Tilapia fish scale, which facilitates both surface adsorption by hydroxyapatite and electrostatic interaction by collagen after boiling in alkaline environment, was used to prepare an adsorbent for the removal of the hazardous azo dye, Ponceau 4R. The prepared adsorbent was characterized by SEM, FT-IR and physical adsorption studies. Adsorption of Ponceau 4R by the prepared adsorbent was achieved under different initial Ponceau 4R concentrations, fish scale adsorbent doses, temperatures and pH conditions. The Freundlich isotherm model represented the experimental data very well. Kinetic studies indicated that the adsorption process followed the pseudo-second-order model and the theoretical maximum adsorption capacity of the fish scale adsorbent was 134.40 mg g−1. The adsorption thermodynamics study indicated that the adsorption process was a spontaneous and exothermic process.
