Fabrication of hydrophilic hierarchical PAN/SiO2 nanofibers by electrospray assisted electrospinning for efficient removal of cationic dyes

In this study, a combined electrospinning/electrospray technique was applied to fabricate hydrophilic hierarchical electrospun polyacrylonitrile (PAN) decorated with silica nanoparticles (NPs). The membrane was employed as an efficient adsorbent for eliminating cationic dyes (CDs) of Malachite Green (MG) and Methylene Blue (MB) from aqueous solutions. Investigations were carried out on the structural characterization and performance of the prepared membranes, followed by the equilibrium, kinetics, and thermodynamic studies. The results of the batch adsorption experiments demonstrated the endothermic and pH-dependent processes. The composite and decorated nanofiber (PAN-SiO2 and PAN/SiO2 (ES)) adsorption behavior was described according to the pseudo-first-order and pseudo-second-order kinetic models, respectively. Langmuir and Langmuir–Freundlich isotherm models were applied on the experimental adsorption data to evaluate the maximum dye adsorption capacity onto PAN-SiO2 and PAN/SiO2 (ES). The results indicated that the efficient removal of MG and MB (98.3 and 83.9% for 25 mg/L solutions, respectively) has occurred within 7 min. The membrane could be recycled after acid treatment due to its excellent reusability.