Design of Nanocellulose Fibrils Containing Lignin Segment (L-NCF) for Producing Stable Liquid Foams as “Green” Flooding Agents for Oil Recovery

Foam stability is a crucial consideration in the view of its numerous applications. Herein, a series of nanocellulose fibrils containing lignin segment (L-NCF) was designed and then utilized for interfacial stabilization of liquid foams for eco-friendly oil recovery applications. The ability to form foams and their stability at bulk scale and bubble scale were thoroughly investigated using a foam scanner. Liquid drainage rate, bubble rupture, interfacial dilational viscoelasticity, and bubble transport in porous media were studied as a function of lignin content. We observed that in a vertical column the addition of L-NCF significantly mitigated the drainage of the liquid foams. The foam volume stability (FVS) index indicated that the stability of the foams in the presence of L-NCF was up to five times higher than that of surfactant-only foam. The hydrophobic interaction between the surfactant (mixture of alkyl polyglycoside (APG) and anion surfactant alpha olefin sulfonate (AOS)) and L-NCF (lignin segment) constructed an elastic interface for the foams, which notably protected the liquid foams from coarsening and coalescence. The L-NCF stabilized foams can appropriately transport in porous media without the plugging issue, during which great differential pressures are simultaneously built up as a result of the yielded elastic interface. It is believed that nanocellulose is very promising in the oil production industry as a green alterative to synthetic chemicals.