Mechanism of Cu²⁺and reactive yellow 145 dye adsorption onto eggshell waste as low-cost adsorbent

Abstract

This work presents low-cost sorbent powder obtained from agro-waste of poultry eggshells for the adsorption of contaminants and was elucidated with transmission electron microscopy, Fourier transform infrared, scanning electron microscope, X-ray diffraction and N2 adsorption–desorption techniques. It was observed that a solution pH of 2.0 and 5.0 was enough for the maximum uptake of reactive yellow 145 dye (RY 145) and Cu(II) ions, respectively, which showed that the pollutants removal was affected by the pH of solution. Langmuir monolayer adsorption capacity was found to be 101.500 mg/g for Cu(II) and 88.450 mg/g for reactive yellow 145 dye, respectively. Redlich–Peterson and Sips models both fitted well with the adsorption data. The Pseudo-second-order equation demonstrated good relationship with the experimental data and thus explained the adsorption mechanism to be chemisorption. Values of different thermodynamic considerations gave the values of ΔH° and ΔS° to be 30452.020, 27194.180 and 100.930, 90.370 kJmol−1 for Cu(II) and RY 145 dye, respectively. Findings from this current study revealed that the prepared sorbent from agro-waste of eggshell can be a useful material for the elimination of Cu(II) and RY 145 dye in aqueous solutions.