GEORGE ALEXANDRU POPA, DANIELA FLORENTINA ENACHE (POPA), SZIDONIA KATALIN TANCZOS, ADRIAN CIOCANEA ULTRAFILTRATION OF AQUEOUS SOLUTIONS OF FOOD DYE USING POLYMERIC MEMBRANES PREPARED WITH SURFACTANTS The objective of the study is the low-pressure membrane process for treating aqueous solutions containing synthetic food dye (E104 – quinoline yellow). Dye concentration used was 10% (equivalent to 100g/m3). The pressures used in the ultrafiltration process were 0.1, 0.2 and 0.3 MPa. Experiments were performed in dead - end instalations in which the effectiveness of the polysulfone - alkylbenzyldimethylammonium chloride (PSU-ABDMA) and polysulfone - N-dodecylpyridinium chloride (PSU - NDPCl) were tested. The efficiency of these membranes has been proved by calculating the permeate flow and the retention. Analyzing the experimental data, it was found that for the polysulfone-alkylbenzyldimethylammonium chloride composite membrane the degree of retention is completely different, with high values being obtained for low pressures and low values for high pressures used.