The performance and kinetics of flower-like MoS2 for Hg2+ removal from acidic wastewater

Abstract

In this study, flower-like MoS2 was synthesized under non-equilibrium conditions for effectively absorbing Hg2+ from acidic wastewater. The prepared flower-like MoS2 was characterized using XRD, FESEM, BET, and EDS analyses. The effects of initial concentration of Hg2+, pH, temperature, and common anions on the adsorption performance of flower-like MoS2 were investigated. The results showed that the removal of Hg2+ from a solution with the initial concentration of 200 mg/L Hg2+ was close to 100 % within 60 min. The maximum adsorption capacity was 1790 mg/g at 25 °C. The regression coefficient for the adsorption of Hg2+ conformed to the pseudo second-order kinetics, and the adsorption isotherm was more consistent with Langmuir model, indicating that the removal of Hg2+ using flower-like MoS2 was through monolayer adsorption. The reaction activation energy for the adsorption of Hg2+ by flower-like MoS2 was 26.89 kJ/mol, which again verified that the synthesized material was a fast and efficient adsorption material. Based upon the results, it is inferred that the flower-like MoS2 has a high ability for removing Hg2+ from wastewater and therefore, exhibits broad application prospects.