Continuous rotary membrane emulsification for the production of sustainable Pickering emulsions

A continuous rotary membrane emulsification (cRME) system, allowing the decoupling of droplet generation from continuous phase (CP) flowrate, is presented here for the first time. The decoupling results in higher productivity and greater control compared to traditional crossflow and rotational membrane emulsification processes. A design of experiment (DoE) investigated the influence on droplet formation of CP flow, membrane rotational speed and emulsion composition, using a Pickering emulsion consisting of 1 wt% keratin solution and varying concentrations of oxidised cellulose nanofibrils. Experiments showed that CP flowrate had a negligible effect on droplet diameters in a wide range (between 78 and 241 µm), with uniformity index as low as 0.14 for optimal membrane rotational speeds and different oxidised cellulose nanofibrils (OCNF) concentration. cRME has the potential to overcome low emulsion concentration limitations of continuous membrane emulsification systems, paving the way to significantly increase the productivity and application in personal care, food and drugs industries.