Production and characterization of biodegradable AC/PVA nanofibers using activated carbon obtained from cranberry (cornus mas. l.) fruit seeds and investigation of its potential to remove heavy metal pollutants from water

Worldwide, large quantities of by-products and wastes are generated during food and agricultural production processes. While these wastes are effectively valorized into economic products in developed countries, such practices have not yet reached an industrial scale in Türkiye. In this study, activated carbon (KAC) was produced from cornelian cherry (Cornus mas L.) seeds, an agricultural by-product, using ZnCl₂ chemical activation at a 1:1 impregnation ratio. The obtained activated carbon was composited with polyvinyl alcohol (PVA), an environmentally friendly and biodegradable polymer, and AC/PVA nanofibers were fabricated via the electrospinning technique. KAC, pristine PVA nanofibers, and AC/PVA nanofiber adsorbents were characterized using BET surface area analysis, SEM–EDS, FT-IR, XRD, and DSC techniques. The BET surface area of KAC was determined as 1025.7 m²/g, indicating a highly porous structure consistent with biomass-derived activated carbons reported in the literature. Adsorption performance varied depending on both the type of metal ion and the adsorbent structure. For KAC, the highest maximum adsorption capacities (Qmax) were obtained for Pb(II) (110.557 mg/g), Cu(II) (84.231 mg/g), and Cr(VI) (87.234 mg/g). In contrast, the highest Qmax value for Cd(II) was achieved using AC/PVA nanofibers (48.053 mg/g). Kinetic studies revealed that adsorption data followed the pseudo-second-order kinetic model, while isotherm analysis showed better agreement with the nonlinear Langmuir model. Overall, the results demonstrate that both activated carbon and AC/PVA nanofibers derived from Cornus mas L. seeds are effective and sustainable adsorbents for heavy metal removal in wastewater treatment.