Construction of MoS2 nanoarrays and MoO3 nanobelts: Two efficient adsorbents for removal of Pb(II), Au(III) and Methylene Blue.

Toxic heavy metal ions, valuable noble metal ions and organic dyes are significant concerns in wastewater treatment. In this work, MoO3 nanobelts (MoO3 NBs) prepared by solvothermal method and MoS2 nanoarrays (MoS2 NAs) constructed using MoO3 NBs precursor were proposed to effectively remove heavy/noble metal ions and organic dyes, such as Pb(II), Au(III) and Methylene Blue (MB). The two adsorbents exhibited the excellent adsorption capacity towards Pb(II), Au(III) and MB. The maximum removal capacity of Pb(II) and MB on MoO3 NBs was 684.93 mg/g and 1408 mg/g, respectively, whereas that of Au(III) and MB on MoS2 NAs was 1280.2 mg/g and 768 mg/g, respectively. Furthermore, the thermodynamic parameters were calculated from the temperature-dependent curves, suggesting that the removal of Pb(II) and Au(III) on both adsorbents was spontaneous and endothermic. The new adsorbents introduced here were high adsorption activity, ease of fabrication, high scalability, good chemical stability, great repeatability and abundant and cheap supply, which were highly attractive for wastewater treatment.