Removal of dye contamination from real textile wastewater by zero-valent iron nanoparticles@chitosan (nZVI@CS) nanocomposite

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In this study, the nZVI@CS nano-absorbent was synthesized with a chemical reduction method and then characterized by FTIR, XRD, FESEM, EDS mapping, and BET analyses. The nZVI@CS had a uniform morphology and suitable functional groups for dye removal. After characterization, the nZVI@CS nano-absorbent was used to remove the dye from real and synthetic wastewater. For this goal, the operation condition was optimized by array L16 of the Taguchi design experiment. The results indicated that the dosage of nano-absorbent with 52% impact had the most effect on the dye removal efficiency. At the optimum condition (pH = 6, T = 25 °C, nanocomposite dosage = 0.01 g, and t = 60 min), the nZVI@CS nano-absorbent could be removed 99%, 96% and 88% of reactive red 81, real wastewater and reactive blue 41, respectively. Additionally, isotherms, the kinetic and thermodynamic of the adsorption reaction were assessed. The kinetic reaction has been similar to the pseudo-first-order model. Also, the isotherm followed the Langmuir isotherm. Moreover, thermodynamic investigation outcomes indicated absorption reactions were exothermic. The reuse ability experiment indicated that the synthesized nZVI@CS nano-absorbent could be used several times without remarkable loss of the sorption ability. Finally, it confirmed that the nZVI@CS nanocomposite has sufficient sorption capacity for dye wastewater on a large scale.