Alkaline earth metal modulation of MoS2 crystalline phases for desolvation and selective adsorption of hydrated lead ions
Abstract
In this study, an alkaline earth metal doped molybdenum disulfide composite (AEM@MoS2, AEM?=?Ca, Sr, Ba) was presented, which can convert the desolvation process from non-spontaneous to spontaneous during heavy metal adsorption. The doping of MoS2 by AEM not only increases the ratio of surface-active phases, but also modulates the energy band structure, so that Pb2+ in solution was spontaneously exposed from the hydrated clusters and was more easily adsorbed on the AEM@MoS2 surface. Among them, the maximum adsorption amount of Ba-MoS2 reached 147.84?mg/g and the selectivity coefficient for Pb2+ was as high as 254.58. The precipitation experiments yielded a Pb2+ precipitation rate of 10.94?% under the condition of pure water, and molecular dynamics simulation (MD) yielded the diffusion coefficient of Pb2+ being adsorbed on the surface of Ba-MoS2 to be only 2.00?×?10-4 ?2·ps?1. It was verified that it has excellent anchoring ability for Pb2+ 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.