Rapid self-assembly of lignin and dopamine to synthesis acid-base resistant superhydrophobic coating for oil-water separation

• Published in: Colloids and surfaces. A, Physicochemical and engineering aspects Physicochemical and engineering aspects, 2025-01, Vol.704, p.135513, Article 135513
• Main Authors: Wang, Liyunlong, Guo, Zongwei, Yang, Guihua, Ji, Xingxiang, Lyu, Gaojin
• Format: Article
• Language: English
• Subjects: Acid-base resistance; Dopamine; Lignin; Oil-water separation; Self-assembly
• ISSN: 0927-7757
• DOI: 10.1016/j.colsurfa.2024.135513

Industrial lignin has a wide range of applications in superhydrophobic materials despite its low chemical reactivity due to the low hydroxyl content. To enhance its chemical reaction activity, surface functionalization of lignin was performed to improve the hydroxyl content. Herein, inspired by the similarity of lignin aromatic structure unit and dopamine structure, a superhydrophobic coating was synthesized by rapid self-assembled of lignin and dopamine composite particles. When applied to paper substrates, this lignin-based coating exhibited excellent separation and recovery efficiency of oil-water mixtures, maintaining separation efficiency of 93.5 % and oil flux up to 906.35 L m−2 h−1 after 50 cycles. The coated paper also demonstrated favorable fractionation efficiency (92.4 %) and oil flux (192.58 L m−2 h−1) for oil-in-water emulsions. More importantly, the coated paper presented outstanding stability and cycle performance under the strong acid-base conditions due to its cauliflower-like micro- and nano-bumped surface morphology with porous channels in the coating. Additionally, the excellent mechanical durability, coating stability, self-cleaning, UV aging properties, and substrate applicability were also elucidated to provide a strong guarantee for applications in harsh environments. To sum up, this stable and eco-friendly superhydrophobic coating would provide a new pathway for the high value utilization of lignin waste and sustainable development of functional material. [Display omitted] •The lignin surface was functionalized to fabricate superhydrophobic coating.•The coating exhibited significant superhydrophobic stability and durability.•A superior flux of 906.35 L m−2 h−1 for oil-water mixtures separation was obtained.•The coated paper could effectively separate the highly stable water-in-oil emulsion.•Excellent separation and recovery were achieved in the strong acid-base conditions.