Green synthesis of porous N-Carbon/Silica nanofibers by solution blow spinning and evaluation of their efficiency in dye adsorption
Rosiane Maria da Costa Farias, Mariaugusta Ferreira Mota, Lucas Leite Severo, Eliton S. Medeiros, Artur P. Klamczynski, Roberto J. Avena‐Bustillos, Lisiane Navarro de Lima Santana, Gelmires de Araújo Neves, Gregory M. Glenn, Romualdo Rodrigues Menezes
Abstract
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 °C in a static air atmosphere. PN-CSN fibers were characterized using scanning electron microscopy, N2 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 m2 g−1) and pore volume (0.18 cm3 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.