Functionalized carbon fiber felts with selective superwettability and fire retardancy: Designed for efficient oil/water separation

Advanced materials with special wettability have attracted wide attention for their potential application in environmental remediation, catalysis or superfluid now. This contribution reports a straightforward and low-cost high-performance methodology for the preparation of carbon fiber felt with selective superwettability and fire resistance. The functionalized carbon fiber felt (UV-CFF) is prepared by a simple UV-O3 treatment process for the enhancement of its superamphiphilicity in air and superoleophobicity underwater, the underwater contact angles of the organics is over 155°. Subsequently, surface functionalization of UV-CFF with 4-trifluoromethyldiazobenzene hydrochloride is carried out. Its surface could be effectively modified with aryl and carbon–fluorine groups through diazonium chemistry to obtain a superhydrophobic carbon fiber felt (f-CFF) with water contact angle of 152.5 ± 0.8°. Both of the UV-CFF and f-CFF samples exhibits effective oil/water separation behavior. Benefiting from the selective superwettability, the two samples provide the potential to selectively eliminate underwater oily phases and emulsions under different hydraulic pressures. For UV-CFF, its rejection of oil reaches 100%, and the rejection of water for f-CFF reaches 98.21 ± 0.7%. The adsorption capacities of different types of organic solvents for f-CFF is 4–14 g g−1, and its demulsification capacity can reach to 99.9%. Due to its corrosion resistance, facile fabrication technique, cycle stability and flame retardancy, the carbon felts hold great promise for potential applications in environmental remediation of water.