In situ green synthesis of iron nanoparticles on PVA nanofiber and its application in adsorptive removal methylene blue

Abstract

This study presents a novel approach for environmentally friendly paint removal, focusing on the efficient removal of methylene blue from aqueous environments using iron nanoparticles embedded in polyvinyl alcohol nanofibers. Iron nanoparticles were synthesized via a green method employing green tea extract under optimized conditions and characterized by FESEM, DLS, TGA, DTG, EDS, FTIR, and XRD. The average size of synthesized iron nanoparticles was 22 nm. Two fabrication techniques were employed to embed the nanoparticles into polyvinyl alcohol nanofibers: electrospinning of a solution containing iron nanoparticles, and in situ synthesis of nanoparticles on the PVA nanofibers. Comparative analyses revealed superior methylene blue adsorption rates when nanoparticles were synthesized in situ on the nanofibers. Characterization techniques, including FESEM, XRD, and FTIR, confirmed the successful formation of nanoparticles on the nanofibers. Response surface method using central composite design (CCD) was performed to find the optimal removal conditions. Optimal removal (85%) occurred under adsorption conditions of pH 8.6, an initial methylene blue concentration of 30 mg/L, a nanofiber dose of 1.6 g/L, and a contact time of 100 min. Kinetic studies demonstrated a pseudo-second-order adsorption model, while Langmuir isotherm analysis indicated a maximum adsorption capacity of 24.509 mg/g. Thermodynamic analysis suggested the spontaneous and exothermic nature of the adsorption process. This composite membrane is an efficient and economical method for removal dye from wastewaters.