Ultrahigh-water-flux desalination on graphdiyne membranes

Membrane desalination is an emerging technology that shows promise for producing freshwater from saline waters. However, most membranes are challenged by low freshwater flux, impacting the water productivity, energy efficiency and membrane usage. Here we present the submicrometre-thick and nanopore-structured graphdiyne membranes on porous Cu hollow fibres. We accomplish nearly perfect NaCl rejections (>99.9%) and ultrahigh water permeabilities reaching ~700 l m⁻² h⁻¹, which are approximately 1–3 orders of magnitude higher than those of commercial polymeric membranes, in vacuum membrane distillation of a 3.5 wt% NaCl solution. Membrane stability is demonstrated by feeding hypersaline waters, real seawater and pollutant-containing waters. The resultant interfacial and microstructural properties of the membranes combine the interfacial ion sieving effect with vapour-transport capability to enable complete salt exclusion and accelerate the water flux. Experimental and theoretical studies have revealed that interfacial transport between graphdiyne interlayers increases the water flux by orders of magnitude relative to transport through intralayer pores.