Recent advances in the design and use of Pickering emulsions for wastewater treatment applications

Pickering emulsions have recently emerged as versatile systems capable of targeting many applications of wastewater treatment. The unique properties, which include high emulsion stability, easy preparation, low toxicity, and stimuli-responsiveness, pave the way for advances in common pollutant control processes. This review aims to provide a comprehensive overview on different aspects in the Pickering emulsion design focusing on the key structural relations and their implications in specific applications. The first section is dedicated to the critical parameters governing the Pickering emulsion type, droplet size and stability. Furthermore, a section describing methods for demulsification and particle recovery is included, in which various stimuli have been explored. Finally, the most potent applications of Pickering emulsions such as photocatalytic degradation, adsorption, extraction, and separation of common wastewater pollutants are presented and discussed with a great deal of attention towards the efficacy, current limitations, and future potential. Recognizing the rise of innovative Pickering emulsion solutions is expected to induce profound effects facilitating the technology transfer to industrial processes.