End Group Effect on Widening Clay Layered Spacing by Polyoxyalkylene Amine-Salts and Their Application on Crude Oil Adsorption
Date Issued
2009
Date
2009
Author(s)
Hsu, Ru-Siou
Abstract
Poly(oxypropylene)-segmented monoamine salts (POP-monoamine) of different molecular weights including 600, 1000, and 2000 g/mol were first time used for ionic exchange reaction with sodium montmorillonite (Na+-MMT) to probe the clay intercalation mechanism. The expansion of the clay layered spacing was more substantial for achieving 74 Å XRD d spacing than the analogous di-amine salts of POP-2000 Mw blocks (52 Å). Hydrophobic effect may create a separated phase in the silicate plate interlayer by the influence of amine end groups. As a result, monoamine is different from diamine and expanding the MMT spacing more than 10 Å than the diamine. The modified clay could self-assemble at the toluene/water interface to form film, exhibiting an aligned an ordered structure as revealed by TEM and SEM. The POP-intercalated MMT (or POP-MMT) is considered to be organic-inorganic amphiphiles possessing organic solvent dispersing affinity as well as a unique property of lower critical aggregation temperature (LCAT) in water. The poly(oxypropylene) segment is exhibiting its hydrophobic phase aggregation in accordance with the amine functionalities through different noncovalent bonding interactions. he potential application for adsorbing crude oil spills is demonstrated. The maximum adsorption capacities of crude oil occurred at the POP/MMT weight ratio of 50 wt % and responded to the environmental temperature or a “lower critical aggregation temperature (LCAT)” property. The adsorption of crude oil occurred in two stages. The first order adsorption is the formation of POP/MMT interaction with crude oil through the MMT layer spacing by an increasing d spacing. The second order adsorption is a micelle-like aggregation of POP/MMT/oil units into a large oil lump. Further addition of 10 wt % magnetic Fe3O4 nanoparticles enabled the adsorbed oil lumps to be removable under a magnetic field.
Subjects
Poly(oxypropylene)amine
Intercalation
Layered Silicate
Amphiphilic
Montmorillonite
Type
thesis
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