Synergetic impact of binary/ternary zeolitic composites on cellulose acetate membranes for potential CO2 removal and antibacterial attributes

Abstract

The aim of this research is to synthesize multifunctional mixed matrix cellulose acetate (CA) membranes that can provide better CO₂/N₂ selectivity and will simultaneously fight against bacteria, to immaculate the indoor environment. For that purpose, two different fillers labelled as binary ZnO@Zeolite (1:10, ZZ) and ternary ZnO–CuO@Zeolite (0.8:0.2:10, ZZC) composites have been synthesized via co-precipitation method to entrench into CA matrix with 8 wt% each. The solution mixing technique assisted by thermal evaporation process (TEAP) has been adopted to formulate the desired membranes. Surface morphology, crystalline structure, thermal decomposition, and mechanical properties of novel composites ZZ and ZZC, along with their respective corresponding membranes CA/ZZ-8 and CA/ZZC-8, have been analyzed using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and universal testing machine (UTM). The inclusion of tri-zeolitic composite (ZZC) favors the formation of denser CA membranes, with a smaller crystallite size (10.8 nm), higher thermal stability (%), and a notable increase in mechanical strength (MPa) in contrast to virgin CA as well as bi-zeolitic composite (ZZ) loaded membranes. The selectivity for CO₂/N₂ separation of tri-zeolitic composite loaded membranes (CA/ZZC-8) is almost six folds higher compared to the pristine CA membrane, whereas it is five folds for bi-zeolitic composite impregnated membrane (CA/ZZ-8). To eradicate bacterial fouling, bi/tri-zeolitic composite loaded membranes are tested against E. coli bacteria by broth culture method and the results validate their antibiotic nature. Synthesized novel CA membranes with hybrid composites provide convenient access towards the development of multipurpose membranes.