A multi-layer interfacial evaporator system for efficient freshwater production utilizing PANI-modified membrane, loofah sponge, and foam

Solar-driven interfacial steam generation (SDIE) system has emerged as an innovative technology for fresh water production, especially in desalination. Therefore, efficient, reusable, and environmentally sustainable SDIE evaporators are being developed. In this study, a novel multi-layer interfacial evaporator was constructed by combining a polyaniline-modified (PANI-modified) membrane, a loofah sponge, and foam. In this system, the PANI-modified membrane, acting as a photothermal layer, was synthesized via in-situ polymerization on an electrospun nanofiber composite membrane composed of carbonized loofah (CL) powder and polyacrylonitrile (PAN), achieving higher efficiency for fresh water production. In addition, the loofah sponge served as a connecting layer due to its net-like structure, anchoring the upper photothermal layer to the lower foam supporting layer, thereby insulating them from each other. Finally, the support foam layer was formed in-situ with Polyamide 6 (PA6) doped with bamboo charcoal (BC) at the bottom of the connecting layer. The as obtained PA6-BC supporting layer provided functions such as structural support, heat insulation, and contaminant adsorption. This system achieved a deionized water evaporation rate of 1.799 kg m −2 h −1 under 1 sun illumination, and 1.675 kg m −2 h −1 in 3.5 wt.% NaCl solution. Moreover, the system exhibited a high adsorption rate of methylene blue (MB) dye pollutant. The multi-layer interface evaporator also demonstrated excellent salt resistance and stability. These features showcase the novelty of the designed multi-layer interface evaporator and demonstrate the feasibility of applying a multi-layer interface evaporator in photothermal evaporation water treatment.