Electrospun chitosan/polymethyl methacrylate nanofiber membranes integrated with polyethyleneimine for enhanced removal of chromium(VI) ions

Abstract

This study demonstrates the preparation of a unique chitosan (CS)/polymethyl methacrylate (PMMA)/polyethyleneimine (PEI) nanofiber (NF) membrane using PMMA as the composite skeleton through an electrospinning method. The chemical and mechanical properties, chromium (Cr) adsorption capabilities, and mass transfer mechanisms of the NF membrane were thoroughly investigated. The findings indicate that the CS/PMMA/PEI NF membranes, with an average diameter of approximately 856.2 nm, exhibits favorable hydrophilicity, effective Cr(VI) adsorption (first adsorption capacity of 226.5 mg g−1), and robust mechanical properties (tensile strength of 1.58 ± 0.092 Mpa), which is superior to most reported adsorbents. Moreover, the composite NF membranes exhibit a second adsorption capacity of 194.4 mg g−1 and a tensile strength of 0.739 ± 0.072 Mpa after the second adsorption, indicating a remarkable level of reusability and cycle stability. Additionally, x‐ray photoelectron spectroscopy, and structural tests reveal the presence of abundant amino (NH2) and hydroxyl (OH) groups in the CS/PMMA/PEI NF membranes, suggesting potential sites for complexation reactions and the reductions of Cr(VI) ions, thereby facilitating effective adsorption and removal of heavy metals. This study introduces a novel and straightforward approach for synthesizing highly effective adsorbents, with have potential implications for the removal of heavy metal ions from wastewater.