<p>With the development of new energy wind power, the disposal of decommissioned fan blades has become a new solid waste treatment problem. Herein, we report a high-value utilization method for the preparation of hydrophobic organic–inorganic hybrid aerogel by using waste fan blades in the presence of sodium alginate by a freeze-dry method, followed by a surface modification via polydimethylsiloxane to give a hydrophobic surface wettability (abbreviated as SA-FB@PDMS). Ethylene glycol was used to degrade the fan leaf powder, and the main polymer component epoxy resin was degraded into small molecule short polymers with a yield of 82%. The as-prepared SA-FB@PDMS aerogels have a low density of 0.09 g cm⁻³ with a high porosity of 95.14%. After being treated with polydimethylsiloxane (PDMS), a hydrophobic layer is formed on the surface of the as-prepared aerogels with a water contact angle reaches 122.58°. The thermal stability measurement shows that the as-prepared aerogel has a thermal robustness, i.e., its weight remains more than 95% at 222°C. The as-prepared aerogel shows a superior selective absorption for oils in water, it also possesses high oil adsorbability (the adsorption capacity for petroleum ether was measured to be 21 g g⁻¹). Moreover, the SA-FB@PDMS has reusability (the adsorption capacity is still 16.13 g g⁻¹ after five cycles). The findings of this study might provide a new strategy for the high-value utilization of waste fan blades for the practical application of oily wastewater treatment.</p>