Simultaneous removal of phenols and Cr3+ using micellar-enhanced ultrafiltration process

The removal of phenol, p-cresol, xylenol and Cr3+ ions in simultaneous micellar-enhanced ultrafiltration process was examined. A cationic (CTAB) and anionic surfactant are selected as molecules that are able to create micelles. The rejection coefficients for solutes and surfactants were determined experimentally. The ultrafiltration process was carried out using polysulphone membrane (20 kDa) in cross-flow and steady-state conditions. It was observed that rejection coefficients of solutes increased with the increase of feed CTAB and SDS concentration. The highest rejection coefficients for the most hydrophobic xylenol were noticed. The presence of Cr3+ ions in the system does not influence the rejection of phenols.

The MEUF has allowed phenols to be concentrated from an aqueous stream. Rejection coefficients of solutes increase with the increase of the surfactant concentration. This study demonstrated the potential of the MEUF for simultaneous removal of organic pollutants such as phenols and inorganic pollutans such as chromium(III) ions. It has been suggested that at the surface of micelles Cr3+ are located due to electrostatic interactions and phenols are solubilized in the hydrophobic interior. Rejection coefficients of surfactants increase abruptly and approach almost 100% for the highest CTAB and SDS concentrations. CTAB and SDS were convenient surfactants for ultrafiltration, as high rejection of solutes was observed. The MEUF process enables removal of contaminants with high efficiencies. There were no significant interrelations observed between phenols and Cr3+ ions with regard to their separation effects.