As global industrialization accelerates, the discharge of oily wastewater has become a serious environmental issue. Melamine sponge (MS) has garnered significant interest for oil-water separation due to their exceptional porosity, surface amino functionality, and cost-effectiveness. However, hydrophobic modification technology for sponges still faces challenges of complexity and high cost. To address this issue, a straightforward, room-temperature, one-pot strategy using a low-cost linear terphenyl ligand is reported for fabricating a superhydrophobic melamine sponge (F-COPs@MS) via an in-situ Schiff base reaction between 2,3,5,6-tetrafluoroterephthalaldehyde (TFTD) and 1,1':4',1''-terphenyl-4,4''-diamine (TPDA), which forms a uniform fluorinated covalent organic polymers (F-COPs) coating. The resulting F-COPs@MS exhibits superhydrophobicity with a water contact angle (WCA) of 160.5 ± 1.8°, outstanding adsorption capacity for oils and organic solvents (66-145 g g⁻¹), and remarkable recyclability (98% after 50 cycles). Furthermore, it achieves high separation efficiency (> 95%) for various oil-water mixtures under both gravity-driven and continuous pump-driven systems, highlighting its practical utility. These outstanding properties stem primarily from the low surface energy and hierarchical micro- and nano-roughness imparted by the F‑COPs coating. Importantly, the F-COPs@MS sponge maintains strong structural and chemical stability in acidic (1.0 M HCl), alkaline (1.0 M NaOH), and saline (1.0 M NaCl) environments, along with enhanced flame retardancy. Given its simple preparation and excellent performance, F-COPs@MS is a highly promising material for the practical remediation of oily wastewater.
Sun et al. (Fri,) studied this question.