Tuning the Biodegradability of Chitosan Membranes: Characterization and Conceptual Design

Sustainable development entails the revival of biopolymer-based membranes for water treatment with the expectation of addressing concerns relevant to the depletion of fossil-based resources and their negative impacts on the environment. However, it is challenging to tune the biodegradability of biopolymer-based membranes such that the filtration performance would be maintained during the service life while reducing the environmental footprint. This study established a conceptual framework of achieving tunable biodegradability by incorporating chitosan membranes with silver nanoparticles. In particular, the membranes were fabricated on the basis of dissolving chitosan in an aqueous urea/alkali solution, which enabled a green approach for forming various porous substructures via phase inversion. The effects of biodegradation on chitosan membranes were investigated in the context of correlating the filtration performance with the geometrical variations in the polymer network. A series of characterization experiments were implemented to corroborate that the degree of protecting the porous substructures against enzymatic digestion should be a function of the silver loading, whereas the service life would be dependent on the silver-leaching rate. Moreover, it was revealed that optimizing the coagulation conditions could be an effective way to control the silver release during the filtration process.