Self-floating, monolithic, and aligned phenolic carbon aerogels from coal tar for solar-driven evaporation

[Display omitted] •Self-floating and aligned phenolic carbon aerogels with high light absorption were fabricated from coal tar.•A high evaporation rate of 1.81 kg m-2h−1 and energy efficiency of 93.4 % can be obtained.•More than 99% salt ions and heavy metal ions can be removed by the aerogels. Polycyclic aromatics in low-temperature coal tar (LTCT) make it to be notorious and it is urgent to develop value-added utilization technologies of LTCT. On the other hand, solar-driven evaporation has attracted much attention owing to high energy efficiency and zero carbon emission. However, it is limited to expensive photothermal materials and external supports. In this paper, self-floating and monolithic coal tar-based phenolic carbon aerogels (CPCAs) were facilely constructed. Polycyclic aromatics in LTCT endow CPCAs strong light absorption and photothermal conversion superior to carbon nano tube. Additionally, CPCAs possess fast water transportation owing to their excellent hydrophilicity and aligned hierarchical channels. Moreover, water molecular states can be easily regulated, thus reducing evaporation enthalpy. Combining with these characteristics of CPCAs, water evaporation rate and energy efficiency can reach to as high as 1.81 kg m-2h−1 and 93.4 %, respectively. In addition, high compressive strength, good salt-tolerance, durability, and versatility facilitate CPCAs practical applications.