Nanofiltration of Nonionic Surfactants: Effect of the Molecular Weight Cutoff and Contact Angle on Flux Behavior

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• 作者：Geert Cornelis ; Katleen Boussu ; Bart Van der Bruggen ; Ilse Devreese ; and Carlo Vandecasteele
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2005
• 出版时间：September 28, 2005
• 年：2005
• 卷：44
• 期：20
• 页码：7652 - 7658
• 全文大小：189K
• 年卷期：v.44,no.20(September 28, 2005)
• ISSN：1520-5045

文摘

Nonionic surfactants are widely used in industry, and large amounts of wastewater containingnonionic surfactants are produced each year. Nanofiltration (NF) is a possible option to purifythese waters, reducing the overall water consumption and enhancing biological purification.However, the flux behavior of NF during purification of wastewaters containing nonionicsurfactants is not well understood. NF tests were performed with both synthetic solutions andreal wastewaters containing nonionic surfactants from carpet rinsing. When a membrane witha relatively high molecular weight cutoff (MWCO) was chosen, flux decreased to a level lowerthan that with most ultrafiltration membranes. When a low MWCO was chosen, flux eitherincreased above pure water flux when a relatively hydrophobic membrane was chosen ordecreased when a relatively hydrophilic membrane was chosen. NF thus seems feasible to reducewater usage in industrial processes involving nonionic surfactants when a proper membrane isselected. It appeared that flux is controlled by three mechanisms: first, the narrowing ofmembrane pores through adsorption of monomers when the MWCO is comparable or largerthan the monomer size, causing flux decline; second, an improved wettability of the membranesurface through adsorption of monomers on hydrophobic groups, causing flux to increase abovepure water flux; third, a decreased wettability through adsorption of monomers on hydrophilicgroups, causing flux decline. The nonionic surfactant concentration, MWCO, and membrane'shydrophilicity determine which mechanism is dominant.