Fig. 4: Desalination performance of the nanofilament-coated membranes.

a Schematic of the air gap membrane distillation (AGMD) testing system. b 3D schematic depicting the design of the AGMD module. A membrane with an effective area of 19 cm² was mounted between the hot feed flow channel and condensation chamber. An acrylic spacer is inserted to create the required air gap. The support mesh helps to hold the membrane in a planar shape and reduce the membrane deformation due to transmembrane pressure difference. c Experimental steady-state distillation flux as a function of distillate conductivity for the nanofilament-coated PES, commercial PE and PTFE membranes in 12 h AGMD desalination tests. Temperatures of feed and cooling water were 80 and 20 °C, respectively. Flow rates of feed and cooling water were 1.5 and 2 L min⁻¹, respectively. Error bars indicate standard deviation (n = 5). d Time evolution of thermal efficiency for the NF-PES-8, PE-0.2, and PTFE-0.2 membranes in 12 h AGMD desalination. The operating conditions are the same as c. The error bands indicate the propagation of error associated with the fluid inlet and outlet temperatures, flow rate, and distillate weight measurement.