合成了疏水性胍类离子液体,考察室温下离子液体对水溶液中金属离子(Fe^3+、Cu^2+、Co^2+、Ni^2+、Zn^2+)的萃取能力。实验结果表明该离子液体对Fe^3+萃取具有高选择性,萃取率为90%;对其他金属离子萃取率仅为40%左右。为了进一步研究离子液体对Fe3+的萃取性能,分别从两相体积比、萃取时间、金属离子起始浓度及溶液pH等因素研究了其对Fe^3+的捕集效果。结果表明:室温下,0.2mL离子液体与5mL的FeCl3溶液超声混合5min后,溶液中Fe^3+萃取率为90%;且溶液中金属离子的起始浓度对萃取效果影响较小,但溶液pH对其影响较大。通过实验与理论计算发现,离子液体对Fe^3+的萃取过程存在阳离子交换与离子对的共同作用机制,但离子对作用占主导地位。
The hydrophobic guanidine ionic liquid was synthesized to study the extraction of heavy metal ions(Fe^3+ ,Cu^2+ ,Co^2+ ,Ni^2+ ,Zn^2+) from aqueous solution at room temperature. The results showed the extraction efficiency of Fe^3+ was up to 90% ,while that of other metal ions was about 40%. In order to further study the extraction effect of Fe^3+ , 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 FeCl2 solution were mixed by supersonic vibration at room temperature, the extraction efficiency of Fe^3+ was 90 %. The results also suggested that initial concentration of metal ions in solution had little effect on the extraction efficieney,however,pH had great effect on it. The experiment results and theoretical calculations proved that the mechanisms of the extraction for Fe^3+ were the ion-pair and the cation exchange, in which the ion-pair played the main role.