Assessment of Bacteria Filtration from Water Using Polycaprolactone Membrane

Water is essential for life; however, a significant portion of the global supply remains contaminated, which leaves approximately 1.7 billion people without access to safe drinking water. Developing simple, rapid, and effective water purification technologies is, therefore, of critical importance. In this study, biocompatible polycaprolactone (PCL) membranes were fabricated using the air-jet spinning technique, which represents a faster and simpler method for producing thicker and uniformly structured membranes. The bacterial filtration performance of these membranes was evaluated as a function of spraying duration at a fixed deposition rate of 1.20 g/h. Filtration tests demonstrated that the efficiency against Escherichia coli (E. coli) increased from 99.68% after 5 min of spraying to 99.99% after 15 min, whereas the efficiency for Staphylococcus aureus (S. aureus) reached 99.84% and 99.99%, respectively. Additionally, the PCL membranes maintained high bacterial filtration efficiency during tests conducted at various continuous flow rates. Fluorescence imaging and bacterial coverage analysis confirmed that the majority of bacteria were captured on the membrane surface. The surface pore size decreased from 1.16 μm to 0.58 μm with longer spraying durations, thereby primarily contributing to enhanced bacterial filtration, while the membrane thickness reflected the degree of nanofiber accumulation associated with surface pore refinement. The simplicity and speed of these membranes distinguish them from previously reported alternatives, providing particular advantages in low-resource settings and contributing to the expansion of access to safe drinking water.