Enhancement of Crossflow Ultrafiltration for the Treatment of Stabilized Oily Emulsions

Abstract

Separation of stabilized oil droplets was conducted via crossflow ultrafiltration (UF) in a laboratory scale. A plate-and-frame membrane module was operated with two commercial organic membranes: regenerated cellulose (RC) and polyethersulfone (PES). Cutting oil was used for preparing oil-in-water emulsions. Membrane fluxes were observed under varied oil concentrations and transmembrane pressures (TMP). It was found that UF provided oil rejection more than 97% for all operational cases. The optimal operating condition was found at the oil concentration less than 1 g/L and TMP of 2−3 bar. As predicted by Hermia's model, the dominant fouling mechanism was the cake formation upon the membrane surface. The fouled membrane was effectively regenerated by the sequential cleaning of 0.5N-SDS, 0.1N-NaOH, and 0.01N-EDTA, respectively. The cleaned membrane was acquired with 96% flux recovery (FR) and 55% resistance removal (RR). Additionally, an integration of UF and pretreatments (i.e., chemical destabilization and coalescence) could improve flux decline of the membrane, while satisfactory discharge quality was achieved.

Long-Term Performance of Ultrafiltration Membranes: Corrosion Fouling Aspect

“…It is well known that the separation of oily emulsions can be successfully performed by membrane processes. Indeed, the ultrafiltration (UF) technique was demonstrated to be an efficient and effective method for separating oil-in-water emulsions with the use of both ceramic and polymeric membranes [ 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 ].…”