Thin-film-composite hollow fiber membranes containing amino acid salts as mobile carriers for CO2 separation

Abstract

In this work, defect-free thin-film-composite (TFC) hollow fiber membranes containing various amino acid salts as CO2 facilitated transport carriers were fabricated via dip-coating. Four different amino acid salts, i.e., potassium prolinate (ProK), potassium argininate (ArgK), potassium glycinate (GlyK) and potassium cysteinate (CysK), were selected and embedded within polyvinyl alcohol (PVA) matrix. TGA, FTIR, SEM and humid mixed gas permeation test were used for the evaluation. Experiments show that adding amino acid salts into the PVA matrix significantly increases the CO2 permeance with little influence on the CO2/N2 selectivity. ProK was found the most effective within the four investigated mobile carriers; The addition of 40% ProK into the PVA matrix nearly doubled the CO2 permeance (from 399 to 791 GPU). The PVA/amino acid salt membranes also exhibited good long-term stability, in which both CO2 permeance and CO2/N2 selectivity remained nearly unchanged in a 20-h test and after a two-week shutdown period.