Process development for the removal of hazardous anionic azo dye Congo red from wastewater by using hen feather as potential adsorbent

Removal of an anionic azo dye Congo red has been carried out from its aqueous solutions by using hen feathers as potential adsorbent. In the present paper, detailed chemical and physical analysis of hen feathers and its characterization through scanning electron microscope (SEM), X-ray diffractophotometer (XRD), and (infra red) IR measurements has been explained. The adsorption of an azo dye Congo red has been investigated onto the adsorbent hen feather employing batch technique at 30, 40, and 50(o)C temperature. Various essential factors like, adsorbent dosage, dye concentration, pH, and contact time affecting the extent of adsorption have been analyzed. On the basis of Langmuir adsorption isotherms, feasibility of the ongoing adsorption has been ascertained and thermodynamic parameters have been calculated. Attempts have also been made to verify Freundlich, Tempkin, and Dubinin-Radushkevich (D-R) adsorption isotherm models. The experimental data have been applied to the various isotherms and their constant parameters have been determined. The mean adsorption energy obtained through the D-R isotherm gave an understanding about the nature of the adsorption occurring in the removal process. Determination of various thermodynamic parameters such as free energy, entropy, etc. has been accomplished with the help of isothermal data. It has been established that spontaneous adsorption process is operative in the present case. The kinetic measurements indicate dominance of pseudo-second-order process during the adsorption. The investigation supports that the adsorbent hen feather is effective and efficient in removing the toxic dye from wastewaters.