Removal of Cr(VI) from aqueous solution using brick kiln chimney waste as adsorbent

AbstractHeavy metals are toxic to aquatic flora and fauna even in relatively low concentrations. Chromium is a commonly occurring toxic metal in ecosystems. This study aims the adsorption of Cr(VI) on a novel low-cost carbonaceous material under different experimental conditions such as contact time, initial concentration of metal ions, pH, and temperature. The adsorbent was characterized by using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The equilibrium data were fitted well with Langmuir and Freundlich isotherms. Adsorption kinetics of Cr(VI) ions onto chimney waste adsorbent were analyzed by pseudo-first-order and pseudo-second-order models. The adsorption process is favored by acidic pH and followed the second-order kinetics. Various thermodynamic parameters like activation energy (Ea), Gibbs free energy change (ΔGo), enthalpy change (ΔHo), and entropy change (ΔSo) were calculated. The results showed that the carbonaceous material obtains from bricks kiln chimneys can be efficiently used for Cr(VI) removal from wastewater.