ABSTRACT
Aliquat 336 functionalized chelating adsorbent derived from chitosan for enrichment and separation of Y(Ⅲ) were investigated by static adsorption method. The adsorption of Y(Ⅲ) was greatly influenced by the pH of solution, and reached maximum at 20 ℃ using 90 mg/L Y(Ⅲ) at pH 4. 9, and the adsorption of Y(Ⅲ) followed a pseudo-second-order kinetics model and the Langmuir isotherm model. The reduction of Y(Ⅲ) adsorption with the increasing of temperature meant that the adsorption process was exothermic. XPS analysis demonstrated that both cations and anions of the adsorbent were involved in adsorption process, thereby resulting in an improved adsorption of Y(Ⅲ). The adsorbent was thus efficient for enrichment and separation of rare earths from waste rare earth phosphor.
ABSTRACT
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 Na_2SO_4. The parameters affecting extraction efficiency, such as concentrations of Aliquat-336 and Na_2SO_4, 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 organic matters. At the operational CPE conditions, distribution constant, K_D, of the distribution of BPA between the surfactant-rich and aqueous phases of the CPE system was estimated to be 10~4. Coupled to liquid chromatography with UV detection, the CPE method offered a detection limit of 0.34 μg/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, hydrophobic effects and cation-π interaction, based on the micelles' size distribution and zeta potential analysis.