Application of Mg-mesoporous alumina prepared by using magnesium stearate as a template for the removal of Nickel: Kinetics, isotherm, and error analysis

A new and novel adsorbent of Mg-mesoporous alumina prepared via a templating method was used to adsorb nickel from aqueous solution. The adsorption mechanism is assumed to be an ion exchange between Ni(II) and magnesium ion present on the surface of the newly prepared mesoporous alumina. The sorption was examined in terms of its equilibria and its kinetics. The sorption data have been analyzed and fitted to the linearized adsorption isotherms of the Freundlich, Langmuir, Temkin, and Dubin-Redushkevich models, The kinetic studies showed that the sorption rates could be described well by a pseudo-second-order expression rather than by the more commonly applied Lagergren pseudo-first-order kinetic model. The best fitting of experimental results to the proposed isotherms was observed in models that assume that ionic species bind first at the energetically most favorable sites. The results show that Mg-mesoporous alumina holds great potential to remove Ni(II) species from aqueous solution because the AG value of Mg(II), which is present in mesoporous alumina, has a more negative value when compared with Ni ion.