阳离子表面活性剂Aliquat 336对水中双酚A的浊点萃取及作用机制

Cloud Point Extraction of Bisphenol A from Water Utilizing Cationic Surfactant Aliquat 336

研究了阳离子表面活性剂Aliquat 336(三辛基甲基氯化铵)浊点萃取水中双酚A(BPA)后以高效液相色谱测定的方法。探讨了Aliquat 336与Na2SO4/NaCl用量、pH值、萃取时间等因素对萃取效果的影响,经条件实验选定各因素水平如下:0.8 g/L Aliquat 336,4.0 g/L Na2SO4,超声萃取15 min,pH和对萃取影响不大,故不予调节。结果表明:在此选定条件下,本方法富集效率高(BPA在胶束相-水相分配系数达104),萃取效率稳定(相对标准偏差均小于10%),其对BPA在不同水质、不同加标浓度下的回收率均大于90%,去离子水中检出限为0.34μg/L。本方法操作简单、方便、成本低,易于推广。同时以胶束粒径与Zeta电位分析等确证盐含量对阳离子表面活性剂胶束形成的决定性作用,并结合影响因子分析,推测Aliquat 336浊点萃取过程中BPA可能存在静电作用、阳离子-π键等疏水分配以外的作用机制。

Cloud point extraction （CPE） utilizing a cationic surfactant, tricaprylmethylammonium chloride （Aliquat 336）, was carried out to separate and concentrate bisphenol A（BPA） from aqueous media. Cloud point phase separation of Aliquat 336 at room temperature （about 25℃） was induced by the addition of Na2SO4. The parameters affecting extraction efficiency, such as concentrations of Aliquat-336 and NazSO4, pH, and equilibration time were evaluated. The results showed that the extraction efficiency was practically constant in the studied range of Aliquat 336, co-solvent（methanol） , pH and dissolved organie matters. At the operational CPE conditions, distribution constant, KD, of the distribution of BPA between the surfactant-rich and aqueous phases of the CPE system was estimated to be 104. Coupled to liquid chromatography with UV detection, the CPE method offered a detection limit of 0.34μg/L in distilled water and recovery of BPA ranged from 90% to 108.6% with a sample volume of 50 mL in three matrices studied. The high extraction efficiency might be due to combination of ion-pair, hydrophobie effects and cation-or interaction, based on the micelles＇ size distribution and zeta potential analysis.