Nano graphite platelets/Cu (BDC) MOF coating on polyurethane sponge: A superhydrophobic self-extinguishing adsorbent for static and continuous oil/water separation

Abstract

The discharge of toxic organic solvents and industrial oil into water is one of the major problems that threaten marine ecology and human health. In this work, a flexible superhydrophobic/superoleophilic polyurethane (PU) sponge was modified by decorating Cu-benzene dicarboxylic acid metal-organic framework (Cu (BDC) MOF) as a flame retardant and nano graphite platelets (NGPs) as a superhydrophobic agent. These materials were attached to the sponge skeleton by poly (styrene-co-butyl acrylate). The PU-Cu (BDC)-NGPs sponge showed high thermal, mechanical, and chemical stability. Moreover, this composite possessed excellent oil/water separation efficiency. The prepared composite showed excellent superhydrophobicity with a water contact angle of 154° and possessed self-extinguishing properties with a limiting oxygen index (LOI) of 24.46%. The oil adsorption capacity at a static state and oil separation efficiency at a continuous oil/water separation process for PU-Cu (BDC)-NGPs sponge were 43.5–132 g/g and 96%, respectively. Moreover, PU-Cu (BDC)-NGPs sponge had excellent stability in harsh conditions and exhibited good compressibility and reusability. Overall, the Cu (BDC) MOF-NGPs coated PU sponge can be a highly efficient sorbent with durability and flame retardancy.