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 (θoil > 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. TiO2/RGO/Alginate aerogels are fabricated via a freeze-drying combined ionic cross-linking method, the bio-composite aerogel is of nano-scale surface roughness, photocatalytic renewability, and effective oil/water separation performance. [Display omitted] •High performance TiO2/RGO/Alginate bio-aerogels are fabricated via a facile method.•TiO2/RGO nanocomposites can improve the surface and network structure of aerogels.•The TRGA aerogels show excellent oil/water separation performance and recyclability.•The deteriorated TRGA aerogels can be easily renewed by solar irradiation.•The bio-composite aerogel is a promising candidate for oily wastewater treatment.