Adsorptive removal of malachite green dye by functionalized electrospun PAN nanofibers membrane

PAN (polyacrylonitrile) nanofibers membrane was synthesized by electrospinning method and its cyanide functional groups were modified into carboxylate anions by sodium hydroxide and sodium bicarbonate respectively. The functionalized PAN nanofibers membrane was used as adsorbent for removal of cationic dye, malachite green (MG) from the aqueous solution. Characterization of functionalized PAN nanofibers was done by atteunated total reflectance (ATR-FTIR), UV-visible spectroscopy, field emission scanning electron microscopy (FE-SEM), and Brunauer-Emmert-Teller (BET) analytical techniques. A series of adsorption experiments were carried out to investigate the effect of pH value, contact time, initial solution concentration and temperature on the adsorption performance. The experimental results showed that 99 % MG dye was removed by functionalized PAN nanofibers within 30 min of contact time. The equilibrium adsorption capacity was found to be 200 mg/g which was almost 5 times higher than that of un-functionalized PAN nanofibers membrane. The adsorption of MG dye onto the carboxylate functionalized nanofibers follows Langmuir adsorption isotherm, and the kinetic study indicates a pseudo second order kinetic model.