Scalable production of hydrophobic and photo-thermal conversion bio-based 3D scaffold: Towards oil-water separation and continuous oil collection

Nowadays, the organic pollutants and oil contaminations caused by petroleum exploitation, industrial discharge, and sanitary wastewater are aggravating the water shortage, becoming a global problem. Even though a great number of advanced materials have been developed and devoted to solving these problems, the materials reported recently are usually at cost of sophisticated craft and expensive raw materials, which are unaffordable for underdeveloped countries and regions. Therefore, a facile, scalable as well as costly-available production approach is vital for oil-water separation materials. Using the natural skeleton structure of sugarcane residue, the bio-based 3D scaffold (F-DA-cane) with hydrophobicity and photo-thermal conversion capability is successfully prepared by a scalable and extremely simple craft, which uses polydopamine and fluorine-containing compound as functionalized coating. After two-step surface treatment process, the bio-based 3D scaffold can effectively absorb variety of oils and organic solvents. The absorption capability of F-DA-cane is up to 24.8 g/g (the maximum), which is almost 3 times higher than that of pure sugarcane (8.21 g/g). In order to achieve continuous oil-water separation, pumping-driven oil collection experiments is performed. The oil transport speed of F-DA-cane was significantly improved with the aid of its excellent photo-thermal conversion capability (254.5 L/m2h, more than twice of transport speed that obtained without light). These results indicated that these bio-based 3D scaffold could be used as an effective primary treatment method for organic solvents and oily wastewater. In conclusion, by taking advantage of common biowaste and simple coating technology, a facile, scalable as well as affordable production approach for preparing high-efficiency oil-water separation materials was successfully designed.