Retention of copper and nickel from aqueous solutions using manganese oxide-coated burned brick

Experiments were conducted to evaluate copper and nickel sorption on artificially manganese oxide-coated burned brick (MCBb), a waste by-product of brick industry. The effect of metal concentration, contact time, solution pH, and temperature on the amount of Ni(II) and Cu(II) sorbed was studied and discussed. Langmuir and Freundlich isotherm constants and correlation coefficients for the present systems at different temperatures were calculated and compared. The equilibrium process was well described by the Langmuir isotherm model: the maximum sorption capacities (at 293 K) were 2.4 mg Ni/g and 3.7 mg Cu/g for MCBb. Isotherms were also used to evaluate the thermodynamic parameters (?G degrees, ?H degrees, and ?S degrees) of adsorption. The sorption kinetics was tested for the pseudo-first order, pseudo-second order, and intraparticle diffusion models. Good correlation coefficients were obtained for the pseudo-second-order kinetic model, showing that nickel and copper uptake process followed the pseudo-second-order rate expression. (c) 2011 American Institute of Chemical Engineers Environ Prog, 2011