Spent coffee ground (SCG), left over in coffee making, is the most abundant coffee byproduct, of which approximately 70% is made by cellulose and hemicellulose. Herein, we obtained a delignified SCG (D-SCG) by using an aqueous solution of 3 wt% NaOH for 1 h at 90 °C and then an aqueous solution of 3 wt% NaClO₂ buffered with acetic acid at pH 4.3 for 2 h at 90 °C, respectively. Next, we used the D-SCG to fabricate holocellulose nanofibers (HCNF) suspension by TEMPO-Mediated oxidation. Finally, HCNF suspension was manufactured into superhydrophobic foams for oil-water separation through freeze-drying and hydrophobic modification. The superhydrophobic foams showed good properties of oil absorption capacity (16 g/g), separation efficiency (98.5%) and continuous separation. This work presents a novel idea for the further application of SCG and provides an eco-friendly and sustainable oil absorbent material to solve oil spill.

咖啡生产中残留的咖啡残渣（SCG）是最丰富的咖啡副产品，其中约70％由纤维素和半纤维素制成。在这里，我们通过在90°C下使用3 wt％NaOH的水溶液1 h，然后使用3 wt％NaClO ₂的水溶液来获得脱木质素的SCG（D-SCG）。在90°C下分别用pH 4.3的乙酸缓冲2 h。接下来，我们使用D-SCG通过TEMPO介导的氧化来制备全纤维素纳米纤维（HCNF）悬浮液。最后，将HCNF悬浮液制成超疏水性泡沫，通过冷冻干燥和疏水改性将油水分离。超疏水性泡沫具有良好的吸油量（16 g / g），分离效率（98.5％）和连续分离性能。这项工作为SCG的进一步应用提出了一个新的想法，并提供了一种环保，可持续的吸油材料来解决漏油问题。