Sequestration of Copper (II) and Iron (II) Ions from Electroplating Effluent Using Crab Shells Chitosan Stabilized Silver Nanocomposite

Abstract

This work presents the green preparation of chitosan stabilized silver nanocomposite using aqueous leaf extracts of Nicotiana tobaccum. The prepared chitosan – silver nanocomposite was characterized by the ultraviolet-visible (UV-Vis) spectroscopy, X-ray diffraction (XRD), high resolution scanning electron microscopy (HRSEM) and Fourier transform infrared (FTIR) spectroscopy. The nanocomposite was employed to remove copper and iron metal ions from electroplating effluent via batch adsorptions as a function of contact time, adsorbent dosage and temperature. The XRD results of the nanocomposite showed reflections at 2θ of 38.04°, 44.650 and 64.45° for the presence of silver nanoparticles and 9.29° and 19.300 for chitosan. The HRSEM image of the nanocomposite shows the silver nanoparticles embedded in the chitosan polymer matrix, to create pores on the surface of the chitosan. The maximum percentage removal of copper and iron by chitosan – silver nanocomposite were 94.76 % and 98.80 % respectively at temperature of 363 K in 60 minutes using adsorbent dosage of 25 mg. The results were well fitted by all the tested isotherm models but best fit into jovanovic isotherm models. Kinetic data for Cu and Fe ions followed the Elovich model which implies multilayer adsorption. The result of this study show that chitosan - silver nanocomposite has been prepared and it exhibit high adsorption efficiency for copper and iron from electroplating effluent.

Keywords

• heavy metals
• electroplating effluent
• adsorption
• crab shell
• nanocomposite