Title : Lignin and derivatives as dispersant and emulsifier for pigment and crude oil
Abstract:
Lignin is a natural, abundant, renewable and green material. Copper phthalocyanine (CuPc) was used as a model pigment. Copper phthalocyanine (CuPc) is a widely used organic blue pigment with color brilliance, light fastness, and low cost. However, its poor dispersibility in aqueous solutions limits the water-borne application. Lignin’s aromatic hydrophobic polymer core and hydrophilic substitute structure makes it a potential good dispersant. Lignin carboxylic acid (−COOH) and amine (−NH2) derivaties were synthesized and investigated as dispersant for CuPc in aqueous solutions. The results showed that lignin amine derivative gave the best suspension stability of CuPc. The dispersion is correlated to zeta potential, particle size and adsorption on pigment surface. Lignins derivatives gave the best CuPc dispersion in acrylic paint formulations, enhancing the tinting strength of CuPc to 111%. Additionally, nanoparticles (LNPs) were prepared using an eco-friendly anti-solvent precipitation process from an aqueous alkali lignin solution, with hydrochloride acid serving as the anti-solvent. LNPs were used as Pickering emulsifier of crude oil. The crude oil with asphaltene is difficulty to wash off from hard surface with aqueous surfactant. The LNPs was used to wash crude oil from hard surface. The performance is correlated to its physical chemical properties such as wettability alternation, zeta potential, interfacial tension, and emulsion stability. The results showed that LNPs achieved excellent oil emulsification removal (91%) from hard surfaces, primarily due to the alteration of wettability of surfaces. The research provides new insights into the application of the eco-friendly lignin materials as dispersant and emulsifier.
