| Popis: |
A precipitation method is proposed to recover anionic surfactants from a micellar-enhanced ultrafiltration (MEUF) process. Monovalent potassium ion is used to precipitate the dodecylsulfate anion from sodium dodecylsulfate (SDS). The recovery process is quick and clean and requires adding smaller amounts of the electrolyte than if the sodium cation is used to precipitate dodecylsulfate. No substantial loss of organic solutes (phenol and tert-butylphenol) occurs during the precipitation, as was observed when sodium ion was used as the precipitant. It has been shown that potassium dodecylsulfate (KDS) is similar to SDS in its cmc, water solubility, and ability to solubilize organic solutes in micellar solutions. However, KDS has a significantly higher Krafft point than SDS (35 °C). An MEUF experiment using KDS as the model surfactant gave large rejection of tert-butylphenol (96%). Based on these findings, KDS is proposed as a potential surfactant for use in MEUF, with recovery of the surfactant to be accomplished by lowering the system temperature below the Krafft point. |
