Application of ceramic membranes for the separation of dye particles

This study reports the results of ultrafiltration experiments on model dye solutions containing anionic dyes and anionic surfactant. The ceramic membrane modules CeramINSIDE (TAMI Industries) of various cut-off values (1, 5, 8, 15, and 30 kDa) were used in the experiments. The suitability of ceramic membranes for the decolourization of dye solutions was evaluated. Seven anionic organic dyes of molecular weights ranging from 327 to 1084 Da were used in the tests. The anionic surface active agent (sodium dodecyl sulphate, SDS) was added to the dye solutions. The experiments were conducted at 0.03–0.1 MPa with the use of a laboratory and semi-pilot UF installation. The effect of the molecular weight of the dyes as well as the SDS presence in the separated solutions (in the range below the CMC) on the process efficiency was studied. It was found that membrane properties (permeability and dye separation factor) were almost identical for membrane modules of cut-off equal to 1, 5, and 8 kDa. For high-molecular-weight dyes above 600 Da retention amounted to 95–98% and was slightly influenced by the SDS presence in the dye solution. Ceramic membranes with a cut-off of 15 and 30 kDa exhibited insignificantly poorer properties.