Multifunctional superhydrophobic sugarcane bagasse capable of efficiently separating oil-water mixtures and degrading MB.

Biodegradable and low-cost superhydrophobic absorption materials are still urgently required for the removal of organic compounds from sewage. In this study, sugarcane bagasse (SCB), an abundant and readily available byproduct from sugarcane industries, was used as substrate to fabricate the superhydrophobic adsorbent through a facile dip-coating technique. Firstly, β-FeOOH particles were in-situ grown on the SCB surface, which was further decorated with SiO particles. Next, the modified SCB were coated with benzoxazine based on cardanol and dodecylamine (CD) followed by a thermal curing to obtain a superhydrophobic SCB (PC-D/β-FeOOH@SiO/SCB) with a water contact angle (WCA) of 154°. PC-D/β-FeOOH@SiO/SCB not only exhibited excellent oil absorption capacities in the range of 11.8 to 22.6 g/g for various organic solvents and oils, but also could successfully separate immiscible oil-water mixtures and emulsions with a separation efficiency of over 99.1 %. After 30 cycles of use, the absorption capacity of the modified SCB only displayed a slight decrease and its separation efficiencies for immiscible oil-water mixture, water-in-oil and oil-in-water emulsions are all more than 99.2 %, meanwhile, all these repeatedly used SCB still maintained a superhydrophobicity, demonstrating an outstanding reusability. Moreover, the WCA of PC-D/β-FeOOH@SiO/SCB was still higher than 150 after 48 h of immersion in HCl, NaOH and NaCl solutions, exhibiting a satisfactory chemical stability. Besides, the prepared SCB also possessed a high photocatalytic degradation activity to methylene blue. Therefore, this work not only provides a sustainable and cheap superhydrophobic absorbent for wastewater treatment, but also presents a route for the better utilization of SCB.