Alkaline earth metal modulation of MoS2 crystalline phases for desolvation and selective adsorption of hydrated lead ions

In this study, an alkaline earth metal doped molybdenum disulfide composite (AEM@MoS 2 , AEM = Ca, Sr, Ba) was presented, which can convert the desolvation process from non-spontaneous to spontaneous during heavy metal adsorption. The doping of MoS 2 by AEM not only increases the ratio of surface-active phases, but also modulates the energy band structure, so that Pb 2+ in solution was spontaneously exposed from the hydrated clusters and was more easily adsorbed on the AEM@MoS 2 surface. Among them, the maximum adsorption amount of Ba-MoS 2 reached 147.84 mg/g and the selectivity coefficient for Pb 2+ was as high as 254.58. The precipitation experiments yielded a Pb 2+ precipitation rate of 10.94 % under the condition of pure water, and molecular dynamics simulation (MD) yielded the diffusion coefficient of Pb 2+ being adsorbed on the surface of Ba-MoS 2 to be only 2.00 × 10 -4 Å 2 ·ps −1 . It was verified that it has excellent anchoring ability for Pb 2+ and effectively avoids the secondary pollution caused by desorption. This work can provide a new idea for improving the mechanism of the heavy metal hydrated ion adsorption process.