Synthesis, properties and application of novel asymmetric Gemini surfactants based on alkali lignin

This study introduced a novel surfactant with outstanding surface and interfacial properties: the asymmetric lignin-based Gemini surfactant (ALGS). And this surfactant was synthesized by integrating a Gemini structure with a biomass surfactant of lignin-amine. Subsequently, comprehensive investigations into the physico-chemical properties of ALGS were conducted. Surface tension measurements revealed that the critical micelle concentration (CMC) of ALGS ranged from 0.0098 mmol/L to 0.072 mmol/L, signifying their high surface activity. And the ALGS surfactants significantly reduced the interfacial tension (IFT) between Huabei crude oil and brine to ultra-low levels (<10 −3  mN/m) without any additives. Moreover, the ALGS surfactants exhibited excellent emulsifying abilities and superior salt resistance, also they effectively altered the wettability of quartz surfaces from oil-wet to water-wet. Adsorption studies showed that the ALGS surfactants had a low adsorption capacity on quartz sand, with an upper limit of less than 0.50 mg/g. In core flooding experiments, the ALGS surfactants could enhance the oil recovery by 21.15 wt% with the addition of polymer. These promising results indicate the potential of ALGS surfactants for use in chemical enhanced oil recovery (EOR).