Abstract

Bone charcoal (BC) prepared from cow bone is used as an adsorbent for the removal of hexavalent chromium from water in this study. The effects of Cr (VI) concentration, pH, contact time and the adsorbent dosage were investigated. The equilibrium data were fitted to Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, Koble-Corigon and Redlich-Peterson isotherm models. Apart from R-2, four error functions were used to validate the isotherm and kinetics data. The experimental adsorption isotherm complied with Freundlich and Koble-Corigon equation models (R-2 > 0.99) and the amount of adsorption (q(e)) was 2.2 mg/g. The elevation of BC dose led to a decrease in q(e) and increasing the pH led to the decreasing of Cr (VI) adsorption. The kinetic studies revealed that the adsorption of Cr (VI) complied with the pseudo-first-order kinetic (R-2 > 0.95). Analysis of data with Dubinin-Radushkevich isotherm showed that the energy of Cr (VI) adsorption process onto BC was 4.36 kj/mol, which implies that the adsorption of Cr (VI) onto BC is physical in nature.