Application of graphene-like layered molybdenum disulfide and its excellent adsorption behavior for doxycycline antibiotic

Graphene-like layered molybdenum disulfide (g-MoS2) was prepared by hydrothermal synthesis method, which was characterized by atomic force microscopy (AFM), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS). The performance of using g-MoS2 as an adsorbent for removal of doxycycline (DC) antibiotic from aqueous solution was investigated. The adsorption kinetics, isotherms, thermodynamics and effects of solution pH, ions strength on the adsorption were evaluated in batch adsorption experiments. Compared with the purchased commercial MoS2, g-MoS2 showed higher adsorption capacity around 310 mg g(-1) in the range of pH 4-9. Although both pseudo-first and second order equation described the adsorption kinetics rationally, pseudo-second-order model showed better fit with high R-2. Langmuir model provided the best fit to the equilibrium data and the Langmuir maximum adsorption capacity was found to be 556 mg g(-1) at pH 6. The adsorption was a spontaneous and endothermic process deduced by the thermodynamic analysis. With Na+ in the solution could promote the adsorption. The adsorption mechanism was probably pi-pi interaction, hydrophobic effect and electrostatic interaction. All these results indicated that the prepared g-MoS2 was a potential adsorbent for the removal of DC antibiotic from aqueous solution. (C) 2013 Elsevier B.V. All rights reserved.