Kinetics and thermodynamic studies on the removal of Cd (II) from aqueous solution using fire clay – TiO2 nanocomposite and fire clay

The present study was aimed at investigating the adsorption behaviour of Cd(II) ions onto Fire Clay+TiO2 Nanocomposite (NC) and Fire Clay (FC). The effects of several parameters such as adsorbent dose, contact time, initial concentration, pH & temperature had been studied. The adsorption followed pseudo second order, Elovich and intra particle diffusion models. The adsorption of Cd (II) was found to be maximum in the pH range 6.5-10. The data on the adsorption on both clay and nanocomposite fitted well with Langmuir, Freundlich, D-R isotherms and fairly well with Temkin model. The thermodynamic parameters G0, H0, S0 have also been evaluated. Adsorptions on both adsorbents were found to be exothermic and chemisorptive in nature. The nanocomposite exhibited a better removal efficiency for divalent Cd than the clay.