorption and possible degradation of components in oil sands processed water (OSPW). β-Cyclodextrin (β-CD) copolymers, for example, have been shown in recent studies of electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) to adsorb oil sands naphthenic acid fraction components (NAFCs). Herein, we report complementary results for atmospheric pressure photoionization (APPI) for characterization of NAFCs in OSPW samples following sorption with cyclodextrin-based copolymers. The materials investigated were β-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. The APPI studies revealed variable sorption for a complementary range of NAFCs with compound classes not detected by ESI. For example, sorption was observed for new classes of NAFCs: HC, N1O1, N1O2, N1O3, N1O4, N1O5, N2O1, N2O2, and N2O3, from OSPW in accordance with the nature of the cross-linker unit of the copolymer and the structure of the NAFCs. Sorption of NAFCs in general was more pronounced for β-CD copolymers cross-linked with 4,4′-dicyclohexylmethane diisocyanate, particularly for the O2 class that was amenable to negative-ion APPI detection. In contrast to the 75% attenuation of O2 species observed for sorption to the copolymer cross-linked with 4,4′-dicyclohexylmethane diisocyanate, little or no sorption was observed for the O2 series with positive-ion APPI. The O2 series is presumably mixtures of classical naphthenic acids and dihydroxy components with a range of different structures. The complementary nature of the APPI and the prior ESI results contribute further to the quality and understanding of the sorption mechanism of the copolymers.