Highly elastic aerogel derived from spent coffee grounds as oil removal adsorbent

In the face of increasing environmental pollution, aerogels have emerged as valuable materials for potential oil/water separation. However, many of the currently developed aerogels have unsatisfactory compressibility, high cost and a single hydrophobic modification method, which limits larger-scale application. In this work, a type of aerogel with compressible, inexpensive, and fully biodegradable features was designed via a novel zirconium chloride modification strategy. Typically, a series of aerogels (HCSW-1, HCSW-2, and HCSW-3) were readily prepared from a mixture of spent coffee grounds, waste paper and sodium alginate. The prepared aerogels exhibited good elasticity, low density (0.024 g cm −3 ), high porosity (98.3%), efficient oil/water separation and good oil uptake (23-44 times of its weight). In addition, the as-prepared aerogels can be easily recycled several times, thus meeting the demand of actual oil/water separation. Such prominent results provide a new perspective for the development of efficient hydrophobic aerogels in the treatment of offshore oil spills and industrial wastewater.