Polymers of intrinsic microporosity (PIMs) are composed of highly rigid and contorted structures that lead to inefficient packing. Since their introduction, PIMs have received significant attention from the membrane research community. Particularly, PIM-1 has been studied extensively since it was found to surpass Robeson's upper bound for several gas pairs. In this work, PIM-1 has been chemically modified (Figure 1) and the adsorption and separation properties of PIM-1 and modified PIM-1s have been examined. Hydrolysis of PIM-1 was performed in the presence of NaOH solutions (H2O/ethanol). The reaction resulted in a mixture of hydrolysis products. The reduction of nitrile to primary amine was achieved using borane dimethyl sulphide complex, resulting in amine PIM-1. The reaction of PIM-1 with ethanolamine and diethanolamine produced hydroxyalkylaminoalkylamide PIMs. Figure 1: Polymers of intrinsic microporosity, PIM-1, (a) hydrolysed PIM-1 products, (b) amine PIM-1, (c) ethanolamine and diethanolamine modified PIM1s. Volumetric gas sorption studies of modified PIMs showed that the sorption capacities of polymer altered, depending on the modification. Also, modified PIMs showed enhanced CO2/N2 ideal selectivities at 1 bar compared to parent PIM-1. Although chemical modifications reduced the permeability of the membranes, enhanced gas selectivities were also achieved in permeation studies. Enhanced H2/CO2 selectivity placed amine PIM-1 above the 2008 Robeson upper bound. The relationship between the degree of conversion and permeability of amine PIM-1 was studied in detail. The effect of temperature and pressure on the permeability of amine PIM was studied, using several different temperatures and pressures. Ethanolamine modified PIM showed size selective behaviour by enhanced H2/N2 and H2/CH4 selectivities, and it crossed the 2008 Robeson upper bounds. Dye adsorption studies revealed that chemical modification manipulated the interaction ability of PIM-1. PIM-1 showed high affinity for neutral dye. While hydrolysed PIMs showed high affinity for cationic species, amine and ethanolamine modified PIMs displayed high affinity for anionic dyes.
Tailoring the selectivity of PIM-1 via chemical modification
Johannes C Jansen;Alessio Fuoco;
2016
Abstract
Polymers of intrinsic microporosity (PIMs) are composed of highly rigid and contorted structures that lead to inefficient packing. Since their introduction, PIMs have received significant attention from the membrane research community. Particularly, PIM-1 has been studied extensively since it was found to surpass Robeson's upper bound for several gas pairs. In this work, PIM-1 has been chemically modified (Figure 1) and the adsorption and separation properties of PIM-1 and modified PIM-1s have been examined. Hydrolysis of PIM-1 was performed in the presence of NaOH solutions (H2O/ethanol). The reaction resulted in a mixture of hydrolysis products. The reduction of nitrile to primary amine was achieved using borane dimethyl sulphide complex, resulting in amine PIM-1. The reaction of PIM-1 with ethanolamine and diethanolamine produced hydroxyalkylaminoalkylamide PIMs. Figure 1: Polymers of intrinsic microporosity, PIM-1, (a) hydrolysed PIM-1 products, (b) amine PIM-1, (c) ethanolamine and diethanolamine modified PIM1s. Volumetric gas sorption studies of modified PIMs showed that the sorption capacities of polymer altered, depending on the modification. Also, modified PIMs showed enhanced CO2/N2 ideal selectivities at 1 bar compared to parent PIM-1. Although chemical modifications reduced the permeability of the membranes, enhanced gas selectivities were also achieved in permeation studies. Enhanced H2/CO2 selectivity placed amine PIM-1 above the 2008 Robeson upper bound. The relationship between the degree of conversion and permeability of amine PIM-1 was studied in detail. The effect of temperature and pressure on the permeability of amine PIM was studied, using several different temperatures and pressures. Ethanolamine modified PIM showed size selective behaviour by enhanced H2/N2 and H2/CH4 selectivities, and it crossed the 2008 Robeson upper bounds. Dye adsorption studies revealed that chemical modification manipulated the interaction ability of PIM-1. PIM-1 showed high affinity for neutral dye. While hydrolysed PIMs showed high affinity for cationic species, amine and ethanolamine modified PIMs displayed high affinity for anionic dyes.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
