Structurally stable electrospun nanofibrous cellulose acetate/chitosan biocomposite membranes for the removal of chromium ions from the polluted water

Cellulose acetate (CA) and chitosan (CS) were selected as the raw materials for preparing the biobased porous nanofibers for the removal of chromium ions in aqueous solutions. The structurally stable nanofibrous biocomposite membranes were successfully electrospun fabricated using a double-needle method. Nanoindentation mapping revealed that the micro or nano-scale knots were formed through a synergistic action of the hydrogen bonding, electrostatic forces, and interfacial compatibility of CA and CS. The average elastic modulus and hardness values of CA/CS biocomposite nanofibers were 0.23 GPa and 1.72 GPa, respectively. The nanofibrous membrane exhibited outstanding structural stability in an aqueous solution (with a wide pH range) and good thermal stability. The biocomposite nanofibrous membrane with 50% CS loading (BENF-50) had an optimum adsorption capacity of 51.6 mg/g for chromium ions in the aqueous solution at pH = 3 as well as good reusability of up to eight cycles. The fabricated biocomposite nanofibrous membranes showed excellent structural stability, thermal stability, and adsorption performance, making them promising adsorbent materials for treating water pollution. Graphical Abstract