In this work,experiments to examine the recycling of ionic liquids(ILs)from aqueous solution by nanofiltration(NF)were conducted.The influences of pH,ionic strength,and macromolecular organic matter on filtration perf...In this work,experiments to examine the recycling of ionic liquids(ILs)from aqueous solution by nanofiltration(NF)were conducted.The influences of pH,ionic strength,and macromolecular organic matter on filtration performance metrics including the volume flux(J_(v))and observed rejection(R_(obs))were systematically studied.Aqueous solutions of three widely studied ILs,specifically 1-butyl-3-methylimidazolium chloride([C_(4)mim]Cl),1-decyl-3-methylimidazolium chloride([C_(10)mim]Cl),and 1-buty 1-3-methylimidazolium tetrafluoroborate([C_(4)mim]BF_(4))were selected for this study.The mechanisms of interaction between the ILs and the NF membrane under different pH and ionic-strength conditions were revealed by quantum chemical calculations and molecular simulations.The results showed that with increasing pH,the J_(v) and R_(obs)values of the[C_(4)mim]Cl and[C_(10)mim]Cl aqueous solutions increased,while for the[C_(4)mim]BF_(4)aqueous solution,the J_(v) value increased and the R_(obs)value decreased.Furthermore,with increasing ionic strength,the J_(v) values of the[C_(4)mim]Cl and[C_(4)mim]BF_(4)aqueous solutions decreased,and their R_(obs)values increased;conversely,for the[C_(10)mim]Cl aqueous solution,the R_(obs)value decreased,and the J_(v) vale first increased and then decreased.In addition,it was found that the presence of macromolecular organic matter tends to cause membrane fouling and has a great influence on the separation of aqueous solutions of ILs by NF.In general,membrane fouling leads to an increase in the R_(obs)value but a decrease in the J_(v) value.展开更多
文摘In this work,experiments to examine the recycling of ionic liquids(ILs)from aqueous solution by nanofiltration(NF)were conducted.The influences of pH,ionic strength,and macromolecular organic matter on filtration performance metrics including the volume flux(J_(v))and observed rejection(R_(obs))were systematically studied.Aqueous solutions of three widely studied ILs,specifically 1-butyl-3-methylimidazolium chloride([C_(4)mim]Cl),1-decyl-3-methylimidazolium chloride([C_(10)mim]Cl),and 1-buty 1-3-methylimidazolium tetrafluoroborate([C_(4)mim]BF_(4))were selected for this study.The mechanisms of interaction between the ILs and the NF membrane under different pH and ionic-strength conditions were revealed by quantum chemical calculations and molecular simulations.The results showed that with increasing pH,the J_(v) and R_(obs)values of the[C_(4)mim]Cl and[C_(10)mim]Cl aqueous solutions increased,while for the[C_(4)mim]BF_(4)aqueous solution,the J_(v) value increased and the R_(obs)value decreased.Furthermore,with increasing ionic strength,the J_(v) values of the[C_(4)mim]Cl and[C_(4)mim]BF_(4)aqueous solutions decreased,and their R_(obs)values increased;conversely,for the[C_(10)mim]Cl aqueous solution,the R_(obs)value decreased,and the J_(v) vale first increased and then decreased.In addition,it was found that the presence of macromolecular organic matter tends to cause membrane fouling and has a great influence on the separation of aqueous solutions of ILs by NF.In general,membrane fouling leads to an increase in the R_(obs)value but a decrease in the J_(v) value.
