A surfactant interfacial adsorption
process is highly associated
with its micellization behaviors in the water phase, which is of great
fundamental and practical significance in enhanced oil recovery. In
this paper, the typical anionic surfactant 1-dodecanesulfonic acid
sodium (DAS) and nonionic surfactants octylphenol polyoxyethylene
ether-n (OP-n, n = 1, 5, and 10) are introduced to investigate their micellization
behavior and interfacial adsorption process via molecular dynamics
simulation. Number density profiles reveal that the additional OP5
molecules in the water phase generate the mixed micelle with DAS molecules
and greatly promote its interfacial adsorption. Interaction energy
calculation is employed to confirm the interaction of anionic/nonionic
surfactants in the mixed micelle. Then, the radial distribution function,
solvent-accessible surface area, and solvation free energy are calculated
to further explore and verify the adsorption mechanism of the mixed
micelle. It is found that the nonionic surfactant obviously decreases
the hydrophilicity of the mixed micelle in the water phase, which
should be responsible for its intensive tendency of the interfacial
adsorption.
The addition of nanoparticles (NPs) to polymer solutions can effectively improve the rheological and thermal properties of the polymer solution. However, the interaction between NPs and cellulose, a potential alternative for polymers applied in enhanced oil recovery (EOR), has been scarcely reported. In this work, the effects of three typical NPs (AlOOH, SiO 2 , and ZnO NPs) on the rheological properties, emulsifying ability, and resistance to harsh conditions of carboxylic cellulose nanofiber (CCNF) solutions were investigated thoroughly. The results indicate that only AlOOH NPs exert a positive impact on the CCNF's rheological properties, which should be ascribed to the delicate electrostatic attraction between the CCNF and AlOOH NPs. The intensified network of the CCNF/AlOOH system also results in a superior emulsifying performance and temperature and salt tolerance than other mixed CCNF/NPs systems. In the core flooding test, the CCNF/AlOOH system outperforms the individual CCNF system and the conventional partially hydrolyzed polyacrylamide, reflecting the potential of incorporating AlOOH NPs in the CCNF to promote the CCNF's practical application in EOR.
The β-cyclodextrin-acrylamide (CDM-AM) copolymer was prepared from acrylamide and β-CD maleate (CDM) using 60Co γ-ray irradiation method. The optimized preparation conditions for the CDM-AM copolymer are as follows: CDM:AM mass ratio of 1:1; irradiation dose of 4 kGy; and using 20 mL of DMF water solution. The yield rate of CDM-AM was 75% in grams using these synthetic conditions. The effects of the CDM-AM copolymer on the solubility and fungicidal activity of natamycin (NM) and carbendazim (MBC) were investigated. The stability constant of NM·CDM-AM and MBC·CDM-AM complexes at 303 K were of 13,446.06 M−1 and 2595.3 M−1, respectively. The complexes were characterized using phase solubility diagrams, NMR spectra and FT-IR spectra. The analysis of the biological activities of these two complexes indicated that they possessed enhancing fungicidal activities compared to NM and MBC alone.
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