Azadirachta indica Mediated Functionalization of MWCNTs by Ferrites of Nickel and Cobalt for the Remediation of As(III) Ions

Removal of arsenic from drinking water is challenging and the most significant global concern. In this study, multi-walled carbon nanotubes (MWCNTs) after surface functionalization with nickel ferrite (MWCNTs/NFO) and cobalt ferrite (MWCNTs/CFO) were used as adsorbents for As(III) ions. The functionalization was carried out by hydrothermal method using Azadirachta indica (neem) extract as a green source. The morphology, thermal stability, structure and magnetic behavior of adsorbents were characterized using FTIR, XRD, TGA, TEM and VSM. For investigation of the sorption behavior of As(III), batch tests were performed under the effect of pH, time, concentration, temperature and dose. Kinetics study suggests that the pseudo 2^nd order model fits well, while the Langmuir model confirms the sorption data. Thermodynamic and desorption studies exhibited that the governing mechanism is chemisorption. The conducted work revealed that MWCNTs/NFO labeled as CN1 served as the best candidate due to high removal efficiency of about 96% for As(III).