Isotherm, kinetics and thermodynamic parameters study of arsenic (III) and copper (II) adsorption onto Limonia acidissima shell carbon
Virender Yadav, D. P. Tiwari, Mamta Bhagat
Abstract
ABSTRACT The adsorption of heavy metal ions As(III) and Cu(II) from aqueous solution on activated carbon prepared from Limonia acidissima shell was studied in batch mode. Different characterization of Limonia acidissima shell carbon was carried out using Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and Brunauer–Emmett–Teller. The effects of various parameters such as contact time, initial heavy metal concentration, and dosage of Limonia acidissima shell carbon were investigated. The process optimization of mentioned parameters was also intended, and it was observed that around 92.2% of As(III) and 84.1% Cu(II) ions were removed with 50 mg of Limonia acidissima shell carbon at 303 K with 180 min. The adsorption kinetic studies showed that the adsorption follows the pseudo-second-order model for both As(III) and Cu(II). The equilibrium data were analyzed using Langmuir, Freundlich, Temkin, and D-R adsorption isotherm models. The adsorption of As(III) and Cu(II) in single solution followed the Langmuir isotherm model. The maximum adsorption capacities of Limonia acidissima carbon for As(III) and Cu(II) were 68.77 and 76.92 mg/g, respectively. The positive enthalpy change for adsorption of As(III) and Cu(II) on Limonia acidissima shell carbon confirms the endothermic nature of adsorption while Gibbs’s free energy change confirms the spontaneity of the process.