Effect Of Various Surfactant Micelle On Separation Efficiency Of Phenol In Micellar-Enhanced Ultrafiltration

Micellar-enhanced ultrafiltration is a technique combining surfactant with ultrafiltration, which has a good prospect in removing the dissolved low molecular weight organics especially phenol from wastewater. The aim of this work is to study separation efficiency of phenol from various surfactant micelles. Anionic sodium dodecylulfate (SDS), nonionic triton X-100(TX-100) and cationic cetyl trimethyl ammonium bromide (CTAB), as three representative types of surfactants, were adopted in MEUF experiments. Then, three cationic surfactants (CPC, CTAB, OTAB) with group difference, i.e., the same hydrophobic tail length but different hydrophilic head group and vice versa, were used to remove phenol by MEUF. In present work, several parameters including distribution coefficient (D), concentration of phenol dissolved in the micelles (Om) and concentration of surfactant in micelle phase (Sm) were determined to understand the distributions of organic and surfactant between water and micelle phases, and the retentate and permeate.The research results showed that:(1) When anionic、nonionic and cationic surfactants were used to remove phenol, at feed surfactant concentration of10mM, The rejection and distribution coefficient of phenol with CTAB were highest, and the separation efficiency of phenol with three surfactants could be ranked as follows: CTAB> SDS>TX-100.(2) The distribution coefficient of phenol examined with three cationic surfactants raised continuously with increasing feed surfactant concentration from1to30mM, while Om almost raised linearly. D and Om with OTAB in comparison to that with CTAB and CPC increased, and separation efficiency of phenol with OTAB was higher than CTAB and CPC. The rejections of phenol in the presence of three surfactants were pretty close to each other with the range of50%-85%due to the same rejection mechanism, i.e electrostatic interaction. The rejections of three surfactants increased rapidly and achieved around99%beyond5mM. Sm examined with OTAB and CPC was higher than that with CTAB.(3) The permeate flux could be ranked as follows:CPC>CTAB> OTAB. Because of increasing in hydrophobicity and decreasing in CMC, the increase in the number of micelles deposited over the membrane surface or on the pore walls resulted in the membrane fouling and pore plugging, leading to aggravate the degree of membrane pollution, and thereby a corresponding decrease of the flux.