Reclaiming Waste: Comparative Insights into Plastic-Derived and Spent RO Filter Activated Carbons"

Abstract

The alarming rise in plastic waste and the growing volume of spent activated carbon from domestic and industrial reverse osmosis (RO) filters have raised serious environmental concerns. This study explores a sustainable valorization pathway by comparing activated carbon derived from pyrolyzed plastic waste with spent activated carbon recovered from used RO filters. Plastic waste, an abundant and carbon-rich resource, was thermally decomposed via pyrolysis to yield char, which was subsequently chemically activated using 1N KOH at various impregnation ratios. A series of characterizations, including CHNS elemental analysis, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and iodine number assessments, was conducted to evaluate the physicochemical properties and adsorption-relevant features of both materials. The aim was to assess the structural and elemental differences arising from their distinct origins and preparation routes. The study reveals key insights into the surface morphology, functional groups, and porosity development in both plastic-derived and RO-spent activated carbons. By juxtaposing the two materials, this research provides a comprehensive understanding of their comparative effectiveness and potential as alternative carbonaceous adsorbents. The findings contribute to advancing circular economy practices through waste-to-resource strategies, particularly in the development of low-cost, sustainable activated carbon materials.