Adsorption characteristics of Ni(II) on γ-type alumina particles and its determination of overall adsorption rate by a differential bed reactor

The adsorption experiment of nickel ion [Ni(II)] on γ-type alumina by a differential bed reactor in aqueous solutions was investigated to determine the adsorption characteristics and overall adsorption rate. The adsorbed amount increased rapidly with pH from pH 2 to 6 and kept constant over pH 6. The adsorbed amount of Ni(II) increased with temperature from 20 to 50 °C. Correlation coefficients (R2) of Langmuir and Freundlich adsorption isotherms were 0.9268 and 0.9489, respectively, and Freundlich isotherm was more suitable for adsorption on γ-type alumina than Langmuir isotherm. The overall adsorption rate of Ni(II) on γ-type alumina at pH 6 by a differential bed rector was determined as follows:r=68.77Ce1.61−17.60qe0.36 Al(III) ions in solutions were away from the alumina surface during the adsorption of Ni(II) and Al(III) concentration increased with an increasing Ni(II) adsorbed amount on alumina.