Facile and Affordable Fabrication of Chitosan-Stabilized Zero-Valent Iron/Nickel Bimetallic Nanoparticles for Highly Efficient Removal of Azo Direct Blue 86 Dye from Aqueous Media

In this study, chitosan (CS) stabilized bimetallic zero-valent iron (ZVI)-nickel (CS-nZVI-Ni) nanoparticles were synthesized for the removal of Direct Blue 86 (DB 86) from aqueous media. Analysis of the CS-nZVI-Ni characteristics was investigated by scanning electron microscope, energy dispersive X-ray analysis, Fourier transform infrared spectroscopy, X-ray diffraction, and Brunauer-Emmett-Teller methods. The effective experimental parameters, including pH of the solution, contact time, adsorbent dosage, and initial dye concentration were evaluated to obtain optimum conditions. Results disclosed that the maximum removal values were related to the pH of 4, an adsorbent dosage of 0.2 g, contact time of 15 min, and a dye concentration of 20 mg/L. Experimental data were fitted to the Freundlich isotherm and Pseudo-second-order with the coefficient of determination (R2) equal to 0.9991 and 0.9994, respectively. The maximum adsorption capacity (qmax) was 61.72 mg/g from the Langmuir isotherm. All these results prove that prepared CS-nZVI-Ni could be considered as an adsorbent with high efficiency and cost-effectiveness for dye removal and as an alternative to other adsorbents.