Functionalized diatomite/oyster shell powder doped electrospun polyacrylonitrile submicron fiber as a high-efficiency adsorbent for removing methylene blue from aqueous solution: Thermodynamics, kinetics and isotherms

Abstract A novel diatomite/oyster shell (DS) powder doped polyacrylonitrile composite fiber adsorbent was fabricated via electrospinning technology and anion functionalization (fun-PAN/DS) was carried out with sodium hydroxide and sodium bicarbonate. The influences of different parameters such as solution pH, contact time, temperature and initial concentration on the adsorption of methylene blue (MB) were investigated in batch mode. The adsorption data showed that the removal rate of MB increased from 10.96% to 96.45% with the increase of pH value. The Freundlich isotherm model was found to be best depicting the adsorption of MB on fun-PAN/DS submicron fiber with a maximum capacity of 243.44 mg/g. The pseudo second-order dynamics model (R2 > 0.99) was more suitable for experimental data than other kinetic models. In the summary, fun-PAN/DS fiber with good physicochemical stability is an excellent material to be a high-efficiency adsorbent for removing methylene blue from aqueous solution.