Green synthesis of a high capacity magnetic polymer nanocomposite sorbent based on the natural products for removal of Reactive Black 5.

Cumin seeds extract containing plant polyphenols was used as a reducing agent forthe preparation of iron-based magnetic nanoparticles. Then, functionalised magnetic nanoparticles (FMNPs) and chitosan were used to synthesise a novel magnetic polymeric nanocomposite (MPNC) with high efficiency and fast sorption kinetics for Reactive Black 5 removal. FMNPs and MPNC were characterised by Fourier transform infrared, vibrating sample magnetometer, field emission scanning electron microscopy, X-ray diffraction, and Zeta potential. The functionalised magnetic nanoparticles had a spherical shape with the size in the range of 22–38 nm that was covered with chitosan. The zeta potential of MPNC was +59.7 mV. Thepresence of Fe3O4 nanoparticles in MPNC sorbent and its crystalline structure was confirmed by FTIR and XRD, respectively. Results showed that the synthesised sorbent has an excellent sorption behaviour for Reactive Black 5 at room temperature and pH range of 5.5–6.5. The time required to reach equilibrium for various concentrations of Reactive Black 5 was ~ 100 seconds, and a 120 mg L−1of dye solution was 92% decolourised within this time. Experimental data were best fitted to the semi-first-order kinetics and Halsey thermodynamic models. The sorbent maximum capacity was 989.9 mg g−1. [ABSTRACT FROM AUTHOR]