Solar interfacial evaporator based on robust aligned channels bacterial cellulose aerogels for wastewater treatment

Solar-driven interfacial evaporation (SDIE) has shown great potential for seawater desalination and wastewater treatment. In this context, we report the development of a composite aerogel material, termed BCAM, which is synthesized from bacterial cellulose, agar powder, and glutaraldehyde, with the addition of MXene as a photothermal material. The two active aldehyde groups (-CHO) of glutaraldehyde undergo a condensation reaction with the hydroxyl groups (-OH) in bacterial cellulose and agar powder, promoting crosslinking between the molecular chains and forming a composite material with directional channel structures. This material exhibits a rich porous structure, excellent mechanical properties, and superhydrophilic characteristics, and is shaped using a gradient cooling method. The incorporation of MXene enhances the light absorption of BCAM (up to 95.6 %), resulting in an evaporation rate of 1.78 kg·m −2 ·h −1 , while the evaporation rate of 3D BCAM reaches 3.43 kg·m −2 ·h −1 . After seawater desalination, BCAM achieved a removal efficiency of over 99 % for major ions in seawater. Furthermore, in practical industrial wastewater, the evaporation rate of the 3D BCAM evaporator reaches 2.8 kg·m −2 ·h −1 , and BCAM maintains its structural integrity after being immersed for 24 h under various acidic conditions (pH:1–5). Overall, these findings demonstrate the substantial practical application potential of BCAM in SDIE technologies.