Three-dimensional solar evaporation characteristics of PVDF@MWCNTs cotton composite membrane

In order to enhance solar evaporation efficiency and reduce cost, the study combined polyvinylidene fluoride (PVDF) and multi-walled carbon nanotubes (MWCNTs) with low-cost cotton fabrics. The PVDF@MWCNTs cotton composite films were prepared by non-solvent induced phase separation method, which demonstrates excellent photothermal conversion performance. The effects of structure (two-dimensional structure, three-dimensional structure), shape of three-dimensional evaporation structure (triangular, semicircular and rectangular), light intensity and brine concentration on the evaporation performance were experimentally investigated. The evaporation rate of the rectangular structure with a height of 15 mm is 3.083 kg/m 2 ·h and the evaporation efficiency is 0.938 under two light intensities and a seawater concentration of 4 wt%. The evaporation rate of the two-dimensional structure for the same material is basically in the range of 1.50 kg/m 2 ·h. The evaporation rate can be more than doubled in three-dimensional structures compared to two-dimensional structures.