Research On Phase Composition Of Aqueous Two Phase System In Mixtures Of Anionic And Cationic Surfactants

Environmentally friendly Aqueous Two-phase System (ATPS) consist of cationic and anionic surfactant was used in extraction of biological material and heavy metal ion. The ATPS consisted of cationic surfactant (CTAB:CetylTrimethyl Ammonium Bromide) and anionic surfactant (SDS:sodium dodecyl sulfate) was chosen to extract biological material (BSA, Trypsin) and heavy metal ion (Hg2+, Cd2+). Effects of various factors on the distribution role of extracted materials and phase behavior were researched.It was found that extraction in the two ATPS region (ATPSa:anionic surfactants are in excess, ATPSc:cationic surfactants are in excess) exist obvious differences when BSA and Trypsin were extracted. Electrostatic interaction was the leading role during extraction in ATPSa. They can be extracted only when protein with positive charge. The hydrophobic interaction was the leading role in ATPSc. No matter the protein carries positive or negative charge, the extraction results were very good. And the distribution ratio is higher than ATPSa. When extraction of heavy metal ion was conducted, the effects of various factors on stability of complex were explored first. It was found that the stability of complex was very well. The forms of the complex did not change during extraction progress. Secondly, the effects of various factors on the distribution ratio of complex and volume ratio were discussed. This progress helped us to explore the relationship between distribution and the microstructure of ATPS. It was found that changes of experimental conditions effected extraction results heavily. The distribution ratio of complex increases with the increase of salt concentration, decreases with the increase of surfactant concentration. The extraction results were the best when solution was neutral. The higher the temperature is, the better the result is, it can reach stability in short time. These effects of factors on extraction results were achieved through alter the microstructure of the organized assembles in ATPS. The changes of distribution role were the response to effects of various factors on phase behavior.It can be concluded through this research that the application of ATPS which is formed by cationic and anionic surfactant in extraction of heavy metal ion field was very good and its potential use is very huge.