REMOVAL OF AROMATIC-COMPOUNDS IN THE AQUEOUS-SOLUTION VIA MICELLAR-ENHANCED ULTRAFILTRATION - PART 1 - BEHAVIOR OF NONIONIC SURFACTANTS

The effects of nonionic surfactants having different hydrophilicity an d membranes having different hydrophobicity and molecular weight cut-o ff on the performance of micellar-enhanced ultrafiltration (MEUF) proc ess were examined. A homologous series of polyethyleneglycol (PEG) alk ylether having different numbers of methylene groups and ethylene oxid e groups was used for nonionic surfactants. Polysulfone membranes and cellulose acetate membranes having different molecular cut-off were us ed for hydrophobic membranes and hydrophilic membranes, respectively. The concentration of surfactant added to pure water was fixed at the v alue of 100 times of critical micelle concentration (CMC). The flux th rough polysulfone membranes decreased remarkably due to adsorption mai nly caused by hydrophobic interactions between surfactant and membrane material. The decline of solution flux for cellulose acetate membrane s was not as serious as that for polysulfone membranes because of hydr ophilic properties of cellulose acetate membranes. The surfactant reje ctions for the cellulose acetate membranes increased with decreasing m embrane pore size and with increasing the hydrophobicity of surfactant . On the other hand the surfactant rejections for polysulfone membrane s showed totally different rejection trends with those for cellulose a cetate membranes. The surfactant rejections for the polysulfone membra nes depend on the strength of hydrophobic interactions between surfact ant and membrane material and molecular weight of surfactants. (C) 199 8 Elsevier Science B.V. All rights reserved.