Removing diazo direct red 81 using chitosan/zero-valent iron nanocomposite from aqueous solutions and process Optimization

ABSTRACT

A simple and rapid approach based on chitosan/zero-valent nanocomposite (CS-nZVI) was synthesised for efficient removal of diazo Direct Red81 from aqueous medium.This nanocompositewasidentified and characterised by Field Scanning Electron Microscope (FSEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy(FTIR). The effect of different parameters such as contact time, adsorbent dosage, pH, initial concentration of dye, and temperature were examined. The highest removal efficiency was about 97% at an adsorbent dosage of 0.2 g L⁻¹, contact time of 12 min, pH = 7, and the pollutant concentration of 10 mg L ^{– 1}. Also, the highest removal value of real sample (Textile effluent) was 85%. Langmuir and Freundlich adsorption isotherms were examined that was better matched to the Freundlich adsorption isotherm model with R² = 0.9082. The Pseudo-first-order and Pseudo-second order kinetics were also investigated which was understood that it follows Pseudo-first-order kinetic with R² = 0.9602. Finally, thermodynamic study in different temperatures, which showed that The reaction is spontaneous and endothermic.

KEYWORDS:

• Nanocomposite
• chitosan
• zero-valent iron
• azo dye
• direct red 81

Disclosure statement

No potential conflict of interest was reported by the author(s).