New Answers to the Optical Interrogation of Asphaltenes: Complex States of Primary Aggregates from Steady-State Fluorescence Studies

This study examined the states of primary asphaltene aggregates in 0.2–27 mg/L toluene solutions via steady-state fluorescence emission (SSFE) techniques. The experimental results do not support the conventional models of “consecutive aggregation” with interdependent states of aggregates and with mo...

Full description

Saved in:
Bibliographic Details
Published in:Energy & fuels 2016-10, Vol.30 (10), p.8226-8235
Main Authors: Evdokimov, Igor N, Fesan, Aleksey A, Losev, Aleksandr P
Format: Article
Language:English
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:This study examined the states of primary asphaltene aggregates in 0.2–27 mg/L toluene solutions via steady-state fluorescence emission (SSFE) techniques. The experimental results do not support the conventional models of “consecutive aggregation” with interdependent states of aggregates and with monotonic increase of the complexity of aggregates with increasing concentration. The observed concentration dependencies of SSFE spectra were strongly nonmonotonic, with several intervals of “apparent re-entrance” when the measured properties in more-concentrated solutions returned to those in less-concentrated ones. Literature analysis revealed qualitatively similar nonmonotonic/“re-entrant” effects of asphaltene concentration in experimental results of other research groups. We suggest that the complex effects of concentration are consistent with autonomous kinetic routes to the independent states of molecular aggregates observed in most experiments with asphaltenes in good solvents.
ISSN:0887-0624
1520-5029
DOI:10.1021/acs.energyfuels.6b01943