Can a molecular sponge clean the water we drink?

Imagine a material so porous that, if you unfolded the internal surface of a single gram, you would cover an entire tennis court. It exists, and it is called a MOF: a metal-organic framework.

During my research I became fascinated by one very specific question: can we design those cavities to capture exactly the pollutants that worry us most? In one of our studies we functionalized an iron-based MOF (MIL-100-Fe) with sulfonic groups to capture diclofenac —a very common anti-inflammatory drug— from water.

Conventional water treatments are good at removing the obvious, but a family of substances (drug residues, pesticides) appear in such tiny concentrations that they slip through standard filters. These are the emerging pollutants, and this is exactly where materials chemistry has something to say.

The beauty of MOFs is that we can tune the size of their pores and the chemistry of their walls so they prefer to capture one specific molecule. Step by step, we are getting closer to smart materials working inside our water treatment plants.