Selective separation and simultaneous recoveries of amino acids by temperature-sensitive magnetic ionic liquid aqueous biphasic system

Abstract

Two temperature-sensitive magnetic ionic liquids (MILs) based on polypropylene glycol 600 were used to construct novel temperature-sensitive magnetic ionic liquid aqueous biphasic systems (MILABSs) with different inorganic salts. Phase behaviors were studied in detail to give useful guidance for practical separation applications. These developed temperature-sensitive MILABSs were further employed for the selective separation of arginine and tyrosine mixtures as well as their simultaneous recoveries. Several factors affecting extraction efficiencies of both amino acids were optimized to achieve satisfactory selectivity. Magnet was applied to enhance phase separation efficiency. After extraction, for the MIL-rich phase, both pure arginine and MIL were perfectly recovered simply by heating. For the salt-rich phase, pure tyrosine was easily obtained simply by pH adjustion and cooling. This is the first time to realize simultaneous recoveries of targeted compounds from both MIL-rich phase and salt-rich phase for a temperature-sensitive MILABS. The whole separation and recovery processes were simple and free of any organic solvents. Moreover, temperature-sensitive MIL could be reused for at least 6 times with steadily satisfactory extraction performances. These specific temperature-sensitive MILABSs applied for selective separation and simultaneous recoveries of amino acids is revealing great potential for the simultaneous recoveries of different targeted compounds in an industrial separation-recovery process.