Interaction between oligomeric cationic quaternary ammonium surfactant and green surfactant alkyl polyglycoside

The aggregation behavior of trimeric cationic quaternary ammonium surfactant (Citric-3C₁₂) with nonionic surfactant alkyl polyglycosides (APG) at different molar fractions aqueous solution was investigated using ¹H NMR, surface tension, zeta potential, and dynamic light scattering. The surface activity parameters were evaluated using the Gibbs adsorption theory and an ideal mixing model. The surface tension values and critical micellar concentration of mixed systems were significantly reduced due to the strong synergistic effect between Citric-3C₁₂ and APG. The concentration required by the composite system to reduce the oil-water interfacial tension and to moisten the oil-bearing surface were significantly reduced and the results showed that the oil-water interfacial tension and contact angle of the systems were significantly reduced to 0.03461 mN/m and 40°, respectively. The foaming test showed that the compound system could effectively inhibit the foam formation of APG. In addition, the solubilization capabilities of polycyclic aromatic hydrocarbons (PAHs) in the surfactant and its compounded system were evaluated. As a consequence of the association between the PAHs and micelles, with increasing surfactant concentration, the solubilization capabilities of PAHs increase linearly. Such Citric-3C₁₂ and APG mixed systems have considerable potential in improving the performance of cleaning oily waste.