Development of carbon nanotube/bacterial cellulose composite hydrogel membrane and its application for solar-driven interfacial evaporation

Solar-driven interfacial evaporation technology represents an effective approach to address water resource shortage. To develop an efficient solar interfacial evaporator, a carbon nanotube/bacterial cellulose (CNT/BC) composite hydrogel membrane was successfully fabricated in this study. Bacterial cellulose (BC), featuring a three-dimensional porous structure and excellent hydrophilicity, was utilized as the matrix, while carbon nanotubes (CNT) were incorporated as the light-absorbing material via physical adsorption and glutaraldehyde cross-linking treatment. The influence of CNT incorporation on the micro-morphology, mechanical property, hydrophilicity, photothermal conversion and solar evaporation performance of the composite hydrogel membrane were systematically investigated. The results demonstrated that the CNT/BC composite hydrogel membrane possessed robust mechanical stability, excellent water-transporting hydrophilicity and exceptional broadband photothermal conversion capabilities across full solar spectrum. The resultant composite membrane achieved a maximum evaporation rate of 1.82 kg·m⁻²·h⁻¹ under 1 standard sun illumination. Furthermore, it exhibited highly stable repeated evaporation performance and outstanding seawater desalination capability, reaching an evaporation rate of 1.69 kg·m⁻²·h⁻¹ in simulated seawater.