Synthesis of molybdenum disulfide/reduced graphene oxide composites for effective removal of Pb(Ⅱ) from aqueous solutions

【摘要】：In this work,a facile method was adopted to synthesize molybdenum disulfide/reduced graphene oxide(MoS_2/rGO) composites through an L-cysteine-assisted hydrothermal technique.The as-prepared MoS_2/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 MoS_2/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 MoS_2/rGO composites exhibited excellent adsorption capacity of384.16 mg g ~1 at pH 5.0 and T= 298.15 K,which was superior to MoS_2(279.93 mg g ~1) and many other adsorbents.The thermodynamic parameters suggested that the adsorption process of Pb(Ⅱ) on MoS_2/rGO composites was spontaneous(AG~θ 0) and endothermic(AH~θ 0).The interaction of Pb(Ⅱ) and MoS_2/rGO was mainly dominated by electrostatic attraction and surface complexation between Pb(Ⅱ) and oxygen-containing functional groups of MoS_2/rGO.This work highlighted the application of MoS_2/rGO as novel and promising materials in the efficient elimination of Pb(Ⅱ) from contaminated water and industrial effluents in environmental pollution management.