Development of highly efficient, renewable and durable alginate composite aerogels for oil/water separation

To valorize the naturally abundant biomass, bio-composites made of biomass and functional nano-materials have attracted a great deal of attention. By incorporating alginate with TiO₂/RGO nanocomposites, TiO₂/RGO/Alginate composite (TRGA) aerogels are fabricated via a facile freeze-drying method. TiO₂/RGO nanocomposites can effectively improve the surface roughness and mechanical performance of alginate-based matrix, and provide the aerogels with light-driven self-cleaning ability. Without further chemical modification, the as-fabricated TRGA aerogel shows: i) collective underwater superoleophobicity (θ_oil > 150° for various oils), ii) effective oil/water separation performance (9.76 L·m⁻²·s⁻¹ water permeate flux and 99.96% separation efficiency) and iii) excellent light-induced recyclability. With light-driven self-cleaning ability, the continuously deteriorated separation performance of aerogel can be easily renewed, and maintain an effective oil/water separation performance even after 120 cycles. Benefiting from its facile fabrication and excellent properties, the developed aerogel can be a promising candidate for practical oil/water separation in marine oil spill clean-up applications.