Separation and concentration of cationic surfactant solutions with the use of ceramic modules

This paper presents the findings of experimental research on employing ultrafiltration and microfiltration ceramic modules (150 kDa, 0.14 μm, 0.45 μm) for removal and concentration of the cationic surfactant Tequat LC90i (TEAQ) from water solutions. The filtration tests were performed at a semi-pilot installation in a crossflow regime. The feed solution parameters (surfactant concentration, pH of the treated solution, the presence of inorganic salt), and process conditions (transmembrane pressure and linear velocity) on the membrane filtration efficiency were evaluated. In all tests, very satisfactory TEAQ retention coefficients (in the range of 70–95) have been achieved. However, surfactant fouling occurred resulting in deterioration of the permeability of the modules. Modules characterized by the pore sizes greater than the size of surfactant particles (i.e., 0.45 μm modules) proved to be the most fouling resistant ones. It was also proven that process performance at high linear flow velocity can efficiently reduce the intensity of membrane pore blocking.