Synthesis of Honeycomb-Like Carbon Foam from Larch Sawdust as Efficient Absorbents for Oil Spills Cleanup and Recovery.

Hydrophobic oil absorbents with interconnected porous structure have been widely used in dealing with the pervasive environmental issue of oil spills. In this work, hydrophobic foams with 3D interconnected porous honeycomb structures of liquefied-larch-based polymer foam (LLB-PF) and its carbonized product liquefied-larch-based carbon foam (LLB-CF) was prepared from larch sawdust waste and used for oil and organics separation. The results revealed that the 3D interconnected and open-cell honeycomb structure of LLB-PF was formed simultaneously during self-foaming, which remained intact even after carbonization. The two ultralight foams, especially LLB-PF, exhibited remarkable oil/water selectivity. The foams exhibited efficient and rapid absorption capacities, not only for oils but also for organic solvents. LLB-PF and LLB-CF could absorb tetrachloromethane and epoxidized soybean oil up to 88 and 153 times their own weight, respectively. The recycle tests showed that LLB-PF and LLB-CF exhibited excellent absorption capacities even after five cycles, demonstrating an excellent cyclability. The high oil and organic solvent absorption performance along with the renewable and low-cost starting materials positions LLB-PF and LLB-CF foams as promising candidates with great potential for oil and organics cleanup.