Degradable starch-based superhydrophobic cyrogel for efficient oil/water separation

The rapid expansion of the petroleum industry has led to a surge in oil spill incidents, the development of novel superhydrophobic absorbents for the efficient removal of oil spills has become increasingly imperative. In this study, a novel starch-based superhydrophobic composite absorbent was fabricated through a two-step process. Initially, potato starch was gelatinized and then freeze-dried to form a porous starch cryogel (SC). Subsequently, the SC was impregnated with carnauba wax (CW)/polydimethylsiloxane (PDMS) composite solution. After curing, the P-CW@SC with exceptional superhydrophobicity (contact angle = 154.0°) and superoleophilicity was developed. Furthermore, P-CW@SC exhibited excellent self-cleaning properties, anti-fouling efficacy, mechanical strength and chemical stability. Owing to its well-developed porosity, P-CW@SC demonstrated good oil absorption capacities (4.79–13.05 g/g). The selective hydrophobicity and lipophilicity of P-CW@SC enabled effective remediation of underwater oil spills and it could achieve oil-water separation efficiencies exceeding 95.59 % under dynamic conditions after 10 cycles. Upon 50 d of degradation testing in buffer solution, the weight loss rate of P-CW@SC weight reached 43.5 %. Considering its cost-effective raw material composition and simple preparation process, P-CW@SC holds significant potential application in the treatment of oily wastewater and oil spill remediation.