Ultrafiltration characteristics of oxyethylated methyl dodecanoate aqueous solutions

The effects of the hydrophilicity of oxyethylated methyl dodecanoates and type and concentration of electrolyte on micellar enhanced ultrafiltration of phenol and 4-methylphenol were studied. It was found that oxyethylated methyl dodecanoates with the average degree of oxyethylation not lower than 9 are suitable surfactants for micellar enhanced ultrafiltration of neutral forms of phenol and 4-methylphenol. The rejection near 80% can be obtained. The ultrafiltration fluxes and the resistance of the secondary layer depend on the hydrophilicity of oxyethylated methyl dodecanoates, and type and concentration of electrolytes. These effects are connected with the formation of the gel layer and polarisation effect induced by the presence of the salting-out electrolyte (NaCl) and low cloud point of insufficient hydrophilic surfactant. The salting-in electrolyte (KSCN) exhibits a relatively small negative effect on ultrafiltration flux and resistance.