Controlled production of eco-friendly emulsions using direct and premix membrane emulsification

Abstract

Eco-friendly O/W emulsions were produced by membrane emulsification using nickel membrane consisting of hexagonal arrays of cylindrical pores of 10 or 20μm diameter and 200μm spacing. The dispersed phase was a mixture of N,N-dimethyldecanamide (AMD-10TM) and d-limonene containing 0–35wt% AMD-10TM in the dispersed phase and the continuous aqueous phase was 3wt% polyoxyethylene glycerol fatty acid ester (Levenol® C-201). In direct membrane emulsification, the droplet-to-pore size ratio was 1.5–4.6 and the most uniform droplets were obtained with pure d-limonene at a stirrer speed of 620rpm, corresponding to the peak shear stress on the membrane surface of 7Pa. In premix membrane emulsification, the median droplet diameter decreased with increasing the transmembrane flux and was smaller than the pore size at the flux above 2000Lm−2h−1. The droplet size was 6μm after two passes through the membrane with a pore diameter of either 10 or 20μm. The viscosity of emulsions with 30wt% was not influenced by the shear rate but an emulsion with a dispersed phase content of 40wt% showed shear thinning behaviour and viscoelastic properties. The produced emulsions can be used as environmentally friendly matrices for incorporation of agrochemical actives.