Via Separations, a membrane start-up in Watertown, Massachusetts, has raised $38 million in a series B financing round led by NGP Energy Technology Partners. Via, one of C&EN’s 10 Start-Ups to Watch in 2019, is developing graphene oxide separation materials. It is targeting industries in which filtration can replace energy-intensive thermal separations. One example is removing solids from the black liquor that results from papermaking. Via will use the money it raised to deploy its system in the pulp and paper sector and adapt it for chemical production.