Surfactant flooding aims at lowering the interfacial tensions between the oil and water phases to improve the displacement efficiency during oil recovery. However, surfactant losses due to adsorption on the reservoir rock impairs performance of the chemical flooding, consequently renders the process impractical economically. This article presents adsorption equilibrium and kinetics of Zizyphus Spina Christi (ZSC), a new non‐ionic surfactant, onto carbonate rocks. The adsorption tests were conducted at a temperature range of 28–75°C. A conductivity method was employed in this study to measure CMC parameter and surfactant concentration in the aqueous solutions. The equilibrium conditions for the crushed rock samples were obtained after about 2 days. According to the experimental results, the equilibrium data were well‐fitted by the Freundlich isotherm for carbonate samples. Furthermore, the adsorption process is exothermic and obeys the second‐order kinetic model. Such a systematic investigation is very helpful to select a proper surfactant for EOR application and reservoir stimulation in the petroleum industry.
Heteroatom-doped carbon dot (CD)-reinforced flexible,
antioxidant,
and UV-resistant polymeric thin films have been fabricated by a facile
physical compounding strategy associated with the ‘cast and
peel’ technique. The prepared CDs were found to be stable in
aqueous media because of their zeta potential value (−5.85
mV). There was no significant change in the zeta potential values
during 7 days of storage, indicating the long-term stability of CPCDs.
CD-reinforced thermoplastic starch (TPS)/κ-carrageenan hybrid
films have been developed as antioxidants to improve the shelf-life
of agro-products. Besides this, they also qualified for mechanical
strength (>40 MPa), transparency (∼77%), nondeteriorative
dimensional
integrity at a high relative humidity (∼97%), and UV-resistant
properties. For assessing the food preservation behavior, the leaching
of CDs also has been studied by time-dependent sustained release in
different food simulant media, where it showed a gradual alteration
of entrapment efficacy in high-polarity gradient environments. The
mechanism of CD release has been obtained from the non-Fickian fittings
of the initial preplateaued kinetic data. Surprisingly, when these
nanodots were arrested inside the polymer matrix, the film also showed
excellent water vapor impermeability, low moisture retention, sufficient
toughness, and superficial compliance to external flexing and stretching.
Also, CD-based TPS/κ-carrageenan films exhibited strong antioxidant
activity, as determined by 1,1-diphenyl-2-picrylhydrazyl (>85%)
and
2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid assays
(>90%). Thus, these hybrid films could be promoted as ideal alternatives
for food packaging with their thin, flexible, tough, antioxidant,
and moisture-impermeable properties.
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