Preparation of pH-Responsive Oil-in-Water Microemulsion Using a Full-Bio-Based Surfactant Containing a Dynamic...

Area of Science:

• Green Chemistry
• Materials Science
• Environmental Science

Background:

• Development of sustainable surfactants is crucial for environmental remediation.
• Bio-based surfactants offer a promising alternative to conventional synthetic surfactants.
• pH-responsive materials are valuable for controlled release and separation applications.

Purpose of the Study:

• To synthesize and characterize a novel pH-responsive, full-bio-based surfactant (Ca-S).
• To prepare and evaluate oil-in-water (O/W) microemulsions using Ca-S for oil-contaminated soil remediation.
• To assess the cytotoxicity and performance of the Ca-S microemulsions.

Main Methods:

• Synthesis of Ca-S from renewable cashew phenol, 5-chloro-2-furanaldehyde, and taurine.
• Structural characterization using Fourier transform infrared spectroscopy (FTIR) and 1H nuclear magnetic resonance (NMR).
• Preparation of limonene-based O/W microemulsions and testing for soil remediation efficiency, cytotoxicity, interfacial tension, and pH responsiveness.

Main Results:

• Ca-S surfactant was successfully synthesized and characterized.
• The Ca-S microemulsions exhibited low interfacial tension and fast response characteristics.
• Optimal pH responsiveness was observed, with rapid and complete phase separation in acidic media (pH < 4) within 5 seconds.
• Microemulsion treatment significantly reduced soil oil content to below 4%.
• Ca-S demonstrated lower cytotoxicity against the A549 cell line.

Conclusions:

• The novel pH-responsive bio-based surfactant Ca-S is effective for oil-contaminated soil remediation.
• The developed microemulsions offer efficient, low-energy, ambient-temperature remediation with excellent pH-triggered separation.
• Ca-S microemulsions show significant potential for sustainable environmental applications, particularly in soil remediation.