| In a large number of wastewater, such as textile, printing and dyeing,papermaking, etc., there are toxic and difficult biodegradation organic dyes which arethreat to ecological environment. As the criterion of environmental protectionbecomes more and more stringent, the wastewater can not be treated efficiently ontechnology and economy aspects with the taditional techniques. Micellar-EnhancedUltrafiltration (MEUF) is a new technology, based on the surfactant and ultrafiltration.It utilizes the surfactant micelization effect, solubilization of micelles and then theultrafiltraion to retain the organic pollutants. This technology has a series ofadvantages, such as high efficiency, low operative pressure, high permeate flux, lowenergy consumption, at room temperature, simple process and easy to achieveindustrialization.With the increase of feed SDS concentration (0~72.0mM)，the retentate andpermeate SDS and MB concentrations increased. It was attributed to the more SDSmicelles aggregated, leading to more MB molecules solubilized. And then themicelles along with the MB were retained by the membrane. Meanwhile, the permeateflux (J) decreased and additional resistance (Rf) increased. It was efficient andeconomical to add8.0mM SDS into the feed solution that contained2~6mg/L MB.For the additional resistance (Rf), the dosage of SDS and secondary pollution werelow, while the permeate flux (J) was higher. As the pressure increased from0.01MPato0.09MPa, the removal efficiency of MB and SDS, the retentate MB and SDSconcentrations decreased slightly. Temperature influenced the property of SDSmicelle, such as CMC and solubilizing space. As the temperature increased from20°C to35°C, the retentate MB concentration ascended, since the solubilizing space inmicelles became a little bigger. With temperature from35°C to45°C, the retentateMB concentration decreased. It was attributed to the decrease of the SDS micelles inthe retentate. The removal efficiencies of MB and SDS were slightly dependent on thevariation of temperature. The permeate flux increased with increasing temperature.This was attributed to the following two causes: membrane pores might be expandedwith the increase of temperature; the viscosity of the aqueous solution (p) reduced,the solution could pass through the membrane more easily. Correspondingly, theadditional resistance increased with the temperature. For more solutes weretransported to the membrane surface as the permeate flux increased, leading to theincrease of membrane adsorption and concentration polarization. The pH didn’t effect the process in MEUF of MB significantly. NaCl could promote the solubilizationcapability of SDS micelles for MB. When NaCl was added to the solution, the Na+with opposite charge could result in a decrease of the CMC of SDS and an increase ofthe aggregation number of the SDS micelles. The retentate MB and SDSconcentrations increased with the feed NaCl concentration. The removal efficiency ofMB kept99.3%, the removal efficiency of SDS acended from63.48%to96.00%. Sothe NaCl could reduce immensely the secondary pollution, the adsoption of MB on themembrane and crucially did not influence the low permeate MB concentration.This work studied the effect of operating parameters on distribution constant (Kd)and micelle loading (Lm), which reflected the relative change of the components inretentate and permeate. Through the measurement of zeta potential, the effects of SDS,MB and NaCl cocentrations on the performance of SDS micelles formation wereinvestigatied.As shown in the research, MEUF using SDS and polysulfone hollow fibermembrane could solubilize and retain MB in water effectively and quickly. Theaddition of NaCl could immensely reduce the secondary pollution and increase therejections of SDS and MB remarkably. In this paper, key in the influence ofcontrolling parameters on MEUF of MB in water was studied and discussed. Thisstudy had foundation for application and popularization of dye-containing wastewatertreatment using MEUF. |
PDF Full Text Request