A reusable, biomass-derived, and pH-responsive collagen fiber based oil absorbent material for effective separation of oil-in-water emulsions

Absorbent material plays an increasingly important role in oil-water separation due to its high-efficiency, cost-effective and environment-friendly. Herein, amino-functionalized biomass-derived collagen fiber matrix (defined as A-CFM) with dodecyl hydrocarbon chains was prepared as oil-water separation adsorbent material by in-situ graft copolymerization of 2-(dimethylamino)ethyl methacrylate (DMAEMA) and glycidyl methacrylate (GMA). The A-CFM possesses favorable porosity, appropriate pore size and excellent hydrophobicity, which exhibits high separation efficiency (similar to 99.90%) for whether surfactant-free emulsions or surfactant stabilized emulsions, even after three cycles. In addition, the tunable wettability of A-CFM can be achieved by altering the pH value, which not only imparts outstanding recycling performance, but also improves the antifouling performance to A-CFM absorbent material. Furthermore, the analysis of oil-water separation mechanism indicates that hydrophobicity and capillary force, especially electrostatic interaction (electrostatic attraction/repulsion), play a key role in separating emulsions stabilized by ionic surfactant. Our findings expend the knowledge of oil-in-water emulsion separation, as well as pave a new way for developing high-performance adsorbent materials with good application prospects in oil-water emulsion separation.

Automated summary

The A-CFM, prepared through in-situ graft copolymerization, demonstrates high separation efficiency for both surfactant-free and surfactant-stabilized emulsions even after multiple cycles. The tunable wettability of A-CFM by altering pH value not only enhances recycling performance but also improves antifouling properties. Additionally, the analysis of oil-water separation mechanism indicates that hydrophobicity, capillary force, and electrostatic interactions play key roles in separating emulsions stabilized by ionic surfactants.