Enhanced CO2 separation membrane prepared from waste by-product of silk fibroin

Abstract

This study involves membrane technology for the CO2 separation using sericin (SC) as a biopolymer and sodium carbonate (Na2CO3) as a mobile carrier. The silk cocoons contain two proteins- 65–85% silk fibroin (SF) and 15–30% of SC. During the silk degumming process, SF is extracted by dissolving in sodium carbonate (Na2CO3), to remove the SC. Although SF has various applications in vivid fields, SC remains as a discarded waste product, which contains primarily serine and glycine amino acids in its polypeptide chain that can be used to enhance the CO2 transport. In this study, we investigated the CO2 separation properties by blending SC in the chitosan (CS) matrix in the presence and absence of Na2CO3. Detailed material characterizations were performed by X-ray Photoelectron Spectroscopy (XPS) and advance microscopic techniques to reveal the layer formations in the membrane active layer. The CS-SC matrix with the inclusion of Na2CO3 displayed remarkable higher CO2/N2 selectivity of ∼9% and ∼40% as compared to that of CS-SC and SC − Na2CO3, respectively at 90 °C. We envision that this work will invigorate a cost and time effective route of membrane preparation for CO2 separation that will have several constructive impacts on the environment.