Extraction of Heavy Metal Ions from Aqueous Solution with Hydrophobic Guanidine Ionic Liquid

The hydrophobic guanidine ionic liquid was synthesized to study the extraction of heavy metal ions(Fe³⁺,Cu²⁺,Co²⁺,Ni²⁺,Zn²⁺) from aqueous solution at room temperature.The results showed the extraction efficiency of Fe³⁺ was up to 90%,while that of other metal ions was about 40%.In order to further study the extraction effect of Fe³⁺,the influences of volume ratio between aqueous solution and ionic liquids,extracted time,the initial concentration of metal ion,as well as pH were analyzed with the ionic liquid.When 0.2 mL ionic liguid and 5 mL FeCl₃ solution were mixed by supersonic vibration at room temperature,the extraction efficiency of Fe³⁺ was 90%.The results also suggested that initial concentration of metal ions in solution had little effect on the extraction efficiency,however,pH had great effect on it.The experiment results and theoretical calculations proved that the mechanisms of the extraction for Fe³⁺ were the ion-pair and the cation exchange,in which the ion-pair played the main role.