Electrospun nanofiber from various source of expanded polystyrene (EPS) waste and their characterization as potential air filter media

This paper reported on the fabrication of nanofibrous membranes from various sources of expanded polystyrene (EPS) waste using electrospinning technique and their application as air filter media. The filter membranes were made from four EPS waste sources, i.e. food packaging, EPS craft, instant noodle cup, and electronic packaging. The properties of the membranes fabricated from those sources were compared to obtain the best EPS waste source for air filter application. To make the precursor solutions, those samples were dissolved in d-limonene:DMF with the concentration of 15, 20, and 25 wt%. The solid EPS density, solution viscosity, and surface tension were measured. The fiber diameter and morphology of nanofibers were characterized by scanning electron microscopy (SEM) for each EPS variation. The fabricated membrane properties (crystallinity, wettability, and mechanical strength) and filtration properties (pressure drop, PM2.5 filtration efficiency, and quality factor) were fully characterized and analyzed. Homogeneous fiber diameter with various morphologies (beaded, wrinkled, and smooth fiber) were obtained from all samples with hydrophobic to super-hydrophobic surface (water contact angle ranging from 106 to 153°). Also, the EPS solid density affected the solution viscosity with the expression of η = 0.132 ρ0.29, which then affected the fabricated membrane packing density, porosity, and mechanical properties. Overall, the experimental results showed that all EPS nanofiber filters had great potential as an air filter media. The EPS filter made from food packaging waste with the solution concentration of 15 wt% exhibited the highest efficiency and quality factor of 99.99% and 0.15 Pa−1, respectively.