Membraneless water filtration using CO2

Synopsis

In 2015, UNICEF estimated that 663 million people worldwide still lacked access to improved or protected water sources, and published a report showing that despite significant improvements between 1990-2015, a lot of work remains to be done [1]. Significant drawbacks to conventional purification techniques that use a porous membrane, such as microfiltration and reverse osmosis, motivate the development of a membraneless alternative [2]. In this work, Shin et al propose and demonstrate a proof-of-principle microfluidic device that uses the dissolution of CO2 into water to create ion concentration gradients that can be used to separate particles via diffusiophoresis [2]. Their work demonstrates a potential water purification technology which is scalable and avoids the drawbacks of conventional alternatives [2].

[1] UNICEF. Progress on Sanitation And Drinking Water: 2015 Update and MDG Assessment (World Health Organization, 2015).
[2] Shin, S. et al. Membraneless water filtration using CO2. Nat. Commun. 8, 15181 doi:10.1038/ncomms15181 (2017).