• 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 Guha, Kripa K Varanasi, Current Opinion in Colloid & Interface Science