Despite
the studies on asphaltene aggregation throughout few decades,
the formation of asphaltene aggregates and subsequent deposition are
still the biggest challenges in the oil industry. Especially, the
role of porphyrins existing in oil naturally on asphaltene aggregation
is not completely understood due to asphaltene’s and porphyrin’s
special structures. Herein, we investigated the influence of tetraphenylporphyrin
(TPP), nickel tetraphenylporphyrin (NiTPP), and vanadium tetraphenylporphyrin
(VOTPP) on asphaltene aggregation by a multiscale approach, which
provides an in-depth understanding of the role of porphyrins on asphaltene
aggregation. UV–vis spectroscopy and fluorescence spectroscopy
were performed to examine the self-aggregation of TPP, NiTPP, and
VOTPP and the influence of porphyrins on the aggregation of asphaltene.
The changes of stacking structures, microscopic structures, and particle
size distributions of co-aggregates of asphaltenes with porphyrins
were analyzed in detail via X-ray diffraction, inverted fluorescence
microscopy, and granulometric distribution, respectively. The characterization
results indicated that the aggregation ability of the porphyrins (TPP,
NiTPP, and VOTPP) was stronger than that of asphaltene and porphyrins
can promote the aggregation of asphaltene, which leads to the increase
of the average aromatic sheet number, aggregation morphology, and
particle size of asphaltene aggregates. Based on experimental analysis,
the possible mechanism by which porphyrins promoted asphaltene aggregation
was elucidated. This research provided new insights into the aggregation
and disaggregation of asphaltenes.
Developing a new and environment-friendly desulfurization strategy for removing thiophenic sulfides from fuel is currently necessary. Fuel desulfurization by molecular inclusion with a novel cyclodextrin-based magnetic nanomaterial copper(II)-β-cyclodextrin@silica@ferroferric oxide (Cu(II)-β-CD@SiO 2 @Fe 3 O 4 ) was proposed for the efficient removal of thiophene (T), benzothiophene (BT), and dibenzothiophene (DBT) in fuel. Cu(II)-β-CD@SiO 2 @Fe 3 O 4 was successfully prepared by the reaction between mono-6-O-toluenesulfonyl-Cu(II)-β-CD and 3-aminopropyltrimethoxysilane functionalized SiO 2 @Fe 3 O 4 , and the structural characterization illustrated that the active desulfurization component Cu(II)-β-CD was evenly immobilized on the surface of SiO 2 @Fe 3 O 4 . Furthermore, Cu(II)-β-CD@SiO 2 @Fe 3 O 4 showed outstanding desulfurization performance for thiophenic sulfides in the order BT > DBT > T on account of the varying molecular inclusion ability of Cu(II)β-CD for the three types of thiophenic sulfides. The optimum immobilized load of Cu(II)-β-CD in Cu(II)-β-CD@SiO 2 @Fe 3 O 4 was 5m%, and room temperature was favorable for the desulfurization process. Cu(II)-β-CD@SiO 2 @Fe 3 O 4 exhibits good regeneration performance. The inclusion interaction between Cu(II)-β-CD and sulfides plays a more dominant role than the coordination interaction of Cu(II) with sulfide and the physical absorption during the desulfurization process. The thiophenic sulfides mainly entered the hydrophobic cavity of Cu(II)-β-CD rather than be adsorbed on the surface of Cu(II)-β-CD@SiO 2 @ Fe 3 O 4 . The results lay the foundation of desulfurization with supramolecular magnetic materials, which is significant for environmental protection and resource saving.
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