Solar-Driven Dehydration and Purification of Oily Pollutants with a Multifunctional Biomass-based Carbon Aerogel: A Potential Step Towards Carbon Reduction

Efficient disposal of oily water pollution and oily sludge (OS) production with low energy demand has garnered significant attention for the low carbon transition of the petroleum industry. How to overcome the hardships from severe emulsion and interaction with soil minerals in emulsion–soil (OS) is a significant challenge with the prospective opportunities of solar energy substitution. This paper proposed the solar-driven photothermal conversion technology for efficient dehydration of OS and purification of oily water using a multifunctional material. A biomass-based carbon aerogel (BCA-600) with a porous three-dimensional (3D) structure and photothermal conversion characteristics was synthesized. Interestingly, this carbon aerogel possessed adjustable surface wettability, enabling it to adsorb high viscosity crude oil on the water surface (4.28 g·g −1 ) and achieve demulsification–separation in water-in-oil emulsions (97.28%) with the assistance of solar irradiation. Accordingly, the synergistic action of solar heating and separation–adsorption of emulsion by BCA-600 contributed to the efficient photothermal dehydration for both OS and emulsion. The highest dehydration efficiency for OS reached 90.68% with the OS/BCA-600 mass ratio of 10:2. Moreover, BCA-600 could remain in the dehydrated OS without separation to participate in the following pyrolysis with enhanced effects by confined-catalytic cracking, achieving a “one stone, two birds” effect. Overall, the solar photothermal approach exhibits significant potential for treating oily pollutants, reducing carbon emissions by more than 100 times compared to traditional thermal methods. This could be a strong push for the low carbon transition of the petroleum industry.