Abstract
In this work, a facile method was adopted to synthesize molybdenum disulfide/reduced graphene oxide (MoS2/rGO) composites through an L-cysteine-assisted hydrothermal technique. The as-prepared MoS2/rGO composites were firstly applied as adsorbents for efficient elimination of Pb(II) ions. Batch adsorption experiments showed that the adsorption of Pb(II) on MoS2/rGO followed pseudo-second-order kinetic model well. The adsorption of Pb(II) was intensely pH-dependent, ionic strength-dependent at pH < 9.0 and ionic strength-independent at pH > 9.0. The presence of humic acid (HA) enhanced Pb(II) adsorption obviously. The MoS2/rGO composites exhibited excellent adsorption capacity of 384.16 mg g(-1) at pH 5.0 and T = 298.15 K, which was superior to MoS2 (279.93 mg g(-1)) and many other adsorbents. The thermodynamic parameters suggested that the adsorption process of Pb(II) on MoS2/rGO composites was spontaneous (Delta G(theta) < 0) and endothermic (Delta H-theta > 0). The interaction of Pb(II) and MoS2/rGO was mainly dominated by electrostatic attraction and surface complexation between Pb(II) and oxygen-containing functional groups of MoS2/rGO. This work highlighted the application of MoS2/rGO as novel and promising materials in the efficient elimination of Pb(II) from contaminated water and industrial effluents in environmental pollution management. (C) 2017 Science China Press. Published by Elsevier B.V. and Science China Press. All rights reserved.