Slippery Photothermal Membrane with Liquid Coating for Solar-Driven Membrane Distillation

Abstract

Membrane distillation (MD) has received increasing attention with great promise for desalination, but its application is still hindered by the high energy consumption and the limited lifespan of the membrane. Herein, novel slippery photothermal membrane with liquid coating was successfully fabricated by depositing photothermal carbon nanotubes (CNTs) on the surface of a nanofibrous mat and subsequently infusing with liquid polydimethylsiloxane (PDMS). Owing to the high photothermal efficiency of CNTs and accelerated mass transport across the nanofibrous mat, the as-prepared slippery membrane demonstrated a permeability of as high as 0.95 L·m-2·h-1 when assembled into a permeate-side-heated MD system, which equals to a relatively high energy efficiency of 63.5%. Furthermore, the membrane is highly effective in mitigating membrane scaling and wetting due to the presence of slippery liquid PDMS, whose high movability obstructs the adsorption of salt crystals on the surface. These results make the as-prepared slippery membrane a promising candidate for durable MD applications with high energy-efficiency.

Keywords: Membrane Distillation, liquid coating, photothermal, electrospinning, solar energy