Green synthesis of porous N-Carbon/Silica nanofibers by solution blow spinning and evaluation of their efficiency in dye adsorption

Porous N-carbon/silica nanofibers (PN-CSN) were successfully made by solution blow spinning (SBS), polymer solutions containing polyvinylpyrrolidone (PVP), tetraethyl orthosilicate (TEOS), and ethanol. The fibers samples were carbonized at 550 degrees C in a static air atmosphere. PN-CSN fibers were characterized using scanning electron microscopy, N-2 adsorption/desorption, X-ray diffraction, thermogravimetric analysis and zeta potential. The adsorption capacity was determined using a dye (methylene blue, MB). The PN-CSN fibers had a small average diameter (233 +/- 178 nm), high specific surface area (364 m(2) g(-1)) and pore volume (0.18 cm(3) g(-1)). The pore size distribution ranged from 10 to 170 nm. Chemical analyses of the fibers revealed a residual amount of N (6.2%) and C (20,85%) as is characteristic in ceramic nanofibers made with polyacrylonitrile (PAN). The PN-CSN fibers had an adsorption capacity of approximately 400 mg g(-1). The best fit for the adsorption data was found using a Langmuir model. The adsorption kinetics followed a pseudo-second order model. Thermodynamic analyses revealed the adsorption mechanism was endothermic and spontaneous for PN-CSN adsorbents. (C) 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.orgilicensesiby-ne-nd/4.0/).