Novel hybrid adsorbent for cationic dye decoloration: Zero-valent nickel nanoparticles supported on activated carbon incorporated in electrospun polyacrylonitrile nanofibers

In this study, zero-valent nickel (ZVNi) supported on high porous activated carbon (HPAC) was successfully prepared and impregnated into polyacrylonitrile nanofibers (PAN NFs) by electrospinning to design nanofiber composite called ZVNi@HPAC/PAN NFs. The produced ZVNi@HPAC and PAN NFs its composite were characterized using a variety of characterization techniques, including FESEM, TEM, XRD, EDX, FTIR and TGA. The adsorption performance of the PAN NFs and ZVNi@HPAC/PAN NFs was evaluated under varying conditions of initial concentration of crystal violet dye (CV) (25–1000 mg/L), pH (3–10), temperature (25–40 °C), ionic strength (0.05–0.3 M) and time (5 min–24 h). The synergistic effect on adsorption performance resulting from the combination of the ZVNi@HPAC and PAN NFs was studied by batch adsorption test. Isothermal studies confirmed that the Langmuir model is the most accurate for simulating the results of crystal violet dye adsorption. The ZVNi@HPAC composite exhibited a high adsorption capacity (q_max) of 723.75 mg/g compared to 69.75 mg/g for pure PAN NFs at pH 10 and 40 °C. ZVNi@HPAC showed superior CV dye removal efficiency of 96 % even at high concentrations (300 mg/L), within a short time of 60 min, compared to 27 % efficiency for PAN NFs. The ZVNi@HPAC/PAN NFs exhibit high reusability by keeping adsorption performance at more than 98.79 % after ten reuse cycles.