• Separation of nanoscale emulsion is extremely difficult due to small droplet sizes.

• Nanoscale emulsions pose a significant environmental risk.

• Recent approaches include novel membranes, chemicals, and magnetic nanoparticles.

• Techniques suffer from low flux, low separation efficiency, and environmental risks.

• Research into scalable, green techniques is needed to meet industry demands.

Paper: Ingrid GuhaKripa K Varanasi, Current Opinion in Colloid & Interface Science