The main goal of nanotechnology is to study and apply the properties of structures measuring less than a few tens of nanometres across. In the collective imaginary, this often translates into the study of single nanostructures or a small number of them. If we take graphene, for example, a typical nanotechnology study concerns the development of electronic components based on one or more sheets of this carbon material.

For materials scientists and engineers, however, nanotechnology consists more in using the properties of individual nanostructures to develop new materials with improved performance. Going back to the example of graphene, or even better its derivative graphene oxide, realizing macroscopic porous structures is particularly promising for applications that require materials with large surface area combined with the facility of chemical modification, for example energy storage or water and air filtering. In a Review published in this issue, Nathalie Tufenkji and co-authors overview the efforts made in the past few years to demonstrate the potential of large structures composed of graphene and graphene oxide sheets for environmental applications.

The article covers applications of macroscopic graphene and graphene oxide structures for removal of contaminants from water, for desalination, for carbon dioxide capture, for air pollution treatment and for antimicrobial applications. Beyond overviewing the potential of graphene materials for these applications as demonstrated by proof of principle experiments, the real value of such an article lies in two other aspects. First, it explores the connection between the properties and the performance of the materials. Understanding this relationship is essential for the successful development of nanotechnology more generally, but too often it is neglected. Second, it points out the information that is currently lacking and that will be essential if these structures are intended to compete with current industry standards such as activated carbon. For example, for water cleaning applications, it will be necessary to explore the ability of graphene-derived macrostructures to remove organic pollutants or other emerging contaminants such as those connected to pharmaceutical compounds. Most importantly, the article stresses the need to move from relatively simple laboratory-scale studies to more complex and more realistic conditions, which is becoming a generally recognized necessity for environmental nanotechnology studies.