Stainless-steel-net-supported superhydrophobic COF coating for oil/water separation

This work reports the preparation and post-synthetic modification of COF named BTADHBD with perfluorooctyltriethoxysilane (POTS) to obtain a superhydrophobic COF coating. Through post-synthetic modification, the water contact angle (CA) of BTADHBD is increased from 83.7 degrees to 153.2 degrees without change of crystals morphology and structure. BTADHBD COF coating was prepared on the stainless steel net (SSN) through repeated growth, followed by post-synthetic modification using (+/-)-glycidol (Glc) and POTS to obtain the SSN-supported superhydrophobic BTADHBD@Glc@POTS coating with a water CA of 152.1 degrees. The superhydrophobic BTADHBD@Glc@POTS coating showed high water-resistance, self-cleaning property and oil/water separation performance using simply gravity as driving force. For various oil/water mixtures, the oil/water separation efficiency was always up to 99.5% with oil flux above 70 L/(m(2).s). For 50 successive cycles of oil/water separation, the high oil/water separation efficiency (above 99.5%) remained unchanged, which is very promising for oil/water separation.