Experimental study on adsorption of Hg(II) with microwave-assisted alkali-modified fly ash

Microwave alkali-modified fly ash was prepared as an adsorbent for mercury (II) in aqueous solution and its adsorption kinetics and mechanism are reported in this paper. The adsorption isotherm could be predicted by the Langmuir isotherm model and the saturated adsorption capacity was 2.6663 mg.g(-1), which indicated that it was monolayer adsorption. It was also found that the quasi-second-order kinetic model could describe the entire process of adsorption, while the quasi-first-order kinetic equation could only reflect the initial stage of adsorption. The adsorption rate was also affected by intra-particle diffusion and by liquid film diffusion or other membrane diffusion. (C) 2019 Elsevier B.V. All rights reserved.