Preparation of superhydrophobic/superhydrophilic sodium alginate aerogels for efficient oil absorption

The advanced treatment and resource utilization of oily wastewater are of great significance to solve water shortages and realize carbon peaking and carbon neutrality goals. The construction of biomass-based superwetting surfaces with recyclability, non-toxicity, and degradability is considered to be a promising strategy to overcome the unavoidable bottlenecks of “secondary pollution” and high costs in the current design of superhydrophobic structures. In this work, a strategy for preparing multifunctional sodium alginate (SA) superhydrophobic surfaces was proposed. By virtue of the synergistic mechanism of SA, SiO2 nanoparticles, pseudo-polyrotaxane and methyltrimethoxysilane, a superhydrophobic sponge with a green biomass-based carrier was prepared, which was constructed using a superhydrophobic elastomer with a three-dimensional network. The modified SA aerogel has a contact angle of 155.2° and even exhibits strong corrosion resistance in harsh environments with a water contact angle greater than 155°. Notably, the increase of green biomass-based materials provides a promising and sustainable development path for the preparation of hydrophobic substrates.