Detergency and Its Implications for Oil Emulsion Sieving and Separation

Collagen Fiber-Based Advanced Separation Materials: Recent Developments and Future Perspectives

Separation plays a critical role in a broad range of industrial applications. Developing advanced separation materials is of great significance for the future development of separation technology. Collagen fibers (CFs), the typical structural proteins, exhibit unique structural hierarchy, amphiphilic wettability, and versatile chemical reactivity. These distinctive properties provide infinite possibilities for the rational design of advanced separation materials. During the past 2 decades, many progressive achievements in the development of CFs-derived advanced separation materials have been witnessed already. Herein, the CFs-based separation materials are focused on and the recent progresses in this topic are reviewed. CFs widely existing in animal skins display unique hierarchically fibrous structure, amphiphilicity-enabled surface wetting behaviors, multi-functionality guaranteed covalent/non-covalent reaction versatility. These outstanding merits of CFs bring great opportunities for realizing rational design of a variety of advanced separation materials that were capable of achieving high-performance separations to diverse specific targets, including oily pollutants, natural products, metal ions, anionic contaminants and proteins, etc. Besides, the important issues for the further development of CFs-based advanced separation materials are also discussed.

Highly-efficient, Rapid and continuous separation of surfactant-stabilized Oil/Water emulsions by selective under-liquid adhering emulsified droplets

Anti-adhesion is considered to be the basis for oil/water separation. However, this principle may not the superior choice for surfactant-stabilized oil/water emulsions owing to the inevitable adhesion of surfactant on the membrane, resulting in further adhesion of emulsified droplets and therefore attenuation in separation performance. Herein, we demonstrated a novel separation strategy for surfactant-stabilized oil/water emulsions by exploiting rather than preventing adhesion. A modified filter paper (mFP) with strong under-liquid adhesion to emulsified droplets was prepared, endowing it excellent separation performance for both surfactant-stabilized and surfactant free emulsions with very high separation efficiency (up to 99.9 %). Furthermore, the Random layer stacked scraps of mFP (RLS-mFP) were used to construct the separation device, which provided a labyrinthine but unobstructed flow path for emulsion because of the randomly stacked form and relatively large interspace among mFP scraps. The RLS-mFP has excellent separation performance with the separation flux for surfactant-stabilized oil-in-water and water-in-oil emulsions achieving 1035 and 3570 L m^-2 h^-1 respectively only under gravity. After 1-hour continuous separation, both flux and separation efficiency of RLS-mFP showed almost no decline comparing to initial flux for surfactant-stabilized emulsions. Meanwhile, the mFP could be easily recycled by rinsing and reused at least 50 times without sacrificing separation performance.